Versatile Synthesis of Mesoporous Nanomaterials via Monomicelle‐Directed Assembly

ABSTRACT

Mesoporous nanomaterials have attracted significant attention due to their diverse compositions and multileveled architectures. The soft‐templating strategy serves as a foundational methodology for synthesizing mesoporous materials, achieving structural modulation via manipulation of thermodynamic and kinetic pathways during the self‐assembly. In particular, recent breakthroughs in monomicelle‐directed assembly have enabled the precise engineering of the morphologies, nanostructures, and porous architectures. This approach relies on the formation of composite monomicelles composed of block copolymers/surfactants and precursor species, which act as structure‐directed units. The assembly of composites monomicelles through a well‐defined and controlled stacking process resulted in mesoporous nanomaterials. Crucially, the size, composition, and geometry of monomicelles can be readily tailored by optimizing the synthetic conditions, which enables precise control over the architectures inaccessible by conventional approaches. Here, we review the historical development and design principles of monomicelles, along with the synthetic chemistry involved in the assembly of monomicelles with precursors. Subsequently, monomicelle assembly via aggregate and interfacial assembly is highlighted to achieve the controllable synthesis of mesoporous nanomaterials for applications in catalysis (e.g., thermal, electro‐, photo‐catalysis) and energy storage (e.g., batteries and supercapacitors). Finally, current challenges and future opportunities are discussed to enhance the design of mesoporous materials for future applications.

This article outlines the monomicelle‐directed assembly (MMDA) strategy for synthesizing mesoporous materials, emphasizing the interplay between mesoporous structure, properties, applications, and AI guidance, offering new insights and approaches for advancing functional material design.

1. Introduction

Mesoporous materials, valued for their large pore sizes, high surface areas, tunable pore volumes, and chemical versatilities, are widely used in catalysis, energy storage, biomedicine, adsorption, and separation [1, 2, 3, 4]. Their tailored porosity and surface chemistry enhance both reactivity and selectivity, particularly in processes involving large molecular species [5, 6, 7, 8]. Mesoporous materials consist of silica, polymers, carbon, and metal complexes (such as metal oxides, sulfides, and metal‐organic frameworks), offering compositional flexibility to meet the demands of specific applications [9, 10, 11, 12]. Moreover, the structural diversity of these materials, which encompasses tunable morphologies, particle sizes, and pore geometries, gives rise to emergent properties such as size‐selective molecular sieving, directional mass transfer, and stimuli‐responsive cargo release, offering a platform to explore structure‐performance relationships [13, 14, 15]. In general, ordered mesopores are typically engineered through templating strategies, categorized as either hard or soft templating approaches [16]. The hard templating method employs preformed sacrificial templates (mesoporous solids or colloidal nanocrystals), enabling the preparation of mesoporous materials with diverse compositions, but its high cost, low tunability, and poor scalability limit practical adoption [1]. In contrast, the soft templating strategy uses amphiphilic surfactants or block copolymers as structure‐directing agents, achieving convenient, scalable, and cost‐effective synthesis with better tunable pore architectures.

Among soft‐templating strategies, liquid crystal templating (LCT) [17] and cooperative self‐assembly (CSA) [18] stand out as the most widely recognized mechanisms, playing a central role in advancing mesoporous materials research [19]. Despite these advances, most reported mesoporous materials are synthesized in bulk form (typically larger than several micrometers) through the aforementioned mechanisms, which significantly hinder mass transfer and limit access to active sites. In addition, the field still lacks a unified understanding of mesoporous material formation, and progress toward controllable, on‐demand synthesis requires both a universal synthesis method and a robust theoretical framework [20]. Consequently, researchers have sought more refined approaches to controlling micelles assembly to synthesize tailored mesoporous materials with nanoscale size [21]. Recent advances in monomicelle‐directed assembly (MMDA) mechanisms have established new pathways for precision synthesis of mesoporous nanomaterials [22]. Here, we specifically use the term “monomicelle” to denote strategies that begin with discrete, stabilized composite micelles as building blocks, in contrast to the broader concept of soft‐templating assembly, which typically refers to LCT or CSA based on micelle ensembles. In particular, the MMDA process can be modularly and stepwise described in four interdependent stages (Figure 1a): (I) self‐assembly of templating agents into monomicelles (Figure 1b,c), (II) framework precursors assembly around monomicelles (Figure 1d), (III) crosslinking/polymerization into mesostructured composites (Figure 1e), and (IV) template removal to yield mesoporous architectures (Figure 1f). The inherent modularity of these steps facilitates flexible design and systematic optimization of mesoporous materials with tailored structures, compositions, and functionalities through the control of micelle geometry, precursor reactivity, interfacial interactions, etc.

FIGURE 1.

(a) A typical synthetic process for fabricating mesoporous nanomaterials through MMDA strategy. (b) Categories and structures of common amphiphilic block copolymers and surfactants. (c) Three common morphologies of micelles. (d) Two strategies for the assembly of monomicelles and precursors. (e) Diverse morphologies of mesostructured composites. (f) Categories of functional mesoporous nanomaterials.

Previous reviews have provided valuable summaries of progress in monomicelle‐directed assembly of mesoporous materials; here, we extend these efforts by offering a more integrated and updated framework enriched with additional insights and interpretations [20]. This review highlights the key steps in the MMDA strategy, emphasizing recent breakthroughs in synthetic control and mechanism insights. We summarize the design and preparation of monomicelle building blocks, the control of interactions between templates and precursors, as well as the modulation of monomicelle assembly to achieve the precise synthesis of functional mesoporous nanomaterials (Figure 2). Further, we emphasize structure‐property relationships influenced by mesopore effects, including mass‐transfer diffusion, interface effects, confinement effects, pore‐selective and spatial limiting effects across multiple scales (from sub‐nanometre to nanometre and even to sub‐micrometre scales). These engineered mesopore effects are critical determinants of performance in catalysis (e.g., thermal, electro‐, photo‐catalysis) and energy storage (e.g., batteries, supercapacitors). We discuss the development and design principles of mesoporous nanomaterials, offering suggestions for their advancement in emerging applications. Through these developments, we aim to provide a comprehensive understanding of the mechanisms underlying nanostructured mesoporous materials synthesis and their potential applications across various fields.

FIGURE 2.

Schematic illustration of structural manipulation, properties, applications, and AI guidance, with a focus on the synthesis of mesoporous materials.

2. Construction of Monomicelle Building Blocks

2.1. Strategies for the Formation of Monomicelles

In soft‐templating approaches, monomicelles serve as the sub‐units for constructing mesoporous architectures. The spatial ordering and hierarchical assembly of these monomicelles drive the evolution of mesostructures. In general, micelles are formed by the assembly of surfactants or amphiphilic block copolymers in polar solvents with hydrophobic moieties oriented inward and hydrophilic segments facing outward, thus forming core@shell architectures [23, 24]. Conversely, this spatial arrangement is inverted in nonpolar media. Upon micellization, individual micelles interact with precursors or oligomers to generate composite monomicelles. Crosslinking and polymerization of oligomers promote further assembly of the micelle units, resulting in mesostructured composites. However, suppressing micelle aggregation during precursor polymerization preserves monomicelle isolation, thereby enabling the synthesis of discrete composite monomicelle architectures [25]. However, due to the dynamic nature of micelles, they tend to aggregate and form liquid crystalline phases to minimize Gibbs free energy, which often hinders the preparation of monomicelles. Therefore, preventing the aggregation of composite monomicelles is key to achieving monodispersed ones.

During the preparation of monomicelle nanostructures, it is necessary to maintain the concentration of surfactants or block copolymers at relatively low concentrations. This helps reduce the number of micelles, thereby slowing down their aggregation. However, it is important to note that, during this process, the concentration of surfactants or block copolymers must remain above the critical micelle concentration (CMC) to ensure the formation of micelles. Additionally, due to the rapid hydrolysis and crosslinking reactions of the precursor, a terminator must be introduced early, before the composite monomicelle aggregation process, to halt the reaction, thereby ensuring the formation of stable monomicelle structures. In a representative synthesis, Huo et al. employed F127 triblock copolymers as structural templates, using tetraethoxysilane (TEOS) as the silica precursor and diethoxy(dimethyl)silane (DEDMS) as the crosslinking inhibitor to achieve monomicelle‐templated hollow silica nanospheres [26], as shown in Figure 3a. The addition of DEDMS inhibited further crosslinking polymerization of silica oligomers, thereby preventing aggregation and maintaining the morphology of monomicelles. Mechanism studies revealed that the inhibitory effect of organosilane terminators correlates with their hydrophobic chain length (R) [27]. In RSi(OEt)₃ derivatives, elongating the hydrophobic R‐groups in organosilane inhibitors sterically hinders Si‐OH crosslinking through increased van der Waals repulsion, thereby stabilizing monodispersed silica nanoparticles templated from monomicelles.

FIGURE 3.

Schematic illustration of the formation of monomicelles and the transmission electron microscopy (TEM) images of monomicelle‐based nanostructures templated by various surfactants or block copolymers: (a) ABA‐type copolymers [26] (Copyright 2006 American Chemical Society), (b) cationic surfactants under the mediation of TMB [28] (Copyright 2018 American Chemical Society), and (c) ABC‐type block copolymers [24] (Copyright 2021 Wiley‐VCH GmbH).

In addition to non‐ionic surfactants, ionic surfactants can also be used to prepare silica monomicelle nanostructures. Ma et al. have employed the cationic surfactant cetyltrimethylammonium bromide (CTAB) as the template, trimethylbenzene (TMB) as a mediator inside the core of monomicelle, tetramethyl orthosilicate (TMOS) as the silica source, polyethylene glycol (PEG) as the capping agent to terminate nanoparticle growth [28, 29]. This approach can yield monodispersed mesoporous silica nanoparticles with an ultrasmall size (<10 nm) and exceptional stability, as shown in Figure 3b. Furthermore, the number of mesopores per nanoparticle can be precisely tuned from 1 to more than 4, demonstrating the programmable construction of porous architectures [30]. Cryo‐electron microscopy images, combined with single‐particle three‐dimensional reconstruction technology, confirm that these silica nanoparticles are independent silica cages with an icosahedral structure [31]. Unlike nonionic F127 micelles, micelles assembled from CTAB exhibit cationic surfaces due to the quaternary ammonium headgroups. In this context, electrostatic interactions between cationic micelles and anionic silica oligomers drive inhomogeneous oligomer deposition, templating the icosahedral nanocage topology. This finding opens new avenues for the construction of nanoscale inorganic cage‐like materials. Further studies on the growth process of silica nanocages reveal that silica clusters, approximately 2 nm in size, initially arrange around the micelle, forming ultra‐small silica rings, which then evolve into the cage‐like structure [28]. Interestingly, as the PEG concentration increases, these rings align to form segmented and worm‐like one‐dimensional structures. These one‐dimensional structures can further arrange themselves into two‐dimensional sheets or three‐dimensional helical higher‐order assemblies. This study provides valuable insights into the early‐stage morphological transformations of oligomers during the formation of mesoporous nanomaterials.

In addition, Zhao et al. have developed ABC‐type triblock copolymers polystyrene‐b‐poly (2‐vinylpyridine)‐b‐poly(ethylene oxide) (PS‐b‐P2VP‐b‐PEO) and poly(ethylene oxide)‐b‐poly(acrylic acid)‐b‐polystyrene (PEO‐b‐PAA‐b‐PS) for the construction of monomicells [24]. Based on their molecular architecture design, these copolymers can assemble into stable monomicelles with a core‐shell‐corona structure as illustrated in Figure 3c. In this case, oligomers are selectively assembled into the middle layer of the monomicelles via electrostatic attraction, hydrogen bonding and/or coordination interactions. Once the middle layer of the monomicelle is occupied by the oligomers, the corona layer acts as a barrier to prevent further crosslinking and aggregation, thereby inhibiting the aggregation of monomicelles. Based on this strategy, a series of hollow nanoparticles with various compositions have been successfully synthesized, including silica, polydopamine, organosilicon, metals, and metal oxides (ZnO, TiO₂, Fe₂O₃, CaCO₃, WO₃, V₂O₅, Nb₂O_5, and NiO, etc.) [32]. Remarkably, during the nucleation and growth of the oligomers, the corona layer derived from the ABC‐triblock copolymers remains fully exposed. This structural feature introduces abundant surface functional groups to the nanostructures, enabling facile surface modification, thereby promising for applications in drug delivery, catalysis, energy conversion, and storage.

2.2. Structure Engineering of Monomicelles

Using surfactants or block copolymers as templates, the final assembly morphologies of monomicelles are primarily governed by the packing parameter (p = v/a₀l_c ), where v, l_c and a₀ denote the hydrophobic segment volume, length, and hydrophilic block contact area, respectively (Figure 4a) [33]. It plays a crucial role in determining the self‐assembly behavior of the micelles. For p < 1/3, spherical micelles form preferentially, ultimately yielding hollow nanospheres [24]. At intermediate values (1/3< p < 1/2), cylindrical micelles dominate, resulting in materials with tubular architectures [34]. At higher packing parameters (1/2< p < 1), vesicles or modulated lamellar structures emerge, which typically lead to the formation of nanosheets [35]. Since the mesostructure largely depends on the morphology of micelle units, controlling the assembly of monomicelles enables the synthesis of mesoporous materials with tunable structural diversity [6]. In general, precise control over pore structure (size, distribution, and connectivity) is crucial, as it directly influences the efficiency of mesoporous materials in applications.

FIGURE 4.

Tunable monomicelle architectures. (a) Schematic illustration of micelle morphology transitions governed by the packing parameter (p) [24, 34, 35] (Copyright 2021 Wiley‐VCH GmbH, Copyright 2016 American Association for the Advancement of Science, Copyright 2022 American Chemical Society). (b) Key strategies for tuning the size of micelles, which largely determine the pore size of resultant mesoporous materials [24] (Copyright 2021 Wiley‐VCH GmbH).

Additionally, there are two typical methods for tuning the size of monomicelles, which significantly determine the pore size of mesoporous materials. Adjusting the hydrophobic chain length of surfactants or block copolymers offers a straightforward and reproducible method for tuning pore sizes. Longer hydrophobic chains result in larger micelles, which ultimately lead to the formation of larger pores (Figure 4b) [36]. However, this method is constrained by the limited availability of suitable surfactants and potential compromises in structural order. In contrast, incorporating hydrophobic swelling agents, such as trimethylbenzene (TMB), toluene, cyclohexane, and polystyrene (PS) offers more flexibility in achieving larger pores by expanding monomicelle cores [37]. More importantly, the introduction of swelling agents can alter the phase separation behavior of surfactants or block copolymers and facilitate the formation of monomicelles in a mixed solvent system, such as ethanol‐water mixture [38, 39, 40]. In addition, variation in the content of hydrophobic agent enables precise modulation of monomicelle quantity, size, and morphology, providing an effective way for mesostructure modulation [41, 42].

3. Interaction‐Guided Formation of Functional Composite Monomicelles

Controlling the assembly of functional species around monomicelles is a crucial step in the successful synthesis of mesoporous nanomaterials, as the physicochemical characteristics of the precursors vary significantly. Effective assembly requires molecular‐level engineering of interactions between templating agents (e.g., surfactants, block copolymers) and precursors at their hydrophilic regions, such as hydrogen bonding, electrostatic forces, or coordination interactions. These interactions facilitate the co‐assembly of precursors and templates into composite monomicelles, which represent a very important design principle in the synthesis of mesoporous materials.

There are two primary approaches for controlling the assembly of monomicelles with precursors. The first approach involves enhancing the interaction between the template and precursor by selecting and designing functional groups on the template (Figure 5a). For example, electrostatic attraction is one of the most common intermolecular forces, typically between cations and anions (Figure 5b). CTAB, a widely used cationic surfactant, is frequently employed to synthesize mesoporous materials, such as silica [43], metals [9], metal oxides [44] and metal‐organic frameworks (MOFs) [10]. Non‐ionic template agents typically interact with the precursors through hydrogen bonding, making them suitable for the preparation of mesoporous polymers, such as resin, polydopamine, polypyrrole, and polyaniline (Figure 5c) [45, 46, 47]. Notably, mesoporous polymers can be easily transformed into corresponding mesoporous carbon materials after high‐temperature calcination. Additionally, coordination interactions are also significant, particularly in the formation of mesoporous materials involving metal ions, such as metal oxides and MOFs (Figure 5d). In this context, templates are usually functionalized with strong coordination groups, such as ─COOH, ─NH₂ and ─OH, which are capable of effectively anchoring the metal ions. For example, Li et al. used amphoteric surfactants containing a carboxylate group, which self‐assemble into rod‐shaped micelles. In this case, the ─COOH groups at the shell of the micelles strongly coordinate with the Zr–O clusters, thus guiding the assembly of MOF precursors and directing the crystallization of MOFs into well‐ordered hierarchical structures [48]. While other types of intermolecular interactions, such as covalent bonding and hydrophobic interactions, can also be used in the synthesis of mesoporous materials [49]. However, due to the difficulty of constructing these interactions or their insufficient strength to effectively support the assembly of framework precursors with the templating agent, these interactions are less frequently applied.

FIGURE 5.

(a) Schematic illustration of direct assembly of monomicelles and precursors via (b) electrostatic interaction, (c) hydrogen bonding, and (d) coordination interaction and other methods. (e) Schematic illustration of bridge assembly of monomicelles and precursors via (f) small molecules, (g) polymers, and (h) ions.

The second approach is used when the interaction between the template and precursor is weak for the assembly. In this case, extra functional units can be introduced to bridge the interaction between the monomicelle and precursor, thereby facilitating their assembly (Figure 5e). Organic molecules with multiple functional groups serve as excellent bridging compounds. For example, by combining coordination and assembly chemistry, Wang et al. have achieved controllable interaction between multiple metal ions and F127 micelles mediated by citric acid [50]. This method successfully synthesized mesoporous polymetallic oxides with precise stoichiometric ratios, such as lithium‐titanium oxides (Li₄Ti₅O₁₂, LiTiO₂, etc.), by adjusting the feed ratio of the citric acid chelates of titanium and lithium (Figure 5f) [51, 52]. Based on similar principles, Zheng et al. have developed a phenolic resin‐assisted cationic coordination co‐assembly strategy to prepare oxygen‐deficient mesoporous ABO₃‐type perovskite oxides (Figure 5g) [53]. During the synthesis, phenolic resin was used to build the structural units and assembled them through hydrogen bonding with F127. At the same time, citric acid can uniformly coordinate with La³⁺ and M²⁺ (where M = Mn, Co, Ni, Fe) ions at the atomic scale, controlling the hydrolysis of metal precursors and the assembly of an ordered mesostructure. Recently, a similar method has also been applied to the synthesis of metal sulfides. Yin et al. have reported the use of CTAB as a surfactant template, sodium citrate as a ligand, PtCl₄ ^{2 −} and pre‐formed Sn₂S₆ ^{4 −} as metal and sulfur sources to successfully synthesize a highly ordered mesoporous Pt₂Sn₂S₆ network [54]. Other chelating ligands, such as ascorbic acid (AA), can also be used as ligands to bridge the cooperative assembly of templates and precursors. Liu et al. have developed a method that uses cetyltrimethylammonium chloride (CTAC) as a surfactant (S), metal ions (M^x+) as precursors, and AA as a bridge ligand (L), achieving the universal coating of mesoporous metal hydroxides and oxides on silica spheres via the interaction mode (S⁺ L⁻ M^x+) between organic and inorganic components [55]. The introduction of a bridge ligand is also helpful for developing novel mesoporous materials, such as those derived from the assembly of nanoclusters [56], nanocrystals [57], or quantum dots, so more attention should be paid to.

In addition, ions can also be used to modulate the interaction between the monomicelle and precursor (Figure 5h). Zhang et al. have proposed a facile strategy for polyoxometalates (POMs) assisted assembly to synthesize a series of mesoporous carbon materials [58]. In an acidic solution, both p‐phenylenediamine and F127 are protonated, resulting in positive charges. Therefore, negatively charged POMs can act as bridge units to effectively connect both of them, forming stable composite monomicelles through electrostatic interactions. After polymerization, the template was removed through carbonization, resulting in mesoporous carbon spheres uniformly loaded with Mo₂N nanoclusters. Furthermore, in the synthesis of mesoporous Ce‐based MOFs, the introduction of ClO₄ ⁻ attracts and bridges cerium nodes to 1,4‐dicarboxybenzene (BDC) ligands, promoting the crystallization and growth of MOFs around F127 micelles [59]. Thus, highly crystalline, ordered mesoporous cerium‐based MOFs can be obtained after the removal of the templates.

In conclusion, during the assembly of monomicelles with precursors to form composite micelles, it is crucial to consider interactions at both the molecular and atomic scales. This process involves the synergistic cooperation of multiple interactions, including hydrophobic interactions, coordination bonding, hydrogen bonding, and covalent interactions. Effectively balancing these interactions is pivotal for the successful fabrication of mesostructures. Moreover, by carefully modulation of these interactions, mesoporous materials with well‐defined characteristics, such as tailored porosity, stability, and functionality, can be achieved.

4. Monomicelle‐Directed Assembly Strategies

After the successful assembly of precursors with the monomicelles to form composite monomicelles, they can be further assembled into mesoporous nanomaterials. To effectively control the morphology and mesostructure of mesoporous nanomaterials, researchers have developed various strategies, including aggregation assembly and interfacial‐oriented assembly, to modulate the assembly behavior of composite monomicelles.

4.1. Aggregated Assembly of Monomicelles

The aggregated assembly method provides a highly efficient approach for directly fabricating mesoporous nanomaterials with well‐defined spherical or crystalline‐like architectures, which naturally exhibit minimal surface energy due to their thermodynamically stable configurations. Landmark studies in 2007 first demonstrated the monomicelle‐based aggregated assembly method, achieving the synthesis of single crystal‐like mesoporous carbon [60] (rhombic dodecahedron) and silica [61] (SiO₂, icosahedron) through meticulous layer‐by‐layer monomicelle assembly processes. Building on these pioneering studies, researchers have recognized that monomicelles can serve as versatile building blocks for the fabrication of mesoporous nanomaterials. Subsequently, this approach has been used to synthesize a wide range of mesoporous nanomaterials with diverse compositions, including silicas, polymers, carbons, metals, metal oxides, MOFs, and alloys [1]. Current methodologies of aggregated assembly are primarily differentiated by their driving mechanisms, such as evaporation induced, hydrothermal induced and solution‐based assembly.

Evaporation‐induced aggregated assembly (EIAA) is a widely used method for synthesizing mesoporous materials. It works by dissolving structure‐guiding templates and precursors in volatile solvents. As the solvent gradually evaporates, the surfactants concentrate to a level sufficient to reach their critical micelle concentration, at which point they assemble with precursors to form composite monomicelles. Subsequently, the composite monomicelles aggregate to form the mesostructured composite, followed by template removal to yield mesoporous architectures. Using this method, mesoporous materials with various micro‐ and nanostructures, such as silica hollow spheres, nanotubes, TiO₂ microspheres with radial mesochannels, mesoporous carbons, can be obtained by manipulating the assembly process [62, 63, 64, 65]. By adjusting parameters such as solvent evaporation rate, precursor concentration, the pH and polarity of the solution, researchers can control the morphology, mesostructured, crystallographic orientation, and phase composition of the material. For example, Zhang et al. have demonstrated that the phase composition of mesoporous TiO₂ microspheres can be precisely controlled by manipulating the concentration of HCl [66]. At a low concentration of HCl, the titanium‐oxygen octahedra are connected by shared edge, anatase phase tends to form. Conversely, at a higher concentration of HCl, rutile forms preferentially, characterized by more corner‐shared octahedra. Recently, Lan et al. have introduced a stepwise monomicelle assembly strategy, successfully synthesizing a highly ordered mesoporous TiO₂ film (Figure 6a) [67]. The process involves firstly preparing a monomicelle hydrogel, followed by a secondary assembly step to form the ordered mesoporous film. This step‐by‐step control approach offers a broader reaction window, including parameters such as concentration and assembly time, enabling precise control over the porous structure and thickness of the mesoporous films. Notably, simply adjusting the evaporation rate and HCl additives can control the particle size, mesopore size, crystallinity, and crystalline orientation of TiO₂, thereby achieving the construction of a single‐crystal TiO₂ with uniform mesopores [68]. The ordered mesoporous structure and crystal orientation provide effective mass and charge transport, endowing it with excellent photocatalytic performance.

FIGURE 6.

Schematic illustration and transmission electron microscopy images of aggregated assembly of monomicelles. (a) Evaporation‐induced aggregated assembly [67] (Copyright 2023 The Authors. Published by American Chemical Society). (b) Hydrothermal‐induced aggregated assembly [69] (Copyright 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim). (c) Solution‐based aggregated assembly [41] (Copyright 2019 American Chemical Society).

The hydrothermal strategy is universally applicable for synthesizing nanomaterials and can also be applied to synthesize mesoporous materials by driving the aggregated assembly of composite monomicelles, such as F127@phenolic resol and F127@TiO₂ oligomer composites. In the synthesis of mesoporous polymers and their derived carbon nanospheres, the key challenge lies in preparing composite monomicelles of F127@phenolic resol in an aqueous solution. Subsequently, the phenolic resol oligomer undergoes cross‐linking polymerization to form mesoporous polymer nanospheres during the hydrothermal condition. Notably, by varying the concentration of monomicelles, the size of the resulting mesoporous nanospheres can be finely tuned (Figure 6b) [69]. When applied to composite monomicelles of F127@TiO₂ oligomers, hydrothermal treatment results in the formation of mesoporous TiO₂ microspheres with tunable open crevices [70]. The process involves the selective evaporation of THF in an acidic THF/H₂O solution, forming a gel of F127@TiO₂ oligomer composite monomicelles, followed by hydrothermal treatment. In this process, the composite monomicelles aggregate into larger microspheres to minimize interface tension energy. As the hydrolysis and condensation of TiO₂ oligomers proceed, the vapor pressure inside the microspheres increases, leading to the evaporation of internal solvents and the formation of surface cracks. Moreover, the F127@TiO₂ oligomer composite monomicelles can be readily redispersed in a mixed solution of ethanol and glycerol [71]. This environment created a confined liquid–liquid interface during hydrothermal treatment, directing the assembly of subunits into a two‐dimensional single‐layered mesostructure.

The solution‐based method offers a more convenient and scalable approach, making it suitable for the large‐scale production of ordered mesoporous materials. Due to the abundant self‐assembly behavior of surfactants or block copolymers in solution, the morphology of the formed monomicelles can be controlled by adjusting parameters such as template composition, precursor amount, and solvent system, thereby facilitating the fabrication of mesoporous nanomaterials with well‐defined morphologies, tunable sizes, and pore structures. In solution‐based aggregation assembly, the key process involves the co‐assembly of monomicelles and precursors in appropriate solvent systems to form composite monomicelles, as discussed in the previous chapter. After that, the reaction (polymerization, hydrolysis, condensation, crystallization, etc.) of the precursors or oligomers on the monomicelles drives the aggregation assembly of monomicelles, forming continuous frameworks around the templates and resulting in mesostructured compositions. This route is not only applicable for the fabrication of mesoporous polymers and their derived carbon materials, such as polydopamine, polypyrrole, polyaniline, phenolic resin, melamine resin and urea‐formaldehyde resin, but also for the synthesis of mesoporous metals (Pd, Pt, Rh), multimetallic alloys, metallic compounds (metal borides, metal sulfides, metal oxides) and carbon/metal composites. Notably, solution‐based aggregation assembly techniques have advanced rapidly with the introduction of the nanoemulsion self‐assembly method in recent years (Figure 6c), leading to the synthesis of various mesoporous N‐doped carbon materials and framework materials such as MOFs and COFs [41, 72, 73, 74].

4.2. Interface‐Oriented Assembly of Monomicelles

Although monomicelle aggregation assembly advances mesoporous material engineering, challenges still persist, including morphological irregularities, limited architectural diversity, and difficulties in achieving multifunctional integration. Compared with the one‐phase solution synthetic approach, the introduction of a new interface in the synthetic system changes self‐assembly behaviors of monomicelles, enabling the on‐demand fabrication of unique mesoporous architectures with novel morphologies, compositions, and functions. Recent breakthroughs have demonstrated that the interfacial assembly of monomicelles at gas‐liquid, liquid–liquid, and solid–liquid interfaces brings significant flexibility and diversity in the engineering of mesostructures (Figure 7a–c) [2, 75]. In this regard, based on different interface scales, we classified them into three categories to describe interfacial evolution and their unique characteristics, including macroscale, microscale, nanoscale.

FIGURE 7.

Schematic illustration of interface‐oriented assembly of monomicelles. (a, b, c) Three typical interface for the oriented assembly of monomicelles, including gas–liquid, liquid–liquid and solid‐liquid interface. These interfaces are divided into macroscale (d, e, f), microscale (g, h, i), and nanoscale scales (j, k, l), respectively.

Different interface scales exhibit distinct characteristics in the interfacial assembly of monomicelles, resulting in versatile functional mesoporous nanomaterials [76]. At the macroscale, typically larger than a millimeter, it can be divided into three primary domains: gas‐liquid (e.g., static solution surfaces), liquid–liquid (e.g., immiscible oil‐water biphases), and solid‐liquid interfaces (e.g., bulk substrates such as glass, silicon wafers, or metal foil) [2, 77]. These macroscale systems favor large‐area synthesis, often yielding continuous films, monoliths, and bulk‐structured mesoporous materials. Additionally, the assembly method and interface types are crucial for the final products. For instance, the assembly of composite monomicelles at gas‐liquid interfaces drives the formation of free‐standing mesoporous silica films (Figure 7d), while at the oil‐water interface, it facilitates the formation of silica nanoparticles with dendritic or funnel‐shaped mesopores (Figure 7e) [38, 78]. Solid‐liquid interfaces are commonly used in material synthesis due to their flexibility and controllability. Macroscale solid‐liquid interfaces can be easily constructed by immersing solid substrates (e.g., glass, silicon wafers, PU foam, carbon cloth, metal foil) in a solution, enabling the uniform coating of mesoporous materials such as silicas, polymers, and carbons (Figure 7f) [79, 80, 81]. Despite their utility in mass production, macroscale interfaces typically limit structural precision, making the synthesis of nanosized mesoporous materials difficult.

Transitioning to the microscale, interfacial assembly utilizes confined environments such as microdroplets (gas–liquid), oil microemulsions (liquid–liquid), or templated substrates (solid–liquid) to tailor mesoporous architectures. Microscale gas‐liquid interfaces, achieved via spray‐drying, produce uniform microspheres with hierarchical porosity through rapid solvent evaporation (Figure 7g) [82]. Liquid–liquid systems, such as oil‐in‐water emulsions (Figure 7h), manipulate the assembly of monomicelles at the oil drop interface to guide mesoporous materials into hollow vesicles, multilayered spheres, and asymmetric forms (bowl, egg‐shell, lotus, mushroom, and jellyfish‐shaped) [40, 43, 83, 84]. Solid–liquid interfaces, mediated by microscale templates such as anodic aluminum oxide (AAO) membranes [85], salt substrates [86], and polymers [87], enable the synthesis of unique 2D mesoporous nanosheets (Figure 7i). Other solid templates, such as colloidal crystals and inverse opals, are often applied in the construction of hierarchical macro‐mesoporous materials [88]. These microscale approaches are particularly effective in creating spatially confined structures by balancing interfacial energy and kinetic constraints, however, it makes the synthesis process expensive due to the use of sacrificial templates.

At the nanoscale, interfacial assembly typically exploits nanobubbles, nanoemulsions, or functional nanomaterials as templates to synthesize mesoporous materials with novel physicochemical characteristics. As a result, many research efforts have been focused on this area. The nanoscale gas–liquid interface can be constructed by ultrasonic irradiation, which generates gas bubbles that act as templates, stabilizing monomicelles on their surface to direct the synthesis of hollow silica spheres with ordered mesochannels (Figure 7j) [89]. Moreover, Yamauchi et al. have developed a strategy to construct 2D mesoporous Ir nanosheets using the nanoscale liquid‐gas interface, where CO drives the anisotropic growth of Ir nanoparticles, resulting in ultrathin, polycrystalline mesoporous nanosheets [90]. The nanoscale liquid–liquid interface, formed from either immiscible (e.g., oil–water) or miscible solvent systems (e.g., THF‐water), uniquely directs the self‐assembly of monomicelles. By manipulating solvent interactions, this interface enables oriented assembly of monomicelles, ultimately creating mesoporous materials with tailored architectures. Notably, the recently developed nanoemulsion assembly method has been demonstrated to be universal for the preparation of mesoporous nanomaterials (Figure 7k). As the oil–water ratio increases, the micelles transition to swollen micelles and eventually form bicontinuous structures, leading to different mesoporous architectures [91]. Solid–liquid interfaces can be easily constructed by dispersing pre‐synthesized nanoparticles with specific morphologies in the solution. In this context, monomicelles arrange at the interface of colloidal particles, such as CNTs, GO, MXenes, silica, Fe₃O₄, MOFs, etc., directing the fabrication of core‐shell, Janus, multileveled, and low‐dimensional mesoporous nanomaterials with multiple functions (Figure 7l) [92, 93, 94, 95, 96].

Collectively, interfacial assembly across macro‐, micro‐, and nanoscale interfaces offers a versatile toolkit for designing mesoporous nanomaterials with programmable structures and functions. By harnessing the unique physicochemical properties of each interface, researchers can bridge the gap between bulk synthesis and nanoscale precision, thereby unlocking new frontiers in materials science and nanotechnology.

5. Unique Structural Characteristics of Mesoporous Nanomaterials

The exceptional structure and multifunctionality of mesoporous materials stem from their unique mesochannels. Compared to microporous materials, mesopores provide faster mass transport, and compared to macroporous counterparts, mesoporous materials exhibit higher specific surface areas. Figure 8 illustrates how intrinsic nanochannels in mesoporous structures connect molecular‐scale design to macroscopic functionality, providing key insights for optimizing performance in energy storage, catalysis, and biomedical applications. The key to the functionality of mesoporous materials is the tailored nanochannel geometry, where precise control over pore size (2–50 nm), shape (cylindrical, lamellar, or hierarchical), and connectivity creates directional pathways for selective molecular transport (Figure 8a). As known, an optimal pore structure provides abundant nanoscale transport channels for reactants, enhancing their contact with active sites and thereby accelerating the reaction rate. Moreover, in nanocchannels, pore size often governs key parameters such as the viscosity of the reactant medium, mass transfer rate, contact with active sites, and residence time, all of which collectively influence the reaction activity and selectivity [5, 97, 98]. The uniform pores at mesoscale are crucial for sieving macromolecules or nanoparticles as well. Furthermore, non‐spherical nanochannel geometries, such as radially aligned mesopores in dendritic silica, carbon or TiO₂, mimic the optimized diffusion networks found in nature (e.g., leaf venation). These non‐spherical nanochannels can enhance mass flux and minimize resistance, making them suitable for use in electrodes for fast‐charging batteries and high‐flux filtration membranes [99, 100, 101].

FIGURE 8.

Unique structural characteristics of mesoporous nanomaterials. (a) Providing specific diffusion pathways for facilitating efficient mass transport and selective transport of molecules by adjusting the pore structures (size and shape). (b) Increasing interface sites and easy to interfacial functionalize. (c) Regarding as nanoreactor with nanoconfinement effect. (d) Regulating the curvature of nanoreactor or the spatial location of components to alter internal microenvironments of the nanoreactor and effectively control molecular enrichment and mass transfer. (e) Providing enough space to accommodate guest species.

The interface effects brought by mesochannels can be divided into two aspects: one is that they can enhance the accessibility of active sites, and the other is that they are more easily surface‐functionalized due to the increased exposed interfaces and defects (Figure 8b). Surface‐engineered interfaces within these nanochannels redefine reactivity and molecular recognition. For instance, mesoporous silica films, rich in hydrophilic silanol groups, facilitate rapid ion entry and transport [102]. In contrast, mesoporous carbon films exhibit relatively hydrophobic properties that hinder ion transport [103]. By grafting functional groups (e.g., ─NH₂, ─SH, ─OH, ─COOH, ─SO₃H) or anchoring catalytic clusters (single atoms, nanoparticles), mesoporous surfaces transition from passive substrates to active platforms. Inspired by biological ion channels in the cell membrane, Deng et al. have modified the crown on the mesopore surface. The crown molecule mimics the amino acid group in the K⁺ channel by interacting electrostatically with alkali metal cations, thereby accelerating ion diffusion and promoting the desolvation of hydrated ions [104]. Shi et al. have prepared porous carbon materials grafted with ‐NH₂ functional groups to enhance zinc‐ion storage capacity [105]. The ‐NH₂ groups increase the surface charge density of the carbon, and their lone electron pairs interact strongly with Zn²⁺ ions. This interaction effectively reduces the thickness of the electric double layer, leading to significantly improved ion storage performance. Such interfacial tunability extends to stimuli‐responsive systems, such as pH‐ or light‐sensitive polymers grafted in mesopores [106, 107], enabling on‐demand gating of molecular permeation and achieving breakthroughs in programmable drug delivery and adaptive chemical reactors.

Nanoconfinement effects enhance the inherent advantages of mesopores, transforming them into sub‐nanoscale reaction reactors (Figure 8c). In these spatially confined environments, reactants may undergo changes in solvation structure, limiting rotational freedom and increasing effective concentrations. For example, confined water molecules in mesopores change the strength of the hydrogen bonds and the movement of H₂O, achieving the optimization of catalytic processes [108]. Additionally, in the confinement channels, spatial confinement restricts the inversion of the reactant, causing the dominant product to retain the same configuration as the original reactant [109]. When employed as supports, mesoporous frameworks provide nanoscale confinement that stabilizes metal nanoparticles within their channels, thereby suppressing sintering and growth while enhancing catalytic stability [110]. There is no doubt that nanoconfinement effects in mesopores are crucial in the field of emerging applications, such as catalysis, energy storage, and sensing, which deserve more attentions.

Curvature‐driven molecular enrichment leverages the geometric asymmetry of mesopores to concentrate reactants or guests preferentially (Figure 8d). In general, the concave surfaces of mesopores generate localized electric fields that polarize adsorbed molecules, resulting in molecular enrichment. For instance, mesoporous carbon can concentrate polysulfides and suppress the notorious shuttle effect in lithium‐sulfur batteries [111, 112]. In addition, it has been demonstrated that the curvature radius of mesopores significantly affects ion enrichment. When the curvature radius is drastically reduced (from 145 to 15 nm), the ion concentration increases by a factor of 20, indicating that high‐curvature surfaces can effectively promote ion adsorption [113]. This curvature‐driven enrichment is further enhanced in hierarchically porous structures, where interconnectivity between macropores and mesopores creates gradient concentration fields that guide reactants toward active centers during multistep tandem reactions.

The host‐guest symbiosis within mesopores transcends simple encapsulation, enabling synergistic interactions between the framework and functional species (Figure 8e). For example, halide perovskite nanoparticles are in situ embedded in mesoporous TiO₂ channels, facilitating the formation of a built‐in electric field between the perovskite nanodots, efficiently promoting charge transfer and suppressing the rapid recombination of carriers, thereby achieving efficient and highly selective photocatalytic CO₂ reduction [114]. Moreover, the large space provided by mesoporous channels can effectively accommodate a significant number of guest molecules, enabling efficient molecular storage and enhancing interactions between the guest and host.

6. Applications

6.1. Catalysis

In contrast to microporous zeolites, functional mesoporous materials offer significant advantages in catalytic applications due to their diverse architectures and compositions. Their tunable mesopore sizes effectively eliminate the diffusion limitations that often occur during the reactions involving macromolecules. This is particularly beneficial in catalytic processes involving complex molecules, such as heavy oils or biomass, where traditional microporous materials struggle to accommodate larger molecules.

Beyond their dimensional advantages, ordered mesochannels create nanoconfinement effects that guide reaction pathways by modulating electronic, and geometric features. Additionally, compared to traditional supports, mesoporous materials with high surface area can maximize active site density without sacrificing structural stability, enabling them to function as catalytic nanoreactors. The stability and diversity of the mesostructure enable the precise engineering of active sites at various spatial locations, facilitating the accurate regulation of complex catalytic processes.

The precise alignment of the pore size with the molecular dimensions facilitates efficient substrate diffusion and selective interaction with active sites, thus improving the overall catalytic performance in large molecule‐related reactions. For example, Tennakoon et al. have designed a mesoporous silica catalyst with robust thermal properties to achieve processive hydrogenolysis of polyethylene (Figure 9a) [115]. The mesoporous silica shells (2–3 nm in diameter) show confinement effect to enforce twining plastics polymer resolved through straight chain state, which mimic substrate binding in enzymatic clefts. In addition, the active sites are located on the bottom of the mesopore, which can enable regioselective C–C bond scission with precise chain cracking, resulting in a reliable, narrow, and tunable stream of alkane products. The tailored surface chemistry of mesoporous materials also facilitates the cracking of macromolecules. Feng et al. have presented a tandem porous catalyst architected through micelle cascade assembly, enabling selective polyethylene cracking into olefins at reduced temperatures (Figure 9b) [116]. The catalyst integrates hierarchical porosity at three different scales, with each part having a distinct function. First, macroporous arrays at the periphery leverage capillary forces and hydrophobicity to rapidly adsorb and transport bulky polyolefins. Second, mesopores enforce pre‐cracking the polyolefins driven by nanoconfinement via weak acid sites and fragment polymers into reactive intermediates. Third, microporous of ZSM‐5 cores house strong Brønsted acid sites for terminal C–C scission with spatial precision.

FIGURE 9.

Mesoporous materials in catalysis applications. Thermocatalysis: (a) Processive deconstruction of macromolecules via the confinement of mesopore, (b) Cascade cracking of macromolecules over tandem porous catalyst. Electrocatalysis: (c) Suitable microenvironment regulation via mesoporous carbon carriers, (d) Gas‐diffusion process facilitated by 2D meso‐channels, (e) Spatially separated dual‐metal electrocatalysts achieving tandem reaction. Photocatalysis: (f) Enhancing the surface site and short diffusion distance of electrons and holes, (g) Phase junction structure with rich defects improving the quantum efficiency.

Electrocatalysis plays a central role in clean energy conversion, enabling sustainable processes for future energy technologies. Recently, Jing et al. have presented a catalytic system in which palladium nanoparticles are embedded within hierarchically porous carbon matrices [117]. The resultant catalyst enables high‐efficiency hydrogen peroxide electrosynthesis near thermodynamic equilibrium potentials under neutral conditions (Figure 9c). The engineered mesopores facilitate oxygen enrichment and establishes self‐regulating microenvironments via localized pH modulation, steering the oxygen reduction reaction exclusively toward the two‐electron pathway. In addition, strong interfacial interactions between the carbon framework and metallic nanoparticles optimize critical intermediate adsorption energetics, effectively suppressing competing four‐electron processes. The results highlight the importance of carrier engineering, where mesostructures contribute to the creation of favorable microenvironments and enhance the synergy between active sites. Furthermore, mesoporous electrocatalysts attract much attention due to the highly opened pore structure, which accelerates mass transport. Ma et al. have developed two‐dimensional mesoporous nitrogen‐doped carbon nanosheets with atomically dispersed nickel sites through interfacial molecular assembly for industry‐level electrocatalytic CO₂ (Figure 9d) [118]. In this case, the interconnected mesoporous network can ensure full exposure of single atom sites and enable rapid mass transport at high operational current density. It provides inspiration for overcoming conventional limitations in gas‐liquid‐solid triphasic electrochemistry through synergistically enhanced CO₂ accessibility and efficient desorption of reaction products. Notably, the mesoporous catalyst provides an internally confined space that can selectively encapsulate active sites at different spatial locations. For instance, Zhang et al. have presented a spatially compartmentalized dual‐metal catalyst system loaded with both copper and ruthenium nanoparticles on a N‐doped ordered mesoporous carbon framework (Figure 9e) [119]. The mesostructure enables precise topological segregation with copper clusters confined within the mesochannel interiors, facilitating the rapid conversion of nitrate to nitrite. Meanwhile, ruthenium sites anchored on the external surface generate reactive hydrogen species, which diffuse through interconnected porosity to further drive the subsequent ammonization. It demonstrates that mesoporous space can create a platform that integrates multifunctional components without interference, enabling an ordered and cascaded chemical reaction process.

Photocatalysis is gaining significant attention as a promising solution to the growing challenges in the field of energy and environment. Mesoporous TiO₂ is an ideal photocatalyst due to its natural abundance, environmental benefits, and stability. For example, Lan et al. have developed radially cracked TiO₂ microspheres with interconnected macro‐mesopores, enabling rapid reactant penetration and efficient photon harvesting across hierarchical surfaces (Figure 9f) [70]. This structure can directly circumvent mass transport bottlenecks during photochemical transformation process, resulting in a high hydrogen production rate under solar light. Besides morphology and mesostructure, production of defects, modulation of crystal structure, and doping are also effective ways to improve photocatalytic performance. Phase junction structures are widely recognized for preventing the reassociation of photogenerated charges and holes, which in turn enhances both quantum efficiency and photocatalytic performance. Zhang and coworkers have created phase interfaces of anatase and rutile within mesoporous frameworks, which spatially separated photogenerated electrons and holes, thereby preventing their recombination (Figure 9g) [66]. Additionally, this TiO₂ catalyst, engineered with defects, can modulate its electronic structure, enhancing visible‐light response without sacrificing carrier mobility. As a result, the microspheres exhibit an enhanced H₂ generation rate compared to those with a single‐phase structure. Overall, the unique structural characteristics of mesoporous materials, including their high surface areas and tunable pore sizes, provide significant advantages in photocatalysis by enhancing reactant accessibility and facilitating charge transfer. These properties make mesoporous materials a promising platform for the development of next‐generation photocatalysts with improved performances.

6.2. Energy Storage

Mesoporous materials are widely used in rechargeable batteries and supercapacitors. Their relatively large pore sizes facilitate the rapid transport of ions and electrolytes, thereby achieving high performance at high current densities. Moreover, the mesostructure and large pore volume help alleviate volume expansion and stress during electrochemical storage processes, making them suitable for accommodating electroactive guests to improve their cycling stability.

Mesoporous materials can be widely used as a host for active materials. For example, sulfur and iodine are often incorporated into the mesopores as cathodes, while silicon, phosphorus, and metals (lithium, sodium, potassium, and zinc) are used for anodes (Figure 10a). Typically, these active materials can be encapsulated within the host mesoporous channels by various methods such as vapor deposition, melt casting, and electroplating, resulting in composite electrodes. Notably, the mesochannels play a crucial role in confining reaction intermediates, such as polysulfides and polyiodides, which helps to mitigate the shuttle effect. Additionally, the mesopores offer enough space to accommodate the significant volumetric expansion that occurs during the conversion process. By anchoring active sites in the mesoporous channels, the electrochemical conversion reactions can be significantly enhanced, improving the overall kinetics.

FIGURE 10.

Mesoporous materials in energy storage applications. Rechargeable batteries: (a) Preparation of composite electrode by loading active composition in mesopore, (b) Constructing ion diffusion pathway, (c) Artificial ion channels for enhancing ion diffusion and selective ion transport, (d) Mesochannels as redistributor for homogenizing ion flux. Supercapacitors: (e) Providing high surface area and unique ion diffusion pathway for electrochemical double‐layer capacitor (EDLCs) and pseudocapacitors.

Mesoporous insertion‐type anodes take advantage of architecturally ordered porosity to overcome the inherent limitations of bulk materials. For example, Wang et al. have developed a molecular design strategy for fabricating mesoporous Li₄Ti₅O₁₂, in which ultrasmall nanocrystals are inlaid into the carbon frameworks (Figure 10b) [50]. The tailored pore channels not only expose abundant electrochemical active surfaces but also establish ion diffusion pathways at the nanoscale. In addition, the mesopore structures also help to mitigate lattice strain during the cycling process. As a result, the mesoporous Li₄Ti₅O₁₂ exhibits excellent rate and cycling performance compared to the bulk sample.

Efficient ion transport and uniform ion distribution are critical in batteries using metal as the anode. In this regard, mesoporous materials, with their tailored pore structures, provide an ideal platform for controlling these processes. Recently, Ai et al. have constructed a biomimetic solid electrolyte interphase (SEI) through the assembly of pre‐synthesized two‐dimensional mesoporous polydopamine (mPDA) platelets (Figure 10c) [120]. By mimicking the “brick‐and‐mortar” structure of nacre, the SEI exhibits high mechanical robustness. The hexagonally aligned mesochannels in SEI can act as efficient ion transport pathways. Importantly, the mesopores not only homogenize ionic flow but also facilitate desolvation kinetics and selectively sieve cations through surface‐bound hydroxyl and amine groups. This biomimetic SEI helps suppress parasitic reactions and ensures uniform metal deposition, contributing to the stability of the metal anode. Similarly, Wang et al. have achieved stepwise optimization of zinc ion desolvation and transport by constructing Janus mesoporous channels, in which one part is hydrophilic, and the other is hydrophobic [121]. The hydrophilic region preferentially captured zinc ion hydrate clusters, while the hydrophobic region accelerated the desolvation process. The synergy of the two regions can overcome traditional kinetic limitations and significantly enhance the stability and reactivity of the Zn anode. Besides, it is also applicable for protecting lithium metal. Yu et al. have achieved a uniform lithium flux by creating parallel‐aligned mesoporous MgO nanosheets on the lithium anode, which re‐distributes the lithium ions flux, accelerated ion diffusion and resulted in improved reversible lithium plating and stripping (Figure 10d) [122].

Supercapacitors have attracted much attention because of their high power density and excellent cycling stability, which can be categorized into electrochemical double‐layer capacitors (EDLCs) and pseudocapacitors. EDLCs store energy through ion adsorption and desorption at the interfaces of electrolyte and electrode, while pseudocapacitors store energy via Faradic redox reactions. Mesoporous materials with large pore sizes and high surface areas can significantly enhance the performance of EDLCs by increasing ion accumulation and improving the dynamics of charge transfer.

In EDLCs, the capacitance is directly related to the surface area of the electrode. Mesoporous carbons are ideal electrodes for energy storage due to their high surface area and nanoscale mesochannels (Figure 10e). Larger pores in mesoporous materials enable better electrolyte immersion and faster ion diffusion, resulting in better rate capability [14]. Additionally, the presence of micropores within mesoporous walls increases the surface area for charge storage to improve performance [123]. The pore structure is crucial in optimizing EDLCs performance, but further studies, potentially combining machine learning, are needed to deeply unveil the full impact and mechanism.

Pseudocapacitance offers higher capacitances compared to EDLCs, which is associated with Faradaic reactions at the interface of the electrode and electrolyte. However, pseudocapacitor electrodes often suffer from lower power density and shorter cycle life due to poor conductivity, stability, and slow reaction kinetics. To overcome the limitations, several mesoporous electrodes (oxides, carbides, and sulfides) and heteroatoms‐doping carbons have been designed and prepared. These materials exhibited substantial improvements in capacitance, rate performance, and cycle stability compared to bulk counterparts. Furthermore, the connectivity of the pores is also crucial for improving performance. For example, Xia et al. have developed vertically aligned MXene electrodes that exhibit excellent pseudocapacitive performance even at a high scan rate of 2000 mV s⁻¹. This can be attributed to the vertically aligned mesopores, which greatly reduce the path tortuosity of electrolyte ions, facilitating faster ion diffusion and improving rate capability [124]. Besides, internal accessibility of mesoporous particles can be tuned by controlling the orientation of nanochannels. Park et al. have demonstrated that perpendicular mesochannels in open‐end mesoporous carbon spheres (oe‐MCS) exhibit enhanced K⁺ adsorption capacity, shortened K⁺ diffusion length, and improved ion transport compared to closed‐end counterparts with parallel mesochannels [125]. As a result, the resulting oe‐MCS anode exhibited a maximum energy density of 103 Wh kg⁻¹ and a power density of 12 300 W kg⁻¹. Despite significant advancements, the development of supercapacitors with simultaneously high power and energy densities remains essential to address their limited energy storage capacity and short discharge duration.

7. Conclusion and Perspective

In summary, synthesis of mesoporous nanomaterials via the MMDA strategy has gained increasing interest because of its precision, simplification, and functional diversification. Based on this strategy, researchers have proposed a novel assembly mechanism by decoupling the traditional assembly process into several stages, such as the formation of monomicelles, the assembly of monomicelles with precursors, and the controllable assembly of composite monomicelles. Therefore, it is very versatile for the synthesis of mesoporous nanomaterials with diverse morphologies, including nanospheres, 2D nanosheets, 1D nanofibers, core‐shell nanostructures, Janus nanostructures, etc. Benefiting their unique structural characteristics, mesoporous nanomaterials exhibit great potential in catalysis, energy storage, and conversion. However, challenges such as large‐scale synthesis, long‐term material stability, and cost efficiency in practical applications remain to be addressed, requiring interdisciplinary collaboration and technological innovation to drive breakthroughs from fundamental research to industrial applications.

Understanding the formation, evolution, and controlled assembly of monomicelles remains a key scientific challenge in constructing mesoporous nanomaterials. The construction process involves two self‐assembly procedures: the initial modulation of surfactant micellization and the dynamic interfacial interactions between monomicelles and functional species. Advanced electron microscopy techniques have allowed for the direct imaging of the formation of monomicelles, revealing their morphology and spatial structure. However, tracking the real‐time reorganization of atomic or molecular bonds, as well as the dynamic assembly of monomicelles in solution, remains a significant challenge. This difficulty arises from the instability of soft monomicelles, which can easily disintegrate under even slight external disturbances. As a result, traditional methods are unable to capture the transient intermediates during these processes. There is a need for advanced in situ and dynamic characterization techniques to understand the reaction mechanisms, as self‐assembly occurs in a complex system with changing parameters. Emerging techniques, such as in situ small‐angle X‐ray scattering (SAXS) and environmental transmission electron microscopy (ETEM), offer new opportunities to elucidate the processes of monomicelle formation, functional unit assembly, and mesostructure evolution with greater precision.

Regarding the assembly method of monomicelles, the interfacial‐oriented assembly strategy of composite monomicelles, has opened a new paradigm for constructing integrated functional mesoporous materials. The core idea is analogous to the modular design concept of “LEGO bricks”, where precise control over the interactions between monomicelles enables the synthesis of mesoporous materials with specific needs. However, barriers remain in quantitatively describing the cooperative interactions between multiple monomicelles, which requires further development of in situ real‐time characterization methods to reveal cross‐scale assembly mechanisms. In the future, it is expected that experimental parameters (such as temperature and interfacial tension) would be combined with theoretical simulations and machine learning to facilitate the reverse design of mesoporous nanomaterials. As a result, it can revolutionize the trial‐and‐error approach, achieving on‐demand design of mesoporous nanomaterials. For example, mesoporous nanomaterials with clear heterogeneous interfaces (such as p‐n junctions) can be constructed by arranging composite monomicelles with different functions in specific geometric patterns, thus demonstrating unique advantages in photovoltaic conversion and flexible electronic devices.

Furthermore, understanding the complex relationships and underlying mechanisms between structure and properties in mesoporous materials is crucial for improving their functional performance. In mesochannels, pore confinement effects and dynamic host‐guest interactions significantly influence the physicochemical behavior of molecules or ions. Specifically, molecular diffusion within mesochannels differs significantly from bulk‐phase transport due to the combined effects of pore geometry and surface chemistry. Moreover, hierarchical ordered mesoporous structures enable precise modulation of mass transport energy barriers, thereby enhancing ion migration kinetics in energy storage devices or substrate enrichment efficiency in catalytic processes. In addition, nanoconfinement further alters electronic structures and surface energetics, inducing adsorption reconfiguration and reaction pathway selectivity. For instance, in gas separation applications, rationally designed functional groups on mesoporous frameworks achieve selective molecular recognition through electrostatic complementarity and steric hindrance effects.

Author Contributions

All authors contributed to this work.

Conflicts of Interest

The authors declare no conflicts of interest.

Data Availability Statement

The authors have nothing to report.