Electronically Activated CuFeO2 via Graphene Oxide for Highly Efficient CO2 Conversion into Long-Chain Hydrocarbons

Abstract

Utilizing CO₂ as a feedstock to produce valuable chemicals and fuels provides a potential alternative to traditional methods reducing dependence on petroleum resources. It has been acknowledged that incorporating the reverse water gas shift (RWGS) and Fischer–Tropsch synthesis (FTS) active phase in a tandem system is crucial for optimizing the efficiency of CO₂ hydrogenation. The formation of RWGS and FTS active phases in catalysts often involves creating an electron-rich local environment. In this study, graphene oxide (GO)-supported CuFeO₂ was in situ synthesized under hydrothermal conditions (CuFeO₂/GO-H), achieving an intimate interface and thus facilitating the electron transfer from GO to CuFeO₂. The CuFeO₂/GO-H exhibits a CO₂ conversion of 36.8% and a C₅₊ selectivity of 66.0%, which are 1.6 and 1.4 times higher than those of pristine CuFeO₂. The augmented CO₂ hydrogenation performance of CuFeO₂/GO-H is credited to the electron transfer facilitated by the cation−π interaction between CuFeO₂ and surface oxygen-containing groups on GO. The electron transfer from GO to CuFeO₂ not only boosts the adsorption of CO₂ and CO but also promotes the reduction and carburization of CuFeO₂ to form more small-sized Cu-χ-Fe₅C₂ active sites. In addition, the layer structure of GO with certain defects ensures a close proximity between the supported active phases, facilitating the formation of small-sized Cu and χ-Fe₅C₂ nanoparticles, as well as the exposure of Cu-χ-Fe₅C₂ interfaces. The small particle size and well-integrated Cu and χ-Fe₅C₂ in CuFeO₂/GO-H enhance its CO₂ conversion and C₅₊ selectivity by providing more active sites and reducing the kinetic barriers for C–C coupling. This study aligns with efforts to design bifunctional catalysts by emphasizing the electron transfer process in optimizing the rate of CO₂ hydrogenation.