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. 2025 Nov 3;4(2):165–172. doi: 10.1021/prechem.5c00094

Facile One-Pot Block Copolymer-Mediated Solvothermal Approach for Synthesis of High-Entropy Alloy with Enhanced OER Activity

Binod Raj KC †, Shin-ichi Yusa ‡, Bishnu Prasad Bastakoti †,*
PMCID: PMC12933503  PMID: 41756613

Abstract

Herein, we introduce a straightforward synthesis approach for highly active dendritic multimetallic high-entropy alloy (DMHEA@PtIrPdAgRu) nanoparticles with sufficient entropic mixing, featuring uniform distribution of five noble group metals (Pt, Ir, Pd, Ag, and Ru) via a block copolymer-mediated one-pot solvothermal reduction method for oxygen evolution reaction (OER). In this synthesis, N,N-dimethylformamide (DMF) is used as a reductant as well as solvent and core–shell-corona-type (poly­(styrene)-block-poly­(vinylpyridine)-block-poly­(ethylene oxide)) (PS-PVP-PEO) block copolymer as a structure directing agent. The cooperative effect between the copolymer architecture and the reducing environment of DMF promoted a confined nucleation mechanism for forming a single-phase dendritic structure HEA with high compositional uniformity, thereby mitigating phase segregation, a common challenge in the synthesis of multimetallic nanoparticles. This prepared DMHEA@PtIrPdAgRu catalyst exhibits a low overpotential of 490 mV to attain a high current density of 100 mA cm–2 with a Tafel slope of 442 mV dec–1 for oxygen evolution. The superior OER performance is attributed to the synergistic cooperation among its active and coordinated metal centers as well as the incorporation of corrosion-resistant metal like platinum.

Keywords: block copolymer, high-entropy alloy, single-phase structure, oxygen evolution reaction, nanoparticles, electrocatalysts

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Introduction

The idea of high-entropy alloy (HEA) materials has been attracting more and more recognition in the field of material science in recent years because of their versatile synthetic routes and tunable chemical and functional properties for a very wide range of applications. − These materials display some unusual properties compared with conventional metals or alloys, like high hardness, yield strength, hydrogen storage capacity, and superconductivity. − The primary objective of high-entropy materials is to maximize the configurational entropy with the intention to minimize Gibbs free energy (ΔG = ΔH–TΔS) by stabilizing the strength and adaptability of the system as well as to acquire unexpected synergistic properties with the incorporation of a large number of elements in their structure. , The existence of a multielemental surface offers various nearby adsorption sites, making it efficient for multistep reactions involving several electron transports. By modifying the alloy stoichiometry, the electronic terrain can be altered depending on particular reactions and types of products. Moreover, HEAs are less prone to poisoning because of their diverse surface elements, which offer alternative binding sites, and some HEAs have shown improved corrosion resistance, enhancing stability in harsh environments.

To date, several synthesis strategies have been documented for high-entropy alloy materials. , Arc/induction melting and sputtering/physical vapor deposition (PVD) methods require high energy consumption. Applications for sputtering/PVD are limited to thin films, while arc/induction melting does not have control over the structure of materials. The carbothermal shock technique requires extremely high temperatures and only depends on a carbon-based substrate. Rapid heating and cooling in this process make it hard to control crystallization and phase formation precisely. Among the various routes of synthesis procedures mentioned above, the solvothermal method is one of the most widely used conventional, simple, and benign solution-based chemical synthetic routes developed for efficient fabrication of high-entropy materials at relatively low temperatures. Usually, synthesis of high-entropy alloys based on the bottom-up wet-chemistry method involves sources of metals to form the alloy, a reducing agent to assist the reduction reaction, a stabilizing/capping agent to prevent aggregation, and an appropriate solvent. The strategic assortment of these essential components, along with their amounts and proportions, contributes to the reduction, nucleation, and growth of nanoparticles. The formation of crystal lattices and elemental combinations primarily depends on the types of solvent used. A broad spectrum of nanoparticles with sizes ranging from a few nanometers to several tens of micrometers can be synthesized by adjusting the synthesis conditions like time, solvent, precursors, pH, stabilizer, and capping agent. Major advantages associated with this process include low cost, straightforward operations, and easily scalable production of high-quality uniform crystalline nanoparticles. In addition, it provides better control over the composition, structure, and purity of materials by minimizing phase separation, which is one of the critical parameters for acquiring the optimal outcomes. Another pivotal advantage of growing high-entropy nanoparticles by the traditional wet-chemistry colloidal solvothermal technique is to capitalize on the long-standing knowledge of controllable nucleation and growth of colloidal nanoparticles over time.

Most of the reported solvothermal synthesis is combined with a reducing as well as capping agent to facilitate the reduction of metal ions in the reaction medium to obtain specific phases. It is well known that N,N-dimethylformamide (DMF) shows dual function, i.e., one as a solvent and the other as a reductant for different metal species. − DMF is widely recognized for having high synthetic value because of its broad range of liquid temperatures, strong thermal and chemical stability (even when it reaches 153 °C, its boiling point), high polarity, and broad range of solubility for both organic and inorganic compounds (e.g., block copolymer, various metal precursors) offer compelling justification for the use of DMF as a solvent and reductant for the synthesis of DMHEA@PtIrPdAgRu. , Mechanistically, a terminal carbonyl group causes reduction of metal ions in the redox reaction when DMF is used. The terminal carbonyl group is oxidized to a carboxylic group by metal ions, while metal ions are reduced to atoms. ,,

Core–shell-corona-type triblock copolymer PS-PVP-PEO composed of polystyrene (PS), polyvinylpyridine (PVP), and poly­(ethylene oxide) (PEO) was utilized as a structure directing micellar agent for the synthesis of a high-entropy alloy. These micelles act as soft nanoreactors, with the PS block forming a hydrophobic core, PEO ensuring additional solubility and colloidal stability in DMF through hydrogen bonding or solvation and its chain flexibility, and PVP coordinating with different metal ions via its pyridine nitrogen functionalities due to Lewis acid–base interactions. It helped in controlling size and dispersion along with the formation of compositional uniformity by homogeneously distributing different metal nanoparticles in a true high-entropy alloy. − The block copolymer also helps to provide a nanoconfined environment for metal ions to coreduce simultaneously within the micellar space, promoting mixing of multiple elements, as well as confined nucleation in micellar domains, which helped to suppress phase separation and uniform distribution of metal atoms by preventing isolated nucleation of individual metals during the solvothermal process and the reducing nature of DMF ensured controlled reduction kinetics. DMF also screens for hydrogen bonding and enthalpic interactions, moderating PVP swelling and enabling controlled micellar architecture. Polymer blends tend to self-assemble into micelles, and DMF also solubilizes both block copolymer and metal precursors and promotes uniform micelle dispersion, along with enabling thermodynamic control during the slow thermally induced reduction in the solvothermal process, allowing the formation of a single-phase alloy at 200 °C. , This synthetic route parallels carbothermal shock or aerosol methods but operates at lower temperatures via colloidal chemistry.

Herein, we introduced a novel one-pot solvothermal synthesis approach for the fabrication of dendritic high-entropy alloy nanoparticles DMHEA@PtIrPdAgRu by simultaneously reducing five distinct noble metal precursors, leveraging the dual role of DMF as both a solvent and a reducing agent and utilizing block copolymer micelles of PS-PVP-PEO as soft templates serving as a versatile scaffold for controlled nanoparticle formation. The cooperative effect between the copolymer architecture and the reducing environment of DMF promoted a confined nucleation mechanism for the formation of a single-phase dendritic structure HEA with high compositional uniformity and mitigating phase segregation, a common challenge in multimetallic nanoparticle synthesis. The block copolymer formed micellar structures that functioned as nanoreactors, with the PVP corona spatially confining multiple metal ions. This confinement facilitated their simultaneous coreduction and uniform alloying, while the reducing properties of DMF enabled controlled reduction kinetics. The prepared catalyst displayed enhanced OER performance with an overpotential of 490 mV to attain 100 mA cm–2 and a Tafel slope of 442 mV dec–1. This method offers a versatile, scalable route to compositionally complex nanomaterials with a tunable architecture, highlighting the synergy of soft templating and solvent-driven reduction in multimetallic nanoparticle synthesis.

Experimental Section

Materials

All of the chemicals were used as supplied by the manufacturers, without undergoing additional purification. The metal precursors employed were Platinum­(IV) chloride (PtCl4, Alfa Aesar, 99.9%), Iridium­(III) chloride (IrCl3·xH2O, Thermo Scientific, 99.8%), Palladium­(II) chloride (PdCl2, Alfa Aesar, 99.9%), silver nitrate (AgNO3, Fisher Chemical, 99.9%), and Ruthenium­(III) chloride (RuCl3, Thermo Scientific, 99.9%). The block polymer poly­(styrene)-block-poly­(vinylpyridine)-block-poly­(ethylene oxide) and PS(20100)-PVP(14200)-PEO(26000) were obtained from Polymer Source. The numbers inside the parentheses indicate the molecular weight of each block. Additional chemicals used were N,N-dimethylformamide (DMF) (C3H7NO, Fisher Bioreagents), ethanol (C2H6O, Sigma-Aldrich, 95%), acetone (C3H6O, Fisher Chemical, 99.5%), N-methyl-2-pyrrolidone (NMP) (C5H9O, Alfa Aesar, 99.5%), poly­(vinylidene) fluoride (PVDF) (Aldrich), carbon cloth (Fuel Cell Earth), and sulfuric acid (H2SO4, Fisher Chemicals, 98%). Throughout all stages of the experimental procedure, including material synthesis, washing, and electrochemical measurements, deionized water was used.

Synthesis of Dendritic Multimetallic High-Entropy Alloy

Noble metal-based dendritic multimetallic high-entropy alloy nanoparticles (DMHEA@PtIrPdAgRu) were synthesized via an economical and facile core–shell-corona-type block copolymer-assisted one-pot solvothermal reduction technique. 50 mg of PS-PVP-PEO polymer was completely dissolved in DMF, forming a transparent solution. Five different metal precursors (in equimolar ratios) were added to it and completely dissolved with the aid of magnetic stirring for 3 h and transferred to a Teflon steel autoclave. Here, metal ions coordinate with the PVP block of the triblock copolymer. The autoclaves containing the solution were placed in an oven and started heating slowly until 200 °C, and it was aged for 20 h at 200 °C. Here, thermal reduction induces nucleation where various metals coreduce simultaneously with growth proceeding confined within a micelle, resulting in the formation of a single-phase DMHEA@PtIrPdAgRu. After the completion of heating, the autoclave was cooled to room temperature. The solid fraction obtained was collected by centrifugation and washed with ethanol/acetone several times. The obtained nanoparticle powder was dried in a vacuum oven at 60 °C for 24 h. For comparison, a high-entropy alloy (HEA@PtIrPdAgRu) without PS-PVP-PEO was also synthesized via the same method. A schematic illustration of the synthesis procedure of DMHEA@PtIrPdAgRu nanoparticles is displayed in Figure a.

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(a) Schematic illustration of block copolymer-mediated synthesis of DMHEA@PtIrPdAgRu via solvothermal reduction, (b) SEM image of DMHEA@PtIrPdAgRu nanoparticles, (c) TEM image of a single DMHEA@PtIrPdAgRu, (d) particle size distribution curve, (e) HRTEM, (f) corresponding plane set as inferred from (e), and (g) SAED pattern of DMHEA@PtIrPdAgRu.

Material Characterizations

The analysis of structural and morphological characteristics was carried out using field emission scanning electron microscopy (FE-SEM) equipped with energy-dispersive X-ray spectroscopy (EDS), specifically the JEOL JSM-IT800 Schottky instrument. Additionally, a 200 kV transmission electron microscope (TEM) with an EDS facility, model Talos F200X, was employed for the detailed analysis of bulk topography. Crystallographic structures of the sample were characterized by using X-ray diffraction (XRD) analysis using a Rigaku MiniFlex 600 with Cu Kα at a wavelength of 1.5406 Å. Fourier transform infrared (FTIR) spectroscopy of model IRT racer-100 was utilized to characterize the polymer and the prepared sample. The elemental composition and chemical bonding states of the sample were analyzed by using a Kratos Axis Supra X-ray photoelectron spectroscopy (XPS) system.

Preparation of Electrodes and Electrochemical Measurements under a Three-Electrode System

Electrochemical characterization of the fabricated electrodes was conducted using a BioLogic VSP potentiostat. The DMHEA@PtIrPdAgRu, HEA@PtIrPdAgRu, and commercial RuO2 were employed as working electrodes, each with a defined geometric surface area of 1 cm2. Platinum wire and an Ag/AgCl electrode were employed as counter electrode and reference electrode, respectively, to ensure accurate potential control and measurement stability throughout the experiments. The working electrode ink was prepared by dispersing the electroactive material and poly­(vinylidene fluoride) (PVDF) binder in a 90:10 weight ratio using N-methyl-2-pyrrolidone (NMP) as the solvent. The mixture was subjected to sonication for 1 h to ensure homogeneity. The resulting ink was subsequently coated onto a carbon cloth substrate with a geometric area of 1 cm2, maintaining a catalyst loading of 2 mg/cm2. All of the electrochemical measurements were conducted in a three-electrode setup with nitrogen saturation in 0.5 M H2SO4. In this study, all of the electrochemical potentials were converted to the reversible hydrogen electrode (RHE) scale using the equation: E (vs RHE) = E (vs Ag/AgCl) + 0.198 + 0.059 pH. For a 0.5 M H2SO4 electrolyte, pH values are equal to 0.

Results and Discussion

To gain a detailed understanding of the surface morphology of DMHEA@PtIrPdAgRu, field emission scanning electron microscopy (FE-SEM) was used on the samples. The SEM image of DMHEA@PtIrPdAgRu is displayed in Figure b. The synthesized sample exhibits a dendritic spherical nanoparticle morphology. The hydrophilic micelle in the outer layer of PS-PVP-PEO interacts with metal ion complexes, drawing them in and keeping them concentrated at the micelle surface. This results in localized regions rich in metal ions that serve as favored sites for nucleation. Thus, micelles effectively direct and control the nucleation process by providing targeted areas where crystal growth can start. The morphology of a high-entropy alloy synthesized without using block copolymer HEA@PtIrPdAgRu is shown in Figure S1, which shows irregular agglomerated nanoparticles without any well-defined geometric features. This morphological disorder highlights the pivotal function of the block copolymer as the structure directing agent, facilitating the controlled nucleation and growth process to achieve uniform dendritic morphology in synthesized DMHEA@PtIrPdAgRu nanostructures. The elemental percentage distribution of HEA@PtIrPdAgRu and DMHEA@PtIrPdAgRu obtained via FE-SEM-energy-dispersive X-ray spectroscopy is displayed in Figure S2. To further visualize the atomic-level internal crystal lattice structure, high-resolution transmission electron microscopy (HRTEM) was performed. The HRTEM image of DMHEA@PtIrPdAgRu is displayed in Figures c and S3. The prepared dendritic nanoparticles have a particle size distribution of ≈90 ± 5 nm (Figure d). The HRTEM image adjacent to the edges (Figure e) demonstrates a crystalline nature with distinct visible lattice fringes. An inverse fast Fourier transform (FFT) pattern was generated by processing a different selected region of the HRTEM image from Figure e to extract lattice fringe patterns as shown in Figure f. The result of associated interplanar spacings revealed the presence of (111), (200), (220), and (311) crystallographic planes with lattice spacing of approximately 0.22, 0.19, 0.14, and 0.12 nm, respectively. These values comply with typical values for the face center cubic (FCC) platinum (Pt) crystal system. , The polycrystalline nature of DMHEA@PtIrPdAgRu was confirmed by selected area electron diffraction (SAED) patterns, as displayed in Figure g. The observed concentric diffraction rings composed of well-defined, discrete spots are characteristics of a polycrystalline structure, which is indexed to an FCC phase, affirming the existence of multiple crystalline domains within the material. Based on overall TEM and SAED analysis, DMHEA@PtIrPdAgRu nanoparticles appeared to be crystallized in an FCC single phase. Furthermore, energy-dispersive X-ray spectroscopy (EDS) coupled with high-angular dark-field scanning transmission electron microscopy (HAADF-STEM) was employed to elucidate the spatial distribution of elements in the DMHEA@PtIrPdAgRu system (Figure a,b). The analysis of representative nanoparticles confirms the uniform incorporation of Pt, Ir, Pd, Ag, and Ru across the entire nanostructure.

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(a, b) HAADF-STEM-EDS image and respective elemental maps of Ir, Pd, Pt, Ru, and Ag in DMHEA@PtIrPdAgRu, respectively.

To analyze the crystallographic structure of DMHEA@PtIrPdAgRu, powder X-ray diffraction (XRD) was conducted, which is displayed in Figure a. The powder XRD pattern confirms that the DMHEA@PtIrPdAgRu multimetallic nanoparticles adopt a FCC crystal lattice system, as demonstrated by five distinct diffraction peaks located at 2θ values of 39.61, 46, 67.12, 81, and 85.43°, which can be indexed to the (111), (200), (220), (311), and (222) crystallographic planes, respectively. , These characteristics of diffraction features are consistent with the structural information obtained from transmission electron microscopy (TEM) analysis (Figure ). The absence of separate diffraction signals associated with individual metals Pt, Ir, Pd, Ag, and Ru or their oxides forms confirms the formation of a single-phase alloy, indicating uniform elemental distribution, with no evidence of phase segregation or impurity phase. , A slight shift in the XRD peaks of DMHEA@PtIrPdAgRu and a decrease in d-spacing indicate the incorporation of more metals and resulting high entropy into the alloy system. , The Fourier transform infrared (FTIR) spectrum of PS-PVP-PEO triblock copolymer (Figure b) used for the synthesis of DMHEA@PtIrPdAgRu shows characteristic peaks corresponding to each constituent block, which confirms its structural integrity (wavenumber with corresponding assignment of various FTIR spectra is given in Supporting Information Table S1). The final product of DMHEA@PtIrPdAgRu recovered by multiple centrifugations washed with ethanol and acetone revealed removal of the polymer as confirmed by FTIR analysis (Figure b).

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(a) XRD pattern of DMHEA@PtIrPdAgRu with inset FCC structure, and (b) comparison of FTIR spectra of bare PS-PVP-PEO and DMHEA@PtIrPdAgRu after solvent extraction.

To analyze the local structure, chemical state, and composition of DMHEA@PtIrPdAgRu nanostructure, surface-sensitive X-ray photoelectron spectroscopy (XPS) was performed. The distinct and well-defined spectral peaks corresponding to Pt, Ir, Pd, Ag, and Ru (Figure S4) demonstrate multielemental composition on the surface, highlighting successful integration of these elements into the surface region, consistent with compositional complexity expected of HEA. The cocktail effect and intrinsic chemical disorder result in highly interatomic interactions and electronic hybridizations among neighboring atoms, which alter the local electronic environment, causing a shift in the core energy levels of the atoms (Figure S4). −

This rationally engineered multicomponent electrocatalyst aims to mitigate intrinsic challenges associated with RuO2, specifically its limited stability and catalytic inefficiency when operating in acidic media. Electrochemical water splitting plays a crucial role in sustainable energy conversion by generating hydrogen and oxygen, which have the potential to replace traditional fossil fuels with green alternatives that leave a zero carbon footprint. This study presents a strategic way to rationalize the design of high-performance OER electrocatalysts by harnessing the synergistic interplay among multiple elements. Oxygen evolution from water in acidic environments is kinetically sluggish due to its involvement in four-electron-transfer mechanisms with multiple high-energy intermediates and significant activation barriers. Consequently, the strategic design and synthesis of highly efficient catalysts tailored specifically for OER is critically important for advancing energy conversion technologies. , High-entropy alloys, featuring a multitude of distinct active sites that collectively offer a near-continuous range of adsorption/desorption energies, emerge as highly promising catalytic materials. These attributes facilitate optimal binding energy and release of intermediates for efficient OER. Here, the OER activity of DMHEA@PtIrPdAgRu and HEA@PtIrPdAgRu samples was systematically investigated and benchmarked with commercial RuO2 to elucidate the synergistic effect of multimetallic incorporation on catalytic performance. OER measurements for all samples were performed in a 0.5 M H2SO4 electrolyte using a standard three-electrode system under ambient conditions, with all electrode potentials calibrated against the reversible hydrogen electrode (RHE). Before the LSV test, cyclic voltammetry (CV) was performed by cycling the electrode between −0.1 and 1.5 V vs RHE to activate the electrocatalyst–electrolyte interface. The resulting CV of DMHEA@PtIrPdAgRu at different sweep rates is displayed in Figure a, which exhibits higher activity as compared with HEA@PtIrPdAgRu and commercial RuO2 (Figure S5). Figure b shows a comparison of polarization curves for different electrocatalysts conducted at a sweep rate of 10 mVs–1. As displayed in the linear sweep voltammetry (LSV) curve, DMHEA@PtIrPdAgRu achieves much higher OER activities among all other samples. It has the lowest overpotential of 490 mV vs RHE to reach a current density of 100 mA cm–2, in comparison to other samples where commercial RuO2 requires 540 mV and HEA@PtIrPdAgRu requires 610 mV to reach 100 mA cm–2. These results demonstrate the superiority of DMHEA@PtIrPdAgRu over commercial RuO2, which was regarded as a state-of-the-art catalyst for OER. The incorporation of corrosion-resistant metals like platinum and ruthenium is attributed to the high performance and durability of DMHEA@PtIrPdAgRu in OER by lowering the overpotential. Multielement interactions in it maintained a strong metal–metal bonding with an intact structure during OER operational stress, resulting in improved electrocatalytic activity under acidic settings. The Tafel slope was thoroughly analyzed to obtain a more comprehensive understanding of the underlying kinetics of oxygen evolution. The Tafel slope analysis (Figure c) clearly indicates that the DMHEA@PtIrPdAgRu catalyst exhibits a remarkably smaller Tafel slope of 442 mV dec–1 among the other samples investigated. This significantly lower value of Tafel slope as compared with HEA@PtIrPdAgRu (588 mV dec–1) and commercial RuO2 (459 mV dec–1) highlights the superior intrinsic catalytic activity of the DMHEA@PtIrPdAgRu system due to enhanced reaction kinetics, reduced energy barriers, and more efficient charge transfer, which can be attributed to the synergistic effect of multimetallic composition and optimized electronic structure. ,, The enhanced electrocatalytic performance of DMHEA@PtIrPdAgRu was also attributed to higher electrochemical double-layer capacitance (Cdl) along with high electrochemically active surface area (ECSA) values, which was determined from CV curves in the non-Faradaic region at various scan rates (Figure S6). Table S2 summarizes and compares the Cdl and ECSA values for the prepared HEA electrocatalysts. The accelerated reaction kinetics of DMHEA@PtIrPdAgRu was further validated through electrochemical impedance spectroscopy (EIS) analysis (Figure S7), in which it showed a substantially lower charge transfer resistance of 0.0641 Ω compared with HEA@PtIrPdAgRu (0.118 Ω) and commercial RuO2 (1.053 Ω). This notable reduction in charge transfer resistance clearly indicates improved conductivity and more efficient electron transfer at the electrode–electrolyte interface, showing faster electrochemical reaction in a multimetallic system. , High configurational entropy within the HEA system facilitates the stabilization of a homogeneous single-phase solid solution by suppressing the phase separation as well as the formation of a secondary phase. , As a result, HEA exhibits enhanced structural integrity resulting in improved alloy structure against corrosion and dissolution under harsh acidic conditions due to its multielement composition and unique high entropy state, resulting in enhanced OER activity. The stability of the catalyst was assessed through a chronopotentiometry test, which was carried out to monitor the potential response under a constant current density of 10 mA cm–2 for a duration of 10 h (Figure S8). The results demonstrated the good durability of DMHEA@PtIrPdAgRu at a lower overpotential as compared with that of commercial RuO2. The good stability of DMHEA@PtIrPdAgRu could be attributed to strong stabilization and diffusion resistance of multimetallic matrix along with the stable crystallinity that prevented etching and metal separation.

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(a) Cyclic voltammetry of DMHEA@PtIrPdAgRu, (b) OER polarization curves, (c) Tafel slope plot, and (d) overpotential graph at a current density of 100 mA cm–2 for DMHEA@PtIrPdAgRu, HEA@PtIrPdAgRu, and commercial RuO2.

Conclusion

In summary, we report a facile one-pot block copolymer-assisted solvothermal reduction technique for the synthesis of a highly active dendritic DMHEA@PtIrPdAgRu high-entropy alloy. Block copolymer is utilized as the soft template as a structure directing agent and DMF as a reducing agent and solvent. The prepared DMHEA@PtIrPdAgRu demonstrated the mechanism of self-assembly-driven growth of dendritic architecture via the reduction properties of DMF. The PS-PVP-PEO system in DMF facilitates the formation of a polymer-templated micellar framework that enables the colocalization of diverse metal ions through coordination interactions, followed by their in situ reduction within spatially confined nanodomains. This template-directed assembly strategy governs nucleation dynamics, promotes compositional homogenization, and modulates nanoparticle growth, thereby providing a finely tunable platform for the synthesis of high-entropy alloy nanoparticles via a soft-templated, low-temperature solvothermal approach. Our experimental results showed that DMHEA@PtIrPdAgRu in 0.5 M H2SO4 demonstrated enhanced OER activity with a lower overpotential of 490 mV at 100 mA cm–2 and a Tafel slope of 442 mV dec–1. The enhanced electrocatalytic performance of DMHEA@PtIrPdAgRu was due to a synergistic cooperative effect originating from all of the active metal sites along with coordinated metals rather than the actions of distinct metals. Our study paves the way for designing diverse multifunctional HEA by utilizing block copolymers with tunable morphologies and structures for a wide range of applications.

Supplementary Material

pc5c00094_si_001.pdf (1.3MB, pdf)

Acknowledgments

This research was supported by the Department of Energy through the Center for Electrochemical Dynamics and Reactions on Surfaces under Grant DE-SC0023415.

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/prechem.5c00094.

  • SEM images, SEM-EDS spectra, TEM images, FTIR peaks assignment table, XPS spectra, CV, current density vs scan rates plot, Cdl and ECSA table, Nyquist plot, and stability curve (PDF)

The authors declare no competing financial interest.

Published as part of Precision Chemistry special issue “Precision Chemistry for High Entropy Nanomaterials.”

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