Carbon Capture Science & Technology最新文献

The utilization of dual functional materials (DFMs) in integrated CO₂ capture and utilization (ICCU) has been attracted increasingly attention, with the conversion of CO₂ to CH₄ through the Sabatier reaction offering significant thermodynamic benefits. Ni, recognized for its catalytic efficiency among transition metals due to its cost-effectiveness and natural abundance while Ni-based DFMs have been favored to promote the conversion of CO₂ to value-added chemicals. In the past decades, significant efforts have been dedicated to developing more efficient Ni-based catalysts to enhance CO₂ conversion and CH₄ selectivity. This study researched the thermodynamic and kinetic aspects of ICCU and summarized the recent industrial process at first. Then, an overview of the advancements in Ni-based DFMs, including synthesis methods, support materials and promoters were provided. Next, the mechanisms of CO₂ methanation were also briefly addressed to provide a comprehensive understanding of the process. Finally, the future prospects were guided the development and application scenarios of Ni-based DFMs in the ICCU.

Post-combustion carbon dioxide (CO₂) capture/separation is considered one of the main ways to minimize the impact of global warming caused by this greenhouse gas. This work used eight mono- and dicarboxylate-based ionic liquids (ILs) to impregnate metal-organic framework (MOF) ZIF-8. This anionic effect was studied for these mostly unreported IL@MOF composites to determine its impact on gas sorption and selectivity performance. Characterization results confirmed IL impregnation into the structure of ZIF-8, along with the conservation of microporosity and crystallinity in composites. Sorption-desorption equilibrium measurements were performed, and CO₂ and nitrogen (N₂) isotherms were obtained at 303 K for ZIF-8 and IL@ZIF-8 composites. At 0.15 bar, the dicarboxylate-based composite [C₂MIM]₂[Glu]@ZIF-8 showed the highest CO₂ gas sorption, showing 50 % more sorption capacity than the best monocarboxylate-base composites at this pressure. Dicarboxylate-based composites also showed remarkable N₂ sorption in the low-pressure range. The ideal CO₂/N₂ selectivity for a typical post-combustion composition was calculated, and a trend regarding the anionic carbon chain size was observed. The composite [C₂MIM][Cap]@ZIF-8 showed nearly five times more selectivity than the pristine ZIF-8 at 1 bar of total pressure. Dicarboxylate-based composites, given their low-pressure high N₂ sorption capacity, were not as selective as their respective monocarboxylate-based IL@ZIF-8 materials with the same carbon chain size.

Composite membranes incorporating ionic liquids (ILs) within MXene demonstrate promising potential for CO₂ separation. However, studies on the separation of CO₂/CH₄ using MXene-confined ILs membranes are limited, especially in terms of understanding the mechanisms at the molecular level. In this work, the system of CO₂/CH₄ in MXene-confined ILs membranes was studied by molecular dynamic simulations. The number density results reveal that MXene stratifies the ILs between the layers, with higher concentrations of ILs near MXene and lower concentrations in the middle layer. Notably, MXene has a greater impact on cations distribution compared to anions. As the layer spacing of MXene expands from 1.5 to 3 nm, the interaction between MXene and IL weakens, while that between the cations and anions strengthens. The confined ILs enhance gas solubility capability but impede gas diffusion. CO₂ is distributed closer to anions, while CH₄ tends to be closer to cations, with the distance between CH₄ and cations decreasing as the layer spacing increases. Additionally, with the increase of layer distance, the proportion of confined ILs gradually decreases, and the gas diffusion coefficient gradually increases. Furthermore, compared to 1-Ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF₄]) and 1-Ethyl-3-methylimidazolium hexafluorophosphate ([EMIM][PF₆]), MXene-confined 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TF₂N]) is identified as the most effective for CO₂/CH₄ separation, owing to its superior CO₂ solubility and highest diffusion selectivity.

Carbon dioxide (CO₂) is a ubiquitous molecule that is essential for the existence of life on Earth. However, the ever-increasing anthropogenic CO₂ emissions in the environment have resulted in global warming-via-climate change. CO₂ is an inexpensive substrate that can be utilized to produce fuels and value-added chemicals through numerous chemical and biological processes to boost the circular economy with a negative carbon cycle in the future. Conventional technologies practiced capturing CO₂ suffer from several limitations, such as high capital costs, high energy input, complicated designs, CO₂ leakage, and kinetic limitations in various steps. To offset these limitations and negative impacts, this study assessed the emerging CO₂ capture and sequestration (CCS) technologies in value-added products that can boost the nation's economy and lower energy consumption while preserving global environmental quality. Various emerging CCS technologies, such as heterogeneous catalytic conversion, plasma technology, photocatalytic conversion, and other technologies (electrochemical or electrocatalysis, photoelectrochemical, thermo-catalysis, and biochemical and radiolysis), were discussed for efficient utilization and transformation of CO₂. In addition, it also explored how the various transformation technologies affected the characteristics, economic value, and quality of value-added chemicals/fuels. This review also covered environmental and economic implications from scientific perspectives, and lastly, the future outlook and associated challenges were discussed.

Plastic consumption has surged due to population growth and shifts in consumer behavior. Upcycling aims to address plastic waste by finding innovative reuse strategies. By integrating waste plastic into new products and materials, upcycling supports a more sustainable and environmentally friendly economic model. This reduces the overall environmental footprint, including CO₂ emissions, associated with plastic consumption. Moreover, converting plastic waste into carbon nanotubes, can effectively sequester carbon. This means that carbon is captured and stored in a stable form, preventing its release into the atmosphere as CO₂. This contributes directly to reducing net emissions. Recent interest in upcycling strategies includes producing target-oriented catalysts to reform plastic waste into carbon nanotubes embedded spent catalysts, offering potential for various applications. However, research in this area is scattered and lacks comprehensive conclusions. This review critically examines the use of spent catalysts from plastic waste pyrolysis and identifies their suitability for practical applications. It suggests focusing on the catalytic pyrolysis of plastic waste for target-oriented catalysts, as they offer good hydrogen yield and post-pyrolysis use in targeted applications. The unique structure of these catalysts enhances performance compared to commercial alternatives, but post-treatment is crucial to remove impurities for optimal performance. The upcycling of plastic waste into CNTs-metal composites substantially contributes to Sustainable Development Goals 7, 9, 12 and 13, by taking action to combat climate change and by guaranteeing access to affordable, clean, and sustainable energy. This review aims to be helpful for researchers who are currently new to the topic and want to continue research in this domain.

Capturing CO₂ and converting it into valuable chemicals has attracted considerable attention in recent years. Herein, a kind of ether chain-modified alkanolguanidines (ECMAs) was designed and synthesized as a dual functional reagent for carbon dioxide capture and conversion. Due to the presence of basic sites and CO₂-philic ether chains, these ECMAs demonstrated almost equimolar CO₂ capture at room temperature and atmospheric pressure through the synergy of physical and chemical absorption. Even for diluted CO₂ (15 % CO₂), 0.7 mol CO₂ per mole capture reagent can still be achieved, showing their potential application in post-combustion capture. The synthesized ECMAs can also serve as catalyst in the cycloaddition reaction of CO₂ with various epoxides, affording 75–99 % yield of corresponding cyclic carbonates under 3 MPa CO₂ with tetrabutylammonium iodide (TBAI) as co-catalyst. Moreover, these ECMAs can be applied to the integrated CO₂ capture and conversion, in which the ECMAs can react with CO₂, forming the alkyl carbonate zwitterion as active CO₂ species in the capture step. And in the subsequent cycloaddition reaction with propylene oxide, 52 % yield of propylene carbonate was obtained.

The dry reforming of CH₄ (DRM) reaction can simultaneously convert two greenhouse gases CO₂ and CH₄ into high valued syngas. Nickel-based catalysts have been widely studied because of the low cost and high activity. However, carbon deposition making the deactivation of Ni-based catalyst is the main challenges for DRM reaction. This review illustrates DRM reaction mechanism and the causes of carbon deposition, as well as the resistance strategies of carbon deposition for Ni-based catalyst. The deposited carbon can be restrained by adjusting the size of Ni particles, introduction of promoters, reasonable design of support, controlling the reaction process and employing the confinement effect of the catalysts. The valuable insights are garnered for the further augmentation and optimization of the anti-carbon performance of catalysts by DFT and microkinetic. This work provides a tutorial for designing Ni-based catalysts with high anti-carbon deposition properties for DRM reaction.

Bioenergy with Carbon Capture, Utilization, and Storage (BECCUS) is an innovative technology that has the potential to contribute significantly to global climate change mitigation efforts by simultaneously removing atmospheric carbon dioxide through the process of biomass growth and combustion and generating sustainable energy in the form of electricity or fuel. This study systematically reviews existing research literature to identify the strengths and barriers to implementing BECCUS technology and explore potential countermeasures. The review revealed that BECCUS faces technological, socio-behavioral, policy-related, and financial issues that hinder its large-scale application. To address these challenges, the study highlights the need for further research to upscale BECCUS technology, dialogue, and participation among relevant stakeholders to improve public acceptance, and reforms to address regulatory bottlenecks in BECCUS project policies. The findings suggest that a multi-faceted approach, involving stakeholder engagement and policy reforms, is necessary to create an environment that fosters the advancement of current BECCUS technology and its optimal use in combating climate change, underlining the broader significance of this technology in the pursuit of a sustainable future. Effective stakeholder engagement can help identify and address the social, economic, and environmental concerns related to BECCUS, while targeted policy reforms can provide the necessary incentives and regulatory framework to support the development and deployment of this BECCUS.

Using CO₂-derived dimethyl carbonate (DMC) instead of diphenyl carbonate (DPC) as a carbonyl source for synthesizing bio-based polycarbonates is a green and cost-effective route. However, the synthesis of high-performance polycarbonates via the DMC route remains challenging due to the poor reactivity and selectivity of DMC compared to DPC. Herein, we designed a series of highly active protic ionic liquid (PIL) catalysts for the synthesis of poly(isosorbide carbonate) (PIC) from DMC with ISB. The influences of the structures of anion and cation on the catalytic activity of PILs were systematically studied. Compared with the reported aprotic IL catalysts, the unique reactive hydrogen of the cation in PILs could form a strong hydrogen bond interaction with the carbonyl group of DMC, resulting in higher reactivity of the carbonyl carbon of DMC. Moreover, the nucleophilicity of the anion could be easily tuned by adjusting the pK_a value, which effectively realized the balance of the reactivity difference between exo-OH and endo-OH in ISB. Among them, [DBUH][Im] showed the highest catalytic activity, and the weight-average molecular weight (M_w) and glass transition temperature of PIC reached 55,700 g/mol and 160 °C, respectively. Combined with NMR analyses and DFT calculations, the mechanism that exhibited the synergetic catalytic effect of anion-cation for the polymerization of DMC and ISB was presented.

Limestone decomposition is the first step in cement production, which produces a significant amount of CO₂ and poses a significant challenge to achieve carbon neutrality. Hydrogenation of limestone can produce CO or CH₄ instead of CO₂, which can be considered as a new way of carbon capture, making it a promising method for carbon emission reduction. In this work, pure CaCO₃ and several natural limestone samples were hydrolyzed under varying H₂ concentration using a micro fluidized bed (MFB) reactor combined with online mass spectrometry to reveal the mechanism and kinetics of limestone hydrogenation.

The main gases produced by hydrogenation at 1 atm are CO and CO₂. The CO₂ comes from the calcination of CaCO₃. The CO comes from 2 steps: the first step is the in-situ hydrogenation of CaCO₃ and the second step is the Reverse Water Gas Shift (RWGS) reaction. The activation energy (Ea) of CO₂ formation in H₂ atmosphere is lower than in Ar atmosphere. However, there is no obvious effect of different H₂ concentrations on the Ea of CO₂ formation. The Ea of CO in situ formation is 72.70 KJ/mol, 54.53 KJ/mol, 71.34 KJ/mol and 60.29 KJ/mol in 10%, 30%, 50% and 70% H₂ atmosphere, respectively. The H₂ concentration also has no significant effect on the in-situ CO evolution. However, the H₂ concentration can affect the Ea of CO produced by RWGS. The Ea is 75.67 KJ/mol, 167.59 KJ/mol and 221.47 KJ/mol in 10%, 30% and 50% H₂ atmosphere, and this reaction doesn't occur in 70% H₂ atmosphere. Compared with the pure CaCO₃, the hydrogenation of limestone can produce more CO and less CO₂. In limestone, impurity elements are the main factor affecting the reaction kinetics. Transition metals can increase the rate of CO₂ production, but have no apparent effect on CO. The CO₂ yield of high impurity limestone is higher than that of limestone with low impurities. Transition metals can also reduce the Ea of CO₂ formation and the RWGS reaction. In the 50% H₂ atmosphere, the Ea of CO₂ formation is 88.87 KJ/mol and the Ea of CO from RWGS is 137.60 KJ/mol. However, under the same conditions, the Ea of pure CaCO₃ is 126.91 KJ/mol and 221.47 KJ/mol.