Improved reverse water-gas shift chemical looping performance of Co-In-based oxygen carriers supported on ceria

Abstract

Indium-based oxygen carriers supported on various oxides were evaluated for the reverse water-gas shift chemical looping (RWGS-CL) at 773 K. Among the materials investigated, 20wt% CoIn2/CeO2 showed superior performance, achieving high CO yield and space-time yield, and stable cyclic operation. Comparative studies revealed that, under RWGS-CL conditions, In species supported on CeO2 exhibited spontaneous redispersion, a behaviour not observed on other oxide supports (γ-Al2O3, rutile-TiO2, anatase-TiO2, and SiO2). This redispersion led to the formation of a highly dispersed In surface during operation, which is associated with enhanced CO formation through improved contact with CO2. Furthermore, Co was found to accelerate the reduction kinetics of In species, likely by promoting H2 dissociation and hydrogen spillover, while exerting little influence on oxidation kinetics. These results demonstrate that support-dependent dynamic structural changes play a key role in determining RWGS-CL performance.