Alumina supported platinum-ceria catalyst for reverse water gas shift reaction

Abstract

The activation of CO₂ molecules is a fundamental step for their effective utilization. Constructing high-density oxygen vacancies on the surface of reducible oxides is pivotal for the activation of CO₂. In this work, we prepared a series of 0.5PtxCe/Al₂O₃ (x=1, 5, 10, or 20) catalysts with varying Ce loading and 0.5 wt% of Pt for the reverse water gas shift (RWGS) reaction. The size of CeO₂ particle increases with Ce loading. Remarkably, the 0.5Pt5Ce/Al₂O₃ catalyst with an average CeO₂ particle size of 5.5 nm exhibits a very high CO₂ conversion rate (116.4×10⁻⁵ mol_CO2/(g_cat·s)) and CO selectivity (96.1%) at 600 °C. Our experimental findings reveal that the small-size CeO₂ in 0.5Pt5Ce/Al₂O₃ possesses a greater capacity to generate reactive oxygen vacancies, promoting the adsorption and activation of CO₂. In addition, the oxygen vacancies are cyclically generated and consumed during the reaction, which contributes to the elevated catalytic performance of the catalyst. This work provides a general strategy to construct rich oxygen vacancies on CeO₂ for designing high-performance catalysts in C₁ chemistry.