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•Stable Co2C exhibits excellent ethanol selectivity and durability in CO2 hydrogenation.•Strong metal-support interaction (SMSI) obtained by the SiOCo bond formation ensures the ...stability of Co2C.•The formation of ethanol is derived from the insertion of CO into CHx intermediates.•CO can induce the regeneration and reconstruction of decomposed Co2C on supports.
Direct CO2 hydrogenation to ethanol is one of the promising and emerging routes for the transformation of CO2 into value-added chemicals, but it remains a major challenge because of low ethanol selectivity and catalytic stability. In this work, Na-promoted cobalt catalysts supported on different materials (Al2O3, ZnO, AC, TiO2, SiO2, and Si3N4) were evaluated to elucidate the effects of supports. The SiO2- and Si3N4-supported catalysts exhibited efficient generation of ethanol with 18% CO2 conversion and 62% selectivity in the alcohol distribution at 250 °C, whereas CH4 was predominantly produced on other supported catalysts. Characterization results indicated that the Co2C active phase only remained intact on SiO2 and Si3N4 supports during reaction and exhibited excellent durability for 300 h, which was attributed to the existence of a strong metal–support interaction (SMSI) obtained by SiOCo bond formation. In situ DRIFTS results revealed that CO produced on Co2C inserted into CHx intermediates to form ethanol. Moreover, CO as the reactive intermediate could induce the regeneration and reconstruction of decomposed Co2C on the surface for catalytic sustainability.
The Cover Feature shows the catalyst production process starting from a mixture of zeolitic imidazolate framework‐8 (ZIF‐8) and Ni2+ precursor, which is then pyrolyzed to yield the intermetallic ...Ni3ZnC catalyst. This intermetallic compound catalyzes the selective hydrogenation of CO2 into CO via the reverse water gas shift reaction pathway, while the most common methanation reaction pathway is suppressed, even at high pressure. The gain in selectivity is represented by the catalyst's being able to move the railway switch control towards CO. Image credit: Eliana R. de Almeida. More information can be found in the Full Paper by L. M. Rossi and co‐workers.
For CO2 hydrogenation over the graphene oxide (GO) modified In2O3 catalysts, GO promoted the transformation from cubic In2O3 (c-In2O3) to hexagonal In2O3 (h-In2O3). The c-In2O3(440)/h-In2O3(110) ...homojunction was formed between h-In2O3(110) and c-In2O3(440). The homojunction strengthened the interaction between the two phases, motivated the reduction of surface In2O3 and facilitated the generation of oxygen vacancies, which was greatly beneficial to the formation of methanol.
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•GO promoted the transform of c-In2O3 to h-In2O3 and inhibited the deep reduction of h-In2O3 to In.•The formation energy of oxygen vacancies on homojunction was lower than that of h-In2O3 or c-In2O3.•The highest STY of methanol could reach 0.93 gMeOHh−1gcat−1 on In2O3-8 wt% GO under 3 MPa and 350 °C.•The homojunction formed by c-In2O3(440) and h-In2O3(110) was conducive to the methanol formation.
The graphene oxide (GO) modified In2O3 composite catalyst was applied for CO2 hydrogenation to methanol. The GO significantly promoted the formation of hexagonal In2O3 (h-In2O3) and inhibited the deep reduction of h-In2O3 to element In. The homojunction formed by h-In2O3(110) and c-In2O3(440) strengthened the interaction between the two phases, motivated the reduction of surface In2O3 and facilitated the generation of oxygen vacancies, which was greatly beneficial to the formation of methanol. DFT manifested that the formation energy of oxygen vacancies on c-In2O3(440)/h-In2O3(110) homojunction was lower than that of single h-In2O3 or c-In2O3, indicating that more oxygen vacancies were easier to be generated at the two phases interface. For rod In2O3 catalysts modified by different GO content, when the GO content reached 8%, the space–time yield (STY) of methanol could be as high as 0.93 gMeOHh−1gcat−1, and the methanol selectivity could still reach more than 76% with CO2 conversion of 10.4%.
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•A wide variety of heterogeneous catalysts have been evaluated in the CO2 hydrogenation to methanol.•This review is on discussing metal-based catalysts, oxygen deficient materials and ...other novel catalytic system.•This review tries to provide a current understanding of catalyst design, catalytic performance and reaction mechanism.•We provide an overview of challenges and opportunities for future research associated with CO2 hydrogenation to methanol.
Catalytic transformations of carbon dioxide (CO2) to methanol with the help of hydrogen (H2), originates directly from renewable energy sources, is considered as one of the economic ways to alleviate the global warming and drive chemical and energy companies towards a more sustainable use of resources. Recently, a wide variety of heterogeneous catalysts have been evaluated in the CO2 hydrogenation to methanol. The focus of this perspective article is discussing three catalyst categories: (1) Metal-based catalysts, including modified Cu-based methanol catalysts and noble metals such as Au, Ag, Pd and Pt; (2) Oxygen deficient materials; (3) Other catalytic system with novel reaction mechanism and catalytic structure. In addition, this review tries to provide a current understanding of catalyst design, catalytic performance and reaction mechanism over various types of heterogeneous catalysts with an emphasis on practical aspects for the direct production of methanol from CO2 hydrogenation to methanol. We also provide an overview of the challenges and opportunities for future research associated with CO2 hydrogenation to methanol.
This study aims to evaluate and compare two integrated processes (Plant A and B) for hydrocarbon production from CO2. They involve proton exchange membrane water electrolysis for H2 production, ...reverse water-gas shift reaction for syngas production, pressure swing adsorption for syngas purification, Fischer-Tropsch synthesis for diesel-range hydrocarbons from CO2, and atmospheric distillation for product separation. Plant B additionally integrates a hydrocracking-based upgrading section. The simulations were performed using Aspen Plus® v10, Aspen Adsorption® v10, and Aspen Custom Modeler® v10. The evaluation covers technical, economic, environmental, and multi-criteria assessment (GREENSCOPE). The proposed processes demonstrate the potential to convert CO2 to hydrocarbons, with carbon conversion rates of 75% and 71% for Plants A and B, respectively. Process energy intensity is 155 and 170 MJ/kgLP for Plants A and B, respectively. Environmental assessment reveals CO2 reduction, resulting in negative global warming potentials of −2.20 and −0.84 kgCO2-eq/kgLP for Plants A and B, respectively. The sustainability degree indices for Plants A and B are 1.00 and 0.06, respectively, indicating Plant A as the more sustainable process alternative based on both quantitative and qualitative metrics. Economic analysis shows project unviability in the Brazilian context due to reliance on H2 production and prevailing pricing conditions. Economic viability requires a price increase of liquid products by 266% and 302% or CO2-eq abatement costs ranging from 2.05 to 3.43 US$/kgCO2-eq for Plants A and B, respectively. GREENSCOPE methodology indicates better performance for Plant A across all scores, highlighting a clear connection between the hydrocracking unit and performance indicators. The findings show that these processes align with sustainable development goals (SDGs) targets for climate action (SDG 13), clean energy (SDG 7), industry, innovation, and infrastructure (SDG 9), decent work and economic growth (SDG 8), and responsible consumption and production (SDG 12). Overall, the research moves forward SDGs by offering solutions to cut carbon emissions and promote sustainable industrial practices.
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•The overall carbon conversion achieved 71–75%.•The global warming potential is about −2.20 to −0.84 kgCO2-eq/kgLP.•The net present value is about −1066 to −1147 MMUS$.•An increase of 266–302% in liquid product prices is required for economic viability.•A CO2-eq abatement cost of 2.05–3.43 US$/kg is required for economic viability.
NaTaO3 (ABO3)-based catalysts with B-site substituted metals M= (Co, Ni, Fe, Ga, Ti) for photothermal-catalyzed carbon dioxide reduction hydrogenation to C1 products were prepared via a simple ...one-step hydrothermal method. The B-site metal doping catalysts exhibited excellent performance for the aimed photothermal catalytic reaction. Among them, the NaTa0.9Co0.1O3 was the most eye-catching catalyst with a stable crystal cell, an excellent heterojunction structure, and a bandgap structure for light absorption, The fine structure properties results in a low electron-hole recombination rate and high photoelectron transfer efficiency under light conditions. The suitable alkaline adsorption sites and thermal reduction properties also be the effective assistance for the catalytic process. The CO yield and CH4 yield of the NaTa0.9Co0.1O3 catalyst were 6.6 times and 120 times higher than those of the pure-phase NaTaO3, respectively, and the CH4 selectivity was up to 98% under the illumination condition of 300 ℃. For the photothermal hydrogenation reaction, thermal catalysis dominates the reaction, and light illumination promotes the generation and transfer of photogenerated electrons and improves the catalyst stability. The above studies show that NaTaO3 based perovskite has a great potential in the field of photothermal catalyzed carbon dioxide reduction.
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•B-site doped perovskite photothermal catalysts were prepared by a one-pot method.•The introduction of metallic Co doping greatly improves CO and CH4 yields.•Photocatalysis and thermocatalysis synergize to promote CO2 reduction.•The mechanism of action of photothermal catalytic synergy was explored.•The reasons for metal doping to improve catalytic performance were discussed.
In the future we will be phasing out the use of fossil fuels in favour of more sustainable forms of energy, especially solar derived forms such as hydroelectric, wind and photovoltaic. However, due ...to the variable nature of the latter sources which depend on time of day, and season of the year, we also need to have a way of storing such energy at peak production times for use in times of low production. One way to do this is to convert such energy into chemical energy, and the principal way considered at present is the production of hydrogen. Although this may be achieved directly in the future via photocatalytic water splitting, at present it is electrolytic production which dominates thinking. In turn, it may well be important to store this hydrogen in an energy dense liquid form such as methanol or ammonia. In this brief review it is emphasised that CO2 is the microscopic carbon source for current industrial methanol synthesis, operating through the surface formate intermediate, although when using CO in the feed, it is CO which is hydrogenated at the global scale. However, methanol can be produced from pure CO2 and hydrogen using conventional and novel types of catalysts. Examples of such processes, and of a demonstrator plant in construction, are given, which utilize CO2 (which would otherwise enter the atmosphere directly) and hydrogen which can be produced in a sustainable manner. This is a fast‐evolving area of science and new ideas and processes will be developed in the near future.
Methanol synthesis: This Minireview describes the mechanism of methanol synthesis, and considers a way of synthesizing methanol from sustainable, non‐fossil hydrogen. This combines electrolysis of water using solar energy, combined with CO2 garnered from a coal power plant. It covers the synthesis of traditional CZA (Cu−Zn−Al) based catalysts and the possibilities for novel materials.
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•In-Zr/SAPO-34 catalysts were used for direct CO2 hydrogenation to lower olefins.•In-Zr composite oxides were prepared with the introduction of different Zr content.•A selectivity for ...C2=–C4= was up to 80% in hydrocarbons with 2% CH4 and 64% CO.•The addition of a certain amount of Zr can markedly enhance catalytic performance.
Direct production of lower olefins (C2=−C4=: ethylene, propylene and butylene), basic carbon-based building blocks, from carbon dioxide (CO2) hydrogenation is highly attractive, although the selectivity towards olefins has been too low. Here we present a series of bifunctional catalysts contained indium-zirconium composite oxides with different In:Zr atomic ratios and SAPO-34 zeolite, which can achieve a selectivity for C2=–C4= as high as 65–80% and that for C2–C4 of 96% with only about 2.5% methane among the hydrocarbon products at CO2 conversion of 15–27%. The selectivity of CO via the reverse water gas shift reaction is lower than 70%. The product distribution is completely different from that obtained via CO2-based Fischer-Tropsch synthesis and deviates greatly from the classical Anderson-Schulz-Flory distribution. The zirconium component plays a critical role in determining the physicochemical properties and catalytic performance of bifunctional catalysts. Catalyst characterization and density functional theory calculations demonstrate that the incorporation of a certain amount of zirconium can create more oxygen vacancy sites, stabilize the intermediates in CO2 hydrogenation and prevent the sintering of the active nanoparticles, thus leading to significantly enhanced catalytic activity, selectivity of hydrocarbons and stability for direct CO2 hydrogenation to lower olefins at the relatively high reaction temperature of 380 °C.
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•Ionic Liquids favor the production of acid formic and methanol from CO2 hydrogenation.•Ionic Liquids improve product yields to ~ 65% for formic acid and ~ 68% for methanol.•CO2 ...hydrogenation occurs at ambient temperature and low pressure conditions.•Methanol is produced with less stoichiometric hydrogen requirement.
Direct hydrogenation of carbon dioxide (CO2) to formic acid is unfavorable thermodynamically, which makes its production limited. In this study, a thermodynamic analysis of CO2 hydrogenation to binary product systems of methanol and formic acid promoted by ionic liquid (IL) (1-ethyl-2,3-dimethylimidazolium nitrite, (EdmimNO2) is presented. The analysis is conducted in Aspen Plus using the Gibbs energy minimization approach combined with a vapor–liquid equilibrium (VLE) for the solvation of CO2 in IL. It is demonstrated that solvating CO2 in ILs is an attractive alternative to overcome the thermodynamic difficulty associated with the product yield, especially formic acid. The EdmimNO2 promoted system is very effective for the simultaneous production of formic acid and methanol at 25 °C and 17 bar with a yield of 35% formic acid and 30% methanol at a CO2/H2/IL ratio of 1/2/2. The results show a marked improvement in the yield of formic acid to other previously conducted studies on formic acid production.
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