Ethanol synthesis <i>via</i> catalytic CO₂ hydrogenation over multi-elemental KFeCuZn/ZrO₂ catalyst

Abstract

Technological enablers that use CO₂ as a feedstock to create value-added chemicals, including ethanol, have gained widespread appeal. They offer a potential solution to climate change and promote the development of a circular economy. However, the conversion of CO₂ to ethanol poses significant challenges, not only because CO₂ is a thermodynamically stable and chemically inert molecule but also because of the complexity of the reaction routes and uncontrollability of C-C coupling. In this study, we developed an efficient catalyst, K-Fe-Cu-Zn/ZrO₂ (KFeCuZn/ZrO₂), which enhances the EtOH space time yield (STY_EtOH) to 5.4 mmol g_cat ^-1 h^-1, under optimized conditions (360 °C, 4 MPa, and 12 L g_cat ^-1 h^-1). Furthermore, we investigated the roles of each constituent element using <i>in situ</i>/<i>operando</i> spectroscopy such as X-ray absorption spectroscopy (XAS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). These results demonstrate that all components are necessary for efficient ethanol synthesis.