Experimental and Computational Synergistic Design of Cu and Fe Catalysts for the Reverse Water–Gas Shift: A Review

Abstract

Strategies to capture and sequester ever-increasing anthropogenic CO2 emissions include adsorbing CO2 onto inorganic substrates and then storing it in reservoirs, changing land use to promote forestry, and converting CO2 to chemicals and fuels. The reverse water–gas shift (RWGS) reaction is a conversion strategy for producing CO from CO2 that provides the highest technology readiness level. Cu and alkali metals promote CO2 adsorption, Fe improves the thermal stability, and reducible supports like CeO2 accelerate the reaction rate. Density functional theory (DFT) is a practical modeling tool for evaluating the catalytic properties of materials at the atomic scale. The active phases of the Cu- and Fe-based catalysts, the effect of bimetallic compositions, the presence of promotors, and the influence of the support material are evaluated using observations from DFT simulations and experimental data. An optimal RWGS catalyst favors (1) CO2 adsorption, (2) the dissociation of CO2 or intermediate carbonate species to CO, and (3) CO desorption. Typically, a single-component catalytic plane is unfavorable for all these criteria, thus necessitating the design of an optimal multicomponent RWGS catalyst. Future DFT research is directed toward multifacet catalytic systems to understand the structural configuration of a highly active RWGS system. Experimental and characterization results complement DFT studies in the design of the optimal RWGS catalyst. Machine learning trained by literature data provides an automated approach for the inverse design of high-performance, stable, and economic catalysts for the RWGS reaction. This review encompasses experimental and computational approaches to understand the activity of RWGS catalysts.

Double-Edged Sword Effect of Classical Strong Metal–Support Interaction in Catalysts for CO2 Hydrogenation to CO, Methane, and Methanol

“…The thermocatalytic process of CO 2 hydrogenation at atmospheric pressure consists of two competitive reactions, which are reverse water–gas shift (RWGS) and the Sabatier reaction. ,− The RWGS is an endothermic reaction (CO 2 + H 2 → CO + H 2 O Δ H 298 K = 41.2 kJ mol –1 ) for the production of CO at relatively high temperatures (>500 °C). ,, CO is a key precursor to synthesize more-complex energy products, such as the production of liquid fuels through Fischer–Tropsch (FT) synthesis. , The mainstream catalysts employed for the RWGS reaction can be classified into two groups that are Cu-based and noble-metal-based catalysts. Despite the inexpensive Cu-based catalysts exhibiting satisfactory activity in RWGS reaction, their poor stability at high temperatures limits their practical application .…”

Clever Nanomaterials Fabrication Techniques Encounter Sustainable C1 Catalysis

“…On the one hand, the reverse water−gas shift (RWGS) reaction (CO 2 + H 2 → CO + H 2 O) enables the transformation of CO 2 into CO, which can be well linked to the syngas conversion process described above. 15,16 On the other hand, the tandem catalysis concept as mentioned in syngas conversion is also suitable for the transformation of CO 2 + H 2 into light olefins, aromatics, isoparaffins, etc. in a one-pass process.…”

“…Fischer–Tropsch synthesis (FTS) stands out among various syngas conversion pathways due to its high efficiency, product diversity, and successful industrialization. − Tandem catalysis is another promising strategy for syngas conversion, in which the bi- or multifunctional catalysts guarantee the direct conversion of syngas into targeted product in a single pass with alkenes or methanol as the key intermediates. , Second, for the conversion of greenhouse gas CO 2 , thermal-catalytic CO 2 hydrogenation technology with the aid of sustainable energy-powered green H 2 has attracted more and more attention owing to its carbon elimination function and strong industrial applicability, which is expected to open up a new paradigm for sustainable and recyclable development. , CO 2 is inextricably related to syngas conversion. On the one hand, the reverse water–gas shift (RWGS) reaction (CO 2 + H 2 → CO + H 2 O) enables the transformation of CO 2 into CO, which can be well linked to the syngas conversion process described above. , On the other hand, the tandem catalysis concept as mentioned in syngas conversion is also suitable for the transformation of CO 2 + H 2 into light olefins, aromatics, isoparaffins, etc. in a one-pass process. − …”

Defect-Driven Efficient Selective CO2 Hydrogenation with Mo-Based Clusters

“…Tailored multicomponent catalysts, including Cu and Fe alloys, were also commonly seen to promote the RWGS performance, where Cu promotes CO 2 activation, and normally leads to the formate mechanism for the hydrogenation, while Fe improves the thermal stability and was found to favor redox mechanism for hydrogenation. Alkali metals were frequently doped to improve CO 2 adsorption and suppress excess adsorption of H 2 , leading to methanation. , …”