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 molCO2/(gcat·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.