CO₂ Sequestration: A Global Challenge toward Future Opportunities

Abstract

The pursuit of atmospheric net-zero CO₂ emissions has become a global priority among scientific communities, industries, and policymakers in response to escalating climate change challenges. Despite significant advances in carbon capture, sequestration, and utilization technologies, major challenges remain regarding capture efficiency, energy requirements, economic feasibility, and long-term environmental benefits of existing approaches. Although CO₂ is seen as a global threat, it is an important source of chemical materials that should be mitigated in the path of materials synthesis. This Review critically examines current limitations in CO₂ sequestration and reduction technologies while highlighting emerging pathways for the sustainable utilization of captured CO₂. Furthermore, the Review introduces a carbon destiny framework that evaluates CO₂ management strategies based on carbon permanence, value creation, circularity, transformation complexity, and long-term environmental impact.

Introduction

Overview of the Global CO₂ Emissions

An increased atmospheric CO₂ concentration has raised global awareness about CO₂ emissions as an important pollutant among other greenhouse gases. It is believed that CO₂ released in the atmosphere increases in an extrapolated manner every year and presents a prominent threat to human health and the environment in particular. This excessive increase of CO₂ emissions drew the attention of the scientific communities and governmental policy makers to reconsider and provide rapid or alternative remediation in response to suppress the global climate-related problems which at the front line implicate the current registered global warming of the Earth. Interestingly, the cumulative rate of the atmospheric CO₂ levels and the consequent global warming are interlinked to the global population’s activities and are argued to be of human origin. This argument is supported by the existing high human demand for various materials/products and utilities for the modern population survival. The major contributing activities led by the global population toward CO₂ emissions include the use and/or processing of natural gas, fuel, oil, coal, chemicals, bioenergy, and waste (Figure ).

1.

Simplified CO₂ emissions from main important sources.

The global dependence on liquid fuels, bulk chemicals, and electricity generation is the origin of a massive exploitation and use of fossil fuels, which remain an inevitable and reliable primary source of liquid fuels and a contributor to the increased CO₂ release. CO₂ indeed is a potentially valuable C₁ feedstock for such liquid fuels and chemicals manufacturing, which should be addressed for sustainable environmental solutions. The grand challenges exist between the development of high-efficiency processes (cost-energy effectiveness) and environmental friendliness to boost the CO₂ capture and chemical conversion processes to a more prominent sustainable practice. The state of the art has revealed many attempts and technologies in the development and depletion of CO₂ capture and conversion; however, large-scale installations of the CO₂ capture and conversion facilities toward valuable materials are scarce, offering a nonoptional sustainable energy economy. Conventional chemical absorption (solvent-based), adsorption (solid–sorbent driven), and membrane separation techniques comprise the current state of the art in CO₂ capture. CO₂ conversion routes comprise thermochemical, biochemical, photochemical, and electrochemical approaches.

First, this Review discusses the accounted drawbacks and barriers of the established current CO₂ capture technologies. Challenges in CO₂ conversion processes are discussed. By linking mitigation strategies with resource utilization pathways, the Review offers a broader framework for understanding an emerging transition from isolated technology development toward integrated carbon-management networks in which renewable energy, carbon capture, sequestration, and utilization (CCSU) operate as interconnected components to contribute simultaneously to climate change mitigation and sustainable industrial implementation. Finally, ideas and perspectives for the development of new techniques and opportunities are highlighted.

CO₂ Capture Techniques

The CO₂-originating source entitles to the corresponding carbon capturing technique. Quietly, capturing CO₂ from industrial emissions known as CO₂ emissions at the point sources largely differs from CO₂ emissions at nonpoint sources in terms of methods and materials used. The most widely commercialized systems used in industrial CO₂ capture involve postcombustion capture, precombustion capture, and oxy-fuel combustion capture. On the other side, capturing CO₂ from flue gas at nonpoint sources known as direct air capture (DAC) is based on absorption in solvents, adsorption into solid adsorbents, filtration using membranes, metal–organic framework (MOFs) adsorbents, and nanoparticle adsorbents.

The balance between the energy-intensive and CO₂ capture efficiency is the biggest challenge in the current carbon capture and utilization (CCU) implementation. Nevertheless, it provides future opportunities to design cost-effective strategies to attain global “net zero” CO₂ emissions. Understandably, any adopted CCU technique resides on a number of operational conditions that could ensure a high selectivity of CO₂ removal in gas mixtures and the reusability of the materials employed in the processes. In the carbon capture processes, CO₂ partial pressures, temperature-swing, and CO₂ concentrations vis à vis energy input are the most determining conditions for an effective commercialized and scalable approach. Therefore, limitations and barriers of the current CO₂ capture systems are extremely imposed by these conditions as is discussed in the corresponding sections.

CO₂ Capturing at the Point Sources

A great deal of effort has been made to reduce CO₂ from the point source emissions from the industrial counterpart with many exceptions to selectively control the CO₂ emissions and other greenhouse gases right before escaping into the atmosphere. Most of the existing techniques are too old to meet the present policies for CO₂ regulations, as proposed by the United Nations Climate Change Conference in 2015. This would imply new insight into reformulation for the existing techniques and innovative techniques well-adapted to the situation of the century. Below here, the existing CO₂ capture techniques at the point sources are provided and discussed for their so far well-known operating principles, advantages, and limitations.

Postcombustion

Unquestionably, the high demand for global thermal energy in modern society exclusively remains a reliable long-term running of thermal power plants known for excessive fuel consumption as the unique feedstock and without ultimate green substitute sources. The postcombustion technique was mainly designed and applied for the majority of thermal power plants generating electricity, which extensively burn fuels in the form of coal or natural gas in the air. Basically, the technique aims at separating CO₂ in a mixture of components primarily CO₂/water vapor and nitrogen (from air) contained in flue gas (Figure ). The advantages of the postcombustion can be linked to the easier applicability of the approach to the old and existing power plants, higher CO₂ separation efficiency from the exhaust gas, and availability of numerous operating routes of preference, including absorption, adsorption, membrane separation, and cryogenic separation. The overall disadvantages of postcombustion CO₂ capture are separation difficulties related to low CO₂ concentration and low pressure of the diluted flue gas, which contains large amounts of nitrogen from the air, simultaneously energy-intensive.

2.

Simplified model of CO₂ capturing techniques at the point sources.

Precombustion

Similarly, the precombustion technique is also designed for separating CO₂ from thermal power plants utilizing fossil fuels on a different pathway. The operating mode of the approach relies on production of syngas composed mainly of a mixture of carbon monoxide, hydrogen, and some carbon dioxide through partial oxidation of fuel under limited oxygen. Therefore, through a steam turbine and a gas turbine, thermal and chemical energy contained in the so-gas mixture is converted into electricity, respectively.

Practically, through simple monitoring and control of the produced syngas, the precombustion system is efficient in generating and separating CO₂ on a preferable operating mode. As such, carbon monoxide can be converted into CO₂ to constitute more CO₂/H₂ mixture, which can easily be separated to produce CO₂ and pure hydrogen in the corresponding separation units (Figure ). Factors influencing a high efficiency and less energy consumption of the precombustion system are linked to a high pressure and high concentration of the CO₂ accumulated in the separation unit rendering this approach more advantageous than the postcombustion. However, power plants cannot be retrofitted on their old status to meet the new requirements in the CCU, besides pure oxygen supply difficulties.

Oxy-Fuel Combustion Capture

This approach targets separating the products of fuel combustion in pure oxygen, mainly flue gas containing CO₂ and water vapor. Attached to its simplicity and high efficiency, CO₂ is separated from water vapor through condensation (Figure ). Through controlled recirculation of flue gas flowing in the maintained oxygen supply, the operating system is improved and can be more energy-efficient.

The advantages of this technology are associated with a high collection of CO₂ concentration and the ease of operating the facility. However, nowadays, the technology does not find an engineered application and can meet a supply shortage of pure oxygen in large quantities.

CO₂ Capture at Nonpoint Sources

The important CO₂ emissions can be perceived from nonpoint sources, which constitute a non-negligible portion of emissions from car exhaust gases, natural forest burning, and domestic activities that release CO₂ directly into the air without prior-capturing conditions. The only way to mitigate such emissions can be addressed by direct capture from the environment, which necessitates strong and efficient technologies.

Unlike CO₂ capture at the point sources, capturing CO₂ emissions directly into the environment can meet several technical challenges, some of which are related to a very low CO₂ concentration in the air and others related to low pressure, thereby imposing a high operational energy cost.

The scientific community has worked tirelessly to address the emerging and improved potential techniques, where some of them are solvent-dependent and others are sorbent-dependent. Solvent-dependent though could be simple to operate, however, it could result in low efficiency in terms of low CO₂ uptake, CO₂–solvent separation, CO₂ storage, and CO₂ conversion difficulties. Additionally, it could present a secondary type of environmental pollution at the expense of the recyclability and reusability of the used solvents. Besides, solvent-based absorption could have a limited number of applications in an open-air space. Technically, substantial operational facilities and related costs could be required for such solvent-based technology to be well applied in outdoor CO₂ reduction environments. Conversely, solid-based sorbent approaches could have an easy application in the environment and on equipment producing emissions as well. However, their formulations need to be tailored and designed to boost a very specific type of application as will be discussed below.

CO₂–Solvent Capture Approach

The chemical ability of alkali absorbent solutions to combine with CO₂ has shaved a path toward CO₂ separation from a mixture of gases by forming carbamate or bicarbonate salts. The so-called CO₂ capturer moieties from aqueous solutions can then be heated at a very specified temperature in appropriate equipment such as a reboiler to release the stored CO₂ (in the form of carbamate) and regenerate the solvent. Theoretically, the working principle is quite simple and efficient because the solvent can be exposed to contact with the gaseous mixture through pipeline channels and selectively absorb the CO₂ from the mixture at low pressure and temperature conditions. The accounted limitations of the absorption by solvents are directly attached to the chemical properties, regeneration capacity of the solvent, and the retention stability of the absorbed CO₂ which vary upon the type and properties of the solvent employed. For instance, corrosive nature , and a high energy cost of desorption of the amine-based moieties such as monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine (MDEA), and 2 - amino-2-methyl-1-propanol (AMP) handicap the commercial applications, though these substances have a high affinity to CO₂ reaction. Moreover, the instability of these primary/secondary amines to form stable carbamates by reacting with the absorbed CO₂ was reported, resulting in the formation of bicarbonates. It is worth noting that tertiary amines cannot form carbamates upon CO₂ contact and therefore are not employed in the CCU. Merely, the stored CO₂ in the form of carbamate or bicarbonate salts via this technology has a limited number of applications for materials syntheses.

Physisorption technology operating at the dissolution ability of the CO₂ in the solvent could be less demanding in terms of solvents regeneration and energy intensive; however, it has fewer commercial applications generally attributed to high viscosity and high vapor pressure leading to less CO₂ mass transfer in the absorbent and loss of solvent, respectively. Therefore, there exists a weak interaction between the physical solvents and the targeted CO₂ gas. Commonly used solvents in this category include methanol, polyethylene glycol dimethyl ether (Selexol), N-methyl-2-pyrrolidone (NMP), and propylene carbonate. ,

Another important class of materials consists of POPs which could have superior characteristics toward the highest selectivity and stability of CO₂ enhanced by the presence of tailored porous channels. POPs could have a promise of CO₂ reduction toward syngas production with high selectivity. Yet, POPs are still being employed in aqueous solutions with imine-based composition to become a green approach.

Fundamentally, amine-based CO₂-solvent-capturing techniques have shown main challenges that seem to impede their practical scalability. The instability at high desorption temperature releases further undesirable gases such as ammonia and HCl into the atmosphere, along with the target CO₂, because of concurrent solvent degradation. In addition, low CO₂ collection and a limited number of transformation pathways to product manufacturing remain an important point of discussion about the future of solvent-based CO₂ reduction mitigation.

Solid Sorbent Systems

In response to the limitations of using liquid amines, solid materials have extensively been explored for their capabilities of reversibly absorbing and releasing CO₂ with the high stability of the formed intermediate products and low energy cost. There exist preferable features of sorbents over those of other materials used in CCUS. These features include (i) high selectivity of sorbents toward CO₂ among gaseous mixtures. Sorbents can efficiently select CO₂ from the mixtures of gas streams or toward a specific gas relative to other gases present in the emission. The selectivity depends upon the efficiency of the sorbent attributed to its affinity toward a specific gas. Some sorbents contain a particular element(s) or functional group(s) naturally having a strong affinity to CO₂ and thus could greatly adsorb the CO₂ in a mixture of gases present in the emission stream.

For instance, functionalized MOFs, ionic liquids, and zeolites could exhibit such a selective characteristic if compared to alkaline-earth oxides and transition-metal oxides. In fact, transition-metal oxides have poor affinity toward CO₂ and, therefore poor selectivity. (ii) Cyclic regeneration of sorbents renders their applications more efficient and low-cost because of their prominent usability over many times, still keeping a high ability of adsorption–desorption. A sorbent should be regenerated for ultimate use without losing its ability for adsorption–desorption, meaning that it could offer a strong or permanent resistance to facile degradation and possible contamination for its lasting application.

Sorbent regeneration can be energy demanding, a process that needs elevated temperatures for desorption, which could cause potential structural degradation. In addition, since the adsorbent is extensively exposed to a mixture of uncertain gases named impurities, potential contamination could occur. If choosing the appropriate adsorbent for CO₂ abatement, adsorbent regeneration should be given particular consideration to ensure that the process has a low regeneration energy demand. Alkaline-earth oxides constitute a high-energy-demanding material for cyclic stability, causing particle sintering, and present handling concerns as a limitation to potential degradation. MOFs and ionic liquids are excellent materials against temperature sintering and degradation effects. (iii) The tunable property of solid sorbents is another desirable feature since sorbents can be constructed with functionalized materials for specific selectivity of CO₂ among other gases. Naturally, each type of sorbent has its own unique efficiency and potential limitations.

However, combining desirable characteristics of different elements or moieties could enhance the efficiency of sorbents. The advantage of using a solid sorbent can be attributed to the feasible tailoring of its structure with the possible incorporation of moieties or functional groups with a high affinity for CO₂ capture and release.

For example, MOFs have good properties such as macroporous structures that enable the adsorption of CO₂ into the pores; however, the efficiency has been identified as very low under normal operating conditions. To improve the performance and selectivity of MOFs toward CO₂ capture, researchers have incorporated amine functional groups into the porous structure to boost a higher efficiency relative to nontunable MOFs. Similar to MOF moieties, ionic liquids can also be tailored with porous and microporous structures, nanostructures, and functionalized structures with unprecedented simplicity in the formulation. Metal oxides have been reported for possible tailoring with double layers, which enhanced the gas uptake. Nanostructured metal oxides have been also synthesized; nevertheless, their handling prevents their scalability for trade-offs. (iv) Lastly, favorable operating conditions of solid sorbents can be traced to their applications at high or low temperatures and/or under high or low pressures. It could be noted that sorbents operate under temperature swing and pressure swing or through a combination of both. Adsorption can occur at lower temperatures or desorption at some higher temperatures. However, different sorbents can bear one/some or all of the mentioned desired features, and therefore, when choosing a solid sorbent, a close consideration of structural material and operating conditions could be of essential importance.

Sorbents could exhibit several benefits in the application of CO₂ capture and conversion because of an existing simpler tailoring and functionalization of sorbents’ structures with moieties that could have a high CO₂ affinity, sorption capacity, stability, and/or a CO₂ catalytic conversion. A typical example is a successful synthesis of dual-function materials (DFMs) based on transition metals such as nickel and ruthenium, in which the latter played a catalytic conversion of adsorbed CO₂ into useful products (Figure ). CaO-Ni DFM was reported as an efficient adsorbent capable of adsorbing CO₂ by the CaO adsorbent to produce CaCO₃ which at elevated temperature (800 °C) decomposes and releases CO₂ on the adsorbent interface to react with methane from dry reforming, therefore allowing syngas production. Indeed, Ni-based DFMs could be improved by incorporating other species such as cerium (Ce) and platinum (Pt), resulting in doped DFMs that can operate with a higher efficiency and lower energy. Such incorporated DFMs could be formulated by loading the Ni-based DFM with a trace amount of the corresponding precious metals known for their dissociation ability toward H₂, thereby lowering the reduction temperature. Note that some precious metals have strong activity and selectivity in the methanation of CO₂, and therefore, they can be used individually as metal-based DFM or can be modified/incorporated with other catalytic species in their formulations. Table summarizes the common types of sorbents used in CO₂ capture and their degree of preparation toward desirable features.

3.

Illustration of CO₂ capture and conversion toward methanation by DFMs.

1. Common Solid Sorbents Employed in Greenhouse Gases Separation.

	desirable feature
sorbent category	tunable	selectivity toward gas	cyclic stability	temperature condition (°C)	reference
alkaline-earth oxides	difficult	CO2, NO x	poor	>200
MOFs/ILs	easier	CO2, NO x , SO x , H2S	high	<200
zeolites	easier	CO2, NO x , SO x, H2S	poor	<200
transition-metal oxide	easier	H2S	poor	>200
Ni-based DFM	easier	flue gas: CO2, O2, N2, H2O	high	>700
Ru-based DFM	easier	flue gas: CO2, O2, N2, H2O	high	>300
Ca/Cu composite	easier	CO2	poor	>300

Metal–Organic Frameworks (MOFs)

MOFs are constructed based on structural building units made of metal clusters and organic linkers resulting in robust porous structures, promising for potential applications in the adsorption process as illustrated in Figure . Clearly, by a simple combination of metals and ligands, it is possible to design and synthesize limitless number of MOFs, therefore broadening the production and availability of MOF’s materials for commercialization. The well-known advantages of MOFs can be traced to (i) an easier structural formulation or modification where the metal containing nodes can be formed by a specific metal cluster that can enhance the adsorption of the targeted gas; (ii) the creation of permanent porosity that can boost the adsorption by a high permeability of CO₂ into the porous structures; (iii) tunability of MOF’s structures to obtain a desirable characteristic for specific applications; (iv) a higher surface area, and (v) MOFs can form composites or be mixed with other structures to enhance the performance of the combined newly structure. In this regard, MOFs are being extensively investigated for CO₂ capture.

4.

Illustration of the MOFs construction model.

Despite many advantages, there are limitations associated with the applications of MOFs. For example, facile degradation of MOFs occurs when exposed to water vapor or an acidic environment conditioned by a mixture of gases. Consequently, MOFs are less stable against water and could have poor performance in the separation of CO₂ in a mixture of flue gas that initially contains a high moisture content. Additionally, the presence of some impurity species can affect the low selectivity and adsorption of CO₂ because of potential interaction and competition of species to coordinate with the frameworks; therefore, water present in flue gas can be coordinated to frameworks by forming strong interactions that could be of a total occupancy of sites for CO₂ adsorption; therefore, it could decrease the adsorption of CO₂. Not only water, however, some other trace contaminants in flue gas can have such outcompete CO₂ effect on the framework sites.

Electrochemical CO₂ Capture Approach

Electrochemically mediated CO₂ capture is an emerging new class of carbon-abatement strategies. Unlike traditional systems that operate under temperature and pressure swings, the electrochemical method is a current–potential-dependent product that may offer solutions to overcome the existing barriers in CO₂ capture and reduction by conventional environments. Indeed, this approach uses a wide range of substances with the ability to capture CO₂ through chemical affinity mediated by the moieties bearing specific functional groups and finally can release the CO₂ under the application of an external current (Figure ).

5.

Representation of an electrochemically mediated CO₂ capture, release, and storage.

The advantages of electrochemically mediated CO₂ capture are many and could suppress the downsides of the current abatement strategies. The well-known benefits of the electrochemical technique in CO₂ capture are that the applied current potentials can be controlled or adjusted to target a specific reaction which can result in a CO₂ concentration, separation (release), or CO₂ conversion with a high possibility of minimizing undesired side reactions. The energy required for sorbent regeneration is lowered compared with conventional techniques. The high stability of sorbents and long cyclability ensure a long-term use of sorbents. Finally, the electrochemical approach is a green technology that is nontoxic and independent of fuels or steam.

The availability and low cost of redox-active materials could offer a better choice of selection of materials with a high selectivity and affinity for CO₂. For example, transition-metal complexes through various oxidation states could modulate the competition for CO₂ capture or release by turning on and off the oxidation state.

Despite the accounted positive characteristics of electrochemically mediated CO₂, however, the final output of desorbed CO₂ can be estimated to be low and yet without an ultimate application. Nevertheless, electrochemical CO₂ reduction in the formulation of formate was reported, unveiling a potential large-scale production of many other useful products from formate as a starting material.

Quantitative comparison (Table ) shows that no single CO₂ utilization technology dominates all performance metrics. Electrochemical methods currently offer the highest efficiency and product selectivity. Nevertheless, their high electricity demand (2–8 kWh/kg of CO₂) and reliance on expensive catalysts limit economic viability, especially where renewable energy is not consistently available. MOFs exhibit outstanding CO adsorption capacities and highly tunable catalytic properties, enabling elevated selectivity (up to 80–90%). However, their large-scale application remains constrained by limited long-term structural stability, susceptibility to moisture, and challenges associated with cost-effective and scalable syntheses.

2. Quantitative Comparison of Recent Development in Carbon Capture, Utilization, and Storage Technologies.

technology	conversion efficiency (%)	energy requirement	products	technology readiness	critical quantitative interpretation
MOFs	80–95	low-moderate	CO, CH4	pilot-emerging	high reported conversion efficiency, technology mature, and scale-up remain important limitations
electrochemical CO2 reduction	40–70	2–8 kWh per kg CO2	CO, ethylene, ethanol	pilot-early commercial	high conversion efficiency, but electricity demand can strongly influence environmental and economic performance
photocatalytic conversion −	0.2–1	solar-driven	CH4, CO, methanol, HCOOH	lab-pilot	lower conversion efficiency, but potentially favorable where solar energy is available and process energy is low-carbon
biobased reduction	1–5	low	biomass, biofuels	commercial-pilot	lower conversion efficiency but potentially lower transformation-energy requirements and compatibility with biological carbon-circularity pathways
artificial photosynthesis	1–10	solar-driven	liquid fuels, methanol	early stage	solar-driven conversion provides sustainability potential, but efficiency and technology maturity remain major constraints

Photocatalytic and artificial photosynthesis approaches are currently constrained by relatively low conversion efficiencies (0.2–10% in the pathways summarized in Table ), although they offer significant promise for long-term sustainability because of their reliance on solar energy. Electrochemical CO₂ reduction exhibits substantially higher reported conversion efficiency (40–70%) but requires approximately 2–8 kW per kg CO₂, illustrating the trade-off between conversion performance and energy demand. MOF-based systems also show comparatively high conversion efficiencies (80–90%) with low-to-moderate energy requirements, whereas biobased CO₂ reduction systems demonstrate lower conversion efficiencies (1–5%) but comparatively low energy demand. These differences demonstrate that conversion efficiency alone cannot identify the most advantageous CO₂ utilization pathway; energy intensity, product type, and technology readiness must also be considered.

Therefore, future advancements are likely to rely on the development of hybrid systems (e.g., MOF-assisted electrochemical or photoelectrochemical processes) that synergistically integrate high conversion efficiency, reduced energy input, product selectivity, and improved scalability. Importantly, these technical indicators provide the quantitative foundation for the carbon value retention (CVR) framework developed further because a pathway that converts a large fraction of CO₂ but requires high energy input may retain less net carbon value than a pathway with lower conversion efficiency but lower transformation burden and longer carbon retention.

Carbon Destiny Criteria for Evaluating CO₂ Sequestration and Utilization Technologies

Despite remarkable advances in CCSU technologies, the selection of appropriate carbon management strategies remains largely technology driven. Existing frameworks typically compare capture processes based on technical indicators such as capture efficiency, energy consumption, operating cost, and the technology readiness level. While these criteria are indispensable for engineering optimization, they provide only a partial assessment of the overall contribution of CCSU technologies to climate change mitigation. Specifically, they seldom address the ultimate fate of captured carbon after separation from the emission source or its long-term contribution to industrial sustainability. Consequently, technologies exhibiting similar capture efficiencies may differ in their ability to achieve permanent carbon removal, create economic value, or support the transition toward a circular carbon economy.

Inspired by recent advances in carbon circularity, , carbon permanence assessment, , and life-cycle-based evaluation , of CCSU pathways, this review proposes a carbon destiny framework (CDF) as a complementary perspective for evaluating CO₂ sequestration and utilization pathways. The framework evaluates technologies according to the ultimate destiny of the captured carbon and the associated long-term environmental and socio-economic outcomes. The sustainability of CCSU technology depends not only on how effectively CO₂ is captured but also on whether the captured carbon is permanently isolated from the atmosphere, repeatedly circulated within industrial systems, converted into durable products, or rapidly re-emitted after use.

The CDF is structured around five complementary decision criteria. The first criterion, carbon permanence, evaluates the expected duration for which the captured carbon remains isolated from the atmosphere. The second, carbon value creation, assesses the extent to which captured CO₂ is transformed into economically valuable products capable of offsetting the capture and processing costs. The third criterion, carbon circularity, measures the potential for captured carbon to be repeatedly reused within industrial value chains, thereby reducing the dependence on virgin fossil carbon resources. The fourth criterion, carbon transformation complexity, considers the technological complexity, energy demand, and process integration required to convert captured CO₂ to useful products. Finally, societal and environmental impact evaluates the broader contribution of each pathway to climate change mitigation, resource efficiency, industrial decarbonization, and long-term sustainable development.

Unlike conventional CCSU evaluation frameworks that emphasize engineering performance, the proposed carbon destiny criteria (Table ) provide a complementary perspective by evaluating technologies according to the long-term fate, value creation, circularity, sustainability, and transformation complexity of the captured carbon. This Perspective could enable policymakers, researchers, and industrial stakeholders to compare CCSU technologies not only according to engineering performance but also according to their capacity to generate durable climate benefits and sustainable industrial value. Consequently, the framework provides a strategic basis for prioritizing future investments and research toward carbon management pathways that maximize both the environmental impact and economic resilience.

3. Proposed Carbon Destiny Criteria (CDC) for Evaluating CO₂ Sequestration and Utilization Technologies.

carbon destiny criterion	key evaluation question	decision-making value
carbon permanence potential	how long will the captured carbon remain outside the atmosphere?	evaluates long-term climate benefits beyond capture efficiency
carbon value multiplication	how much economic value can be generated from captured CO2?	links carbon management with industrial value creation
carbon circularity potential	can the captured carbon be continuously reused without relying on fossil carbon?	assesses contribution to a circular carbon economy
carbon legacy potential	what long-term environmental legacy does this carbon pathway create?	considers intergenerational sustainability and permanent carbon removal
carbon transformation complexity	how complex is the conversion of captured CO2 into a stable or valuable product?	evaluates process simplicity, scalability, and energy demand

Current Applications of Sequestrated the CO₂

The ideal application of sequestrated CO₂ could only be limited to its storage in solid forms for a limited number of applications in a real modern society. Though the solid forms are known for their stability in storing the captured CO₂ over long period, however, there are not well-known best practices for the use of these solid material forms in useful products to minimize and compensate for the capturing cost and environmental sustainability. Given the current infrastructure development across the globe that uses an unlimited number of concrete materials, storing materials in carbonate forms could find a place in such applications as sustainable materials, but there are still not enough applications to convert the sequestrated CO₂ into concrete materials.

Other studies suggested a prominent utilization of the captured CO₂ through mineralization of industrial waste or activated minerals that could form stable carbonate materials by reaction with the so -captured CO₂. Though industrial waste is readily available and abundant, however, this approach cannot be reliable considering the uncertainty in the composition of industrial waste and long-term use of the same manufacturing process which can change all along with technological advancements in the process and product development.

A recent study has revealed a development of pilot large-scale absorption of CO₂ by using amine-based solutions filled in tanks capable of capturing CO₂ directly from the atmosphere. The absorbing tanks are equipped with pipes under which the supplied external energy source could release the absorbed CO₂ for subsequent underground storage in the form of carbamates, yet of no further applications for materials synthesis. This practice though could gradually reduce the amount of released CO₂ into the atmosphere over a long period; however, the approach does not provide a sustainable application of the sequestrated CO₂, thus imposing a limited storage capacity for the proposed technology.

Innovations and Large-Scale Industrial Applications

One of the most significant innovations in the advancement of CCU technologies is combining efficient CO₂ capture with catalytic, electrochemical, photochemical, and biological conversion processes. Recent developments in heterogeneous catalysts, metal–organic frameworks (MOFs), ionic liquids, membrane separation technologies, and high-performance electrochemical reactors have improved CO₂ adsorption capacities, conversion efficiencies, product selectivity, and energy utilization. These innovations are gradually overcoming traditional limitations associated with the high thermodynamic stability of CO₂, thereby expanding opportunities for its industrial transformation into commercially valuable products (Table ).

4. Current CO₂ Utilization Pathways and Their Carbon-Retention Characteristics.

application category	CO2 consumption (Mt/yr)	technology type	key products	carbon permanence	permanence score (P)	CVR implication
, enhanced oil recovery (EOR)	∼80	direct use (injection)	oil extraction	low (re-emitted later)	1	high utilization volume, limited long-term carbon retention
urea/fertilizer production	∼130	chemical conversion	urea	low-medium	2	very large utilization volume and established market, limited long-term carbon retention
synthetic fuels (e-fuels)	<10	thermo-/electrochemical	methanol	low (combustion releases CO2)	1	provides carbon recycling and fuel value, but carbon is rapidly returned to the atmosphere
chemicals & polymers	∼10–20	catalytic conversion	methanol, polymers, carbonates	medium	3	intermediate value potential, carbon lifetime depends on product structure and end-of-life treatment
, building materials (concrete)	∼5–10	mineralization	carbonated concrete	high (long-term storage)	4	strong retention potential and material value generation
− carbon materials	<1	advanced conversion	CNTs, graphene, nanomaterials	high	5	very high carbon value retention and high value products, limited market

^aPermanence score (P) is an ordinal screening scale ranging from 1 to 5, developed to comparatively assess the expected duration of carbon retention across different CO₂ utilization pathways. A score of 1 represents relatively short-term carbon retention, whereas a score of 5 represents the highest expected long-term retention potential. The scores do not represent measured carbon lifetimes or specific durations; they provide a comparative ranking based on the carbon fate and permanence descriptions reported in the manuscript.

Among large-scale industrial applications, the construction sector currently offers one of the most promising avenues for long-term carbon sequestration. Accelerated mineral carbonation technologies enable captured CO₂ to react with calcium- and magnesium-rich materials to produce stable carbonate minerals that can be incorporated into cement, concrete, aggregates, and prefabricated construction components. Beyond permanently immobilizing carbon, these technologies have demonstrated improvements in concrete strength, durability, and curing efficiency while reducing the carbon footprint of the construction industry. Considering the enormous global demand for concrete, the widespread implementation of carbonated construction materials could contribute substantially to long-term atmospheric CO₂ reduction.

The chemical industry has also emerged as an important consumer of captured CO₂ through the synthesis of methanol, urea, formic acid, cyclic carbonates, polycarbonates, and other specialty chemicals. Although some chemical products ultimately release CO₂ during their life cycle, advances in catalyst design and renewable hydrogen integration continue to improve both the carbon efficiency and process sustainability.

Another rapidly developing area involves the production of synthetic fuels, where renewable electricity is combined with captured CO₂ to generate methanol, methane, aviation fuels, and other liquid hydrocarbons. These technologies provide an attractive option for decarbonizing sectors that are difficult to electrify.

Emerging technologies have further demonstrated the feasibility of converting captured CO₂ into advanced carbon materials, including carbon nanotubes, graphene, carbon nanofibers, and other engineered carbon structures. These high-value materials possess exceptional electrical, mechanical, and thermal properties, making them suitable for applications in energy storage, electronics, composites, sensors, and environmental remediation. Although large-scale commercialization remains under development, these technologies represent one of the most promising pathways for simultaneously achieving long-term carbon retention and high economic-value generation.

Despite these remarkable technological advances, significant barriers continue to limit the widespread industrial deployment. High capital investment, energy-intensive capture and conversion processes, limited renewable energy availability, infrastructure requirements for CO₂ transportation and storage, regulatory uncertainties, and inconsistent carbon pricing mechanisms remain as major obstacles to commercialization. Furthermore, the long-term environmental performance of many emerging technologies requires comprehensive life-cycle assessment to ensure that net greenhouse gas emissions are genuinely reduced rather than shifted across different stages of production.

Future innovations should therefore focus on digital process optimization, artificial intelligence-assisted catalyst design, and industrial symbiosis expected to accelerate the commercialization of next-generation carbon management technologies. Such integrated approaches have the potential not only to enhance the economic viability of CO₂ sequestration but also to establish captured carbon as a renewable industrial resource that contributes simultaneously to climate change mitigation, sustainable manufacturing, and the realization of global net-zero emission targets.

The quantitative data in Table indicate that current CO₂ utilization is dominated by high-volume pathways with limited carbon permanence. Urea production (∼130 Mt yr^–1) and enhanced oil recovery (EOR) (∼80 Mt yr^–1) together account for approximately 210 Mt yr^–1 or about 91% of the reported ∼230 Mt yr^–1 total utilization. This is important because utilization volume does not necessarily translate into long-term carbon retention. In contrast, building materials/mineralization (∼5–10 Mt yr^–1) and advanced materials (<1 Mt yr^–1) represent much smaller current utilization volumes but offer substantially greater potential for durable carbon retention. The comparison therefore reveals a fundamental distinction between CO₂ utilization scale and CVR, providing the quantitative basis for the CVR framework developed below.

Reframing CO₂ Sequestration and Utilization within a CVR Perspective

A key observation emerging from this Review is that current CO₂ sequestration technologies are generally evaluated using metrics such as capture efficiency, storage capacity, energy demand, and cost. While these indicators are important, they do not adequately reflect the long-term climate benefits of a technology or its contribution to sustainable industry development. Therefore, this review proposes a CVR framework that evaluates sequestration pathways according to two interconnected criteria: (i) the duration for which carbon remains isolated from the atmosphere and (ii) the economic value generated from the sequestrated carbon.

Under this framework, CO₂ utilization pathways can be classified into four categories (Table ): Temporary carbon use, transitional carbon storage, permanent carbon locking, and regenerative carbon assets. Temporary carbon use includes applications such as synthetic fuels, in which carbon is rapidly re-emitted after utilization. Transitional carbon storage encompasses products, such as polymers and chemical intermediates, that retain carbon for moderate periods. Permanent carbon locking includes mineral carbonation and carbonated construction materials that immobilize carbon for decades to centuries. Regenerative carbon assets represent the highest-value category, where captured CO₂ is transformed into advanced materials such as carbon-based products capable of long-term carbon retention while generating a substantial economic value. These carbon products may include carbon nanotubes, graphene, carbon fibers, and other engineered carbon structures. This multidimensional perspective provides a more comprehensive understanding of the factors governing the large-scale deployment of the sequestration technologies.

5. Quantitative Carbon Value Retention (CVR) Assessment of Representative CO₂ Utilization Pathways.

category	CO2 utilization pathway	CO2 consumption (Mt yr–1)	carbon retention	permanence score (P)	economic value score (V)	indicative CVR score (%)
temporary carbon use	enhance oil recovery	∼80	low, carbon is largely re-emitted	1	4	50
	synthetic fuels/e-fuels	<10		1
transitional carbon storage	urea/fertilizer production	∼130	low-medium	2	4	60
	chemicals and polymers	∼10–20		3		70
permanent carbon locking	building materials/mineralization	∼5–10	high, decades-centuries	4	3	70
regenerative carbon assets	advanced carbon materials	<1	high, long-term potential	5	5	100

The indicative CVR score is calculated using the two principles dimensions of the proposed framework: carbon permanence (P) and economic value (V). Each dimension is scored on a 1–5 ordinal screening scale, where higher scores represent longer carbon retention and greater economic value, respectively. For screening purpose, the dimensions are equally weighted:

$$\mathrm{C}\mathrm{V}\mathrm{R}=100\times [0.5(P/5)+0.5(V/5)]$$

Note that the resulting score is intended as a comparative screening index rather than a validated life cycle, techno-economic, or market-value metric. The weighting can be modified according to the assessment objectives.

A major synthesis emerging from this review is therefore the recognition that future carbon-neutral economies will require a shift from the traditional “capture and store” paradigm toward the “capture, utilize, and circulate” model. The quantitative comparison indicates that this transition should not be based solely on maximizing CO₂ consumed. Instead, future deployment should prioritize pathways that combine high carbon permanence, meaningful product value, acceptable energy requirement, and sufficient technology maturity. Mineralized construction materials and advanced carbon materials are particularly promising from a CVR perspective because they can combine relatively long carbon retention with industrial value, whereas EOR and synthetic fuels provide important short-term utilization markets but have limited long-term carbon retention. The CVR framework offers a complementary basis for prioritizing research and investment toward pathways that minimize the long-term environmental and economic value retained from captured CO₂. Therefore, such a perspective provides a new basis for comparing sequestration technologies and identifying pathways most capable of contributing to a sustainable net-zero carbon economy.

Limitations and Future Development of the CVR Framework

The proposed CVR framework should be interpreted as a conceptual and semiquantitative decision framework rather than as a fully validated techno-economic or life-cycle assessment. Its principal contribution is to shift the evaluation of CO₂ management pathways beyond the conventional metrics of capture efficiency and utilization volume by explicitly considering what happens to carbon after capture and conversion, namely, how long it remains retained and what economic value is generated during that period. However, several limitations must be acknowledged before the framework can be applied as a predictive or prescriptive decision making tool.

First, the current scoring system relies on ordinal classifications that may oversimplify complex and pathway-specific factors. Carbon permanence depends not only on the product lifetime but also on degradation, end-of-life management, and the potential for CO₂ release. Similarly, the economic value can vary with market conditions, production scale, geographical context, and energy requirements. Consequently, a high-value product does not necessarily translate into superior carbon management performance if its production requires considerable energy or generates significant upstream emissions.

Second, the present framework does not yet explicitly quantify the trade-offs between carbon retention and the environmental burdens associated with the conversion of CO₂. This is particularly important because some pathways may demonstrate high conversion efficiency or produce valuable products while simultaneously requiring considerable amounts of electricity, hydrogen, heat, catalysts, or other material inputs. Under such conditions, the apparent value of retaining carbon could be offset by indirect greenhouse gas emissions or resource consumption. Future development of the CVR framework should therefore incorporate life-cycle greenhouse gas emissions, carbon intensity of energy inputs, material consumption, and process efficiency to distinguish gross carbon retention from net climate benefit.

Third, the equal weighting assigned to carbon permanence and economic value in the present scoring approach is intentionally illustrative, rather than normative. The relative importance of these dimensions depends on the purpose of the assessment. A climate mitigation strategy, for example, may prioritize long-term carbon permanence, whereas an industrial deployment strategy may place greater emphasis on economic value, scalability, or technological readiness. Future versions of the framework should therefore employ context-specific weighing schemes, supported by multicriteria decision analysis and sensitivity analysis, to determine how changes in weighting influence the ranking of competing CO₂ management pathways.

Accordingly, the next stage of development should move the CVR framework from semiquantitative classification toward empirical validation. This could be achieved by integrating experimentally measured carbon incorporation, product-specific retention times, probability of carbon release, life-cycle greenhouse gas emissions, energy and material requirements, lifetime adjusted processing costs, market value, and realistic deployment capacity. These variables could then be incorporated into a multicriteria or weighted decision model and tested against representative CO₂ management pathways. Sensitivity and uncertainty analyses would be particularly important to determine whether pathway rankings remain robust under different energy scenarios, product lifetimes, market conditions, and policy assumptions.

Ultimately, the value of the CVR framework lies not in replacing established life-cycle assessment, techno-economic analysis, or conventional CCUS performance metrics but in providing a complementary perspective that connects carbon fate with value creation. A mature version of the framework could therefore serve as an integrative layer linking the capture performance, conversion efficiency, energy demand, carbon permanence, economic value, and deployment potential. Such integration would provide a more rigorous basis for identifying CO₂ management pathways that are not only technically feasible and economically attractive but also capable of delivering meaningful and durable climate benefits.

Conclusions and Future Opportunities

Conclusions

This review examines the current challenges, advances, and future opportunities associated with carbon capture, utilization, and storage (CCUS), with particular attention to the transition from conventional CO₂ management toward value-oriented carbon utilization. Although a wide range of materials and technologies have been developed for CO₂ capture and conversion, the continued dependence on fossil fuels remains a major driver of increasing atmospheric CO₂ concentrations. The scale of anthropogenic emissions continues to exceed the capacity of existing capture and utilization technologies, highlighting the need for more efficient, scalable, and sustainable carbon management strategies.

CO₂ utilization presents an important opportunity to complement sequestration by converting captured carbon into useful products, including syngas, acetic acid, formate, polymers, ethanol, and advanced carbon materials, such as carbon nanotubes. However, this Review demonstrates that the quantity of CO₂ utilized alone is not a sufficient indicator of environmental benefit. The long-term contribution of a utilization pathway depends on several interconnected factors, including the carbon retention time, conversion efficiency, energy requirements, product value, technology maturity, and the potential for large-scale deployment.

Although geological storage remains an important pathway for durable CO₂ sequestration, its primary limitation from a circular economy perspective is that captured carbon is generally removed from industrial value chains rather than converted into useful products. Conversely, CO₂ utilization can generate economic value and contribute to carbon circularity; however, its climate benefits depend strongly on the fate of the carbon after conversion. Pathways that produce short-lived products, such as fuels, may recycle carbon temporarily but eventually return it to the atmosphere, whereas mineralized materials and certain advanced carbon products may provide longer-term carbon retention.

This review proposed a CVR framework that provides a complementary perspective for evaluating CO₂ utilization pathways beyond conventional measures of capture efficiency or utilization volume. The framework emphasizes two fundamental dimensions: the permanence of retained carbon and the economic value generated from its utilization. The quantitative comparison presented in this Review highlights an important distinction between high-volume CO₂ utilization and high CVR. Therefore, future CO₂ management strategies should not focus on maximizing the amount of CO₂ consumed but should seek to optimize the balance among carbon permanence, product value, energy demand, conversion performance, and technological scalability.

Future Opportunities in CCU

The future of the CCU process can be considered along two closely interconnected directions: the development of efficient and sustainable systems for CO₂ capture and the transformation of captured CO₂ to products that provide meaningful environmental and economic value. Progress in capture material remains important, particularly through the development of new classes of sorbents and the improvement of existing materials to enhance CO₂ uptake, selectivity, regeneration, and long-term stability. However, improvements in the capture capacity alone should not be considered sufficient indicators of technological progress. The energy required for sorbent regeneration, the carbon intensity of the energy source, material durability, and the environmental impacts associated with material production and disposal must also be considered. Future capture technologies should therefore be evaluated on the basis of their overall system performance rather than on the basis of adsorption capacity alone.

The development of sustainable and low-cost sorbents presents a promising direction. For example, cellulose-based and other biomass-derived materials may offer opportunities for producing capture materials from renewable and widely available resources while simultaneously creating additional value from agricultural and industrial residues. Such approaches could contribute to both carbon management and circular economy objectives. Nevertheless, the sustainability of bioderived sorbents should be assessed over their full life cycle, including material processing, regeneration requirements, durability, and end-of-life management. Future research should therefore focus not only on identifying materials with high CO₂ uptake but also on demonstrating whether these materials can maintain their performance during repeated capture-regeneration cycles under realistic operating conditions.

Attributed to their high CO₂ affinity at low pressure, tailored solid sorbents could be used for capturing dilute CO₂ streams, including atmospheric CO₂ and emissions from dispersed sources. Materials with high affinity for CO₂ at low partial pressures could contribute to DAC and other distributed carbon removal applications. However, practical implementation of such approaches remains challenging. In particular, systems deployed over large or open areas would require efficient strategies for material recovery, regeneration, CO₂ collection, and subsequent transportation or utilization. The future development of distributed capture systems must therefore address the complete carbon management chain rather than focusing exclusively on the adsorption process. Their practical value will depend on whether captured CO₂ can be efficiently concentrated, collected, and directed toward permanent storage or productive utilization.

Another important opportunity lies in the formulation of the CO₂-derived construction materials. Mineralization and carbonation processes can incorporate captured CO₂ into concrete, aggregates, and other construction products, potentially combining carbon management with infrastructure development. From the perspective of the proposed CVR framework, such pathways are particularly attractive because they may provide both relatively long carbon retention and useful material value. Carbon incorporated into stable mineral phases can remain stored for extended periods, while the resulting products can serve as practical functions within the built environment. However, the overall climate benefit will depend on the energy and material requirements of the carbonation process, the extent of CO₂ incorporation, the durability of the final products, and the emissions associated with cement and construction material production. Noting that the captured CO₂ could have an application if more efforts are put into the utilization of the sequestrated CO₂ in such an emerging field of infrastructure development, future research should therefore focus on maximizing net carbon retention rather than simply increasing the quantity of CO₂ incorporated into construction materials.

In the energy field, as an emerging technology for the production of carbon feedstock-based fuel, sequestrated CO₂ could have a significant application in converting the captured CO₂ into liquid fuel as the technology development continues to its advanced stage. From a recent promising technology that has not yet proven its scalability potential, it was revealed that CO₂ could serve as a raw material in the production of syngas, ethanol, and other synthetic fuels and chemicals. These pathways could support the gradual replacement of fossil-derived carbon feedstock and contribute to carbon circularity. However, their climate benefits should be evaluated critically. For fuel applications, the carbon is generally released back into the atmosphere when the fuel is used, meaning that such pathways provide carbon recycling rather than permanent carbon storage. Their contribution to climate mitigation therefore depends strongly on the source of energy and hydrogen used during conversion and on whether fossil carbon is genuinely displaced. Within the CVR perspective, fuel production may provide economic and strategic value but generally offers lower carbon permanence than mineralized products or durable carbon materials. Future research should therefore distinguish clearly between temporary carbon circulation and long-term carbon retention.

To restore the amount of CO₂ in the air to acceptable levels for human survival, a cheap and efficient technology to sequester CO₂ needs to be thought of. Though there exist measures from some power plants to cut off carbon dioxide from their exhaust, the technique does not apply to other CO₂ sourcing such as from airplanes, automobiles, home heating systems, or forest/bush burning. Renewably sourced electricity technology could be a potential solution if it is well designed and developed. In fact, some molecules or electrolytes upon exposure to electrical potentials are able to take extra electrons, then become negatively charged, and so could have a high chemical affinity to CO₂ in their vicinity (ambient or exhaust air). Inversely, when these extra electrons are removed from the molecules or electrolytes, the CO₂ affinity of these molecules instantly disappears and releases captured CO₂ for subsequent storage or transformation. Such a system could enable compact, flexible, and modular carbon-capture devices suitable for distributed emissions sources. Nevertheless, several challenges must be addressed before widespread implementation becomes possible, including energy efficiency, electrode durability, material stability, device size, CO₂ throughput, and the manufacturing cost. Advances in nanostructured electrodes, high-capacity electrochemical materials, and modular reactor designs may contribute to overcoming these limitations. The availability of low-carbon electricity will remain particularly important because the environmental advantage of electricity-driven CCU systems depends strongly on the carbon intensity of the electricity supply. Definitely, the future of such a technology is in the hands of researchers and industry counterparts. However, without cheap renewable energy, many CCU pathways could remain economically uncompetitive compared with conventional fossil-based processes.

From a broader perspective, the future of CCU is unlikely to depend solely on incremental improvements in individual capture or conversion technologies. The central challenge is achieving system-level integration under realistic industrial conditions. A technically successful laboratory process may not necessarily deliver meaningful climate benefits when energy demand, material requirements, infrastructure, transportation, product lifetime, market demand, and end-of-life management are considered. Future CCU developments should therefore move toward integrated assessment approaches that combine technical performance with life cycle environmental impacts, economic feasibility, carbon permanence, and deployment potential.

In this context, the CVR framework provides an additional perspective for guiding future CCU developments. Rather than evaluating technologies solely according to the amount of CO₂ captured or utilized, future strategies should consider the fate of carbon after utilization and the value generated throughout its lifetime. Pathways that combine durable carbon retention with meaningful economic value may offer greater long-term benefits than high-volume applications, in which carbon is rapidly returned to the atmosphere. At the same time, high-CVR pathways must demonstrate sufficient scalability and acceptable energy requirements to make a meaningful contribution to climate mitigation. Future research should therefore focus on identifying the optimal balance among the CO₂ capture efficiency, conversion performance, energy demand, carbon permanence, economic value, and deployment scale.

Simply, the transition from conventional carbon storage to integrated carbon capture, utilization, and circularity systems represents an important opportunity for future carbon management. The most promising pathways will not necessarily be those that consume the largest quantity of CO₂ but those capable of delivering measurable and durable climate benefits while generating sufficient value to support large-scale deployment. In this regard, the future of CCU should increasingly be directed toward technologies and products that maximize net CVR by combining efficient capture, low-carbon conversion, durable carbon storage, meaningful economic value, and realistic scalability while contributing to global net-zero-emission objectives.

B.R. conceived and design this work. All authors contributed to the critical review, editing, and revision of the manuscript. B.R., J.N.H., F.N.N., and P.C.G. have given approval to the final version of the manuscript.

The authors declare no competing financial interest.