Evaluating metal oxide support effects on the RWGS activity of Mo2C catalysts

Abstract

The reverse water gas shift reaction (RWGS) is an important first step in the thermochemical transformation of CO₂ to fuels. Recent research efforts have investigated transition metal carbides due to their high activity and terrestrial abundance. In order to improve particle dispersion and mechanical stability, the catalysts are often deposited onto high surface area metal oxide supports. Understanding the influence the oxide support has on the observed catalytic activity is imperative for increased efficiency. Herein, we investigate the effect of the oxide support's (γ-Al₂O₃, SiO₂, ZrO₂, CeO₂, and MgO) reducibility and acidity on potassium promoted molybdenum carbide catalysts for the RWGS. Additionally, DFT computation was used to evaluate CO and CO₂ adsorption energies at a model interface of Mo₂C/MgO. It is demonstrated that non-reducible and acidic supports are the most active for the production of CO with K–Mo₂C/Al₂O₃ showing the highest CO site time yield of 55.6 min⁻¹.