Promoted reverse water-gas shift activity on transition metals-incorporated iron-cerium oxide solid solution catalyst

Abstract

Earth-abundant Fe oxide-based catalysts, renowned for their broad-spectrum light absorption, hold promise for driving the photothermal RWGS reaction—a promising strategy for converting CO₂ emissions into valuable carbonaceous feedstocks. However, traditional Fe oxide-based catalysts exhibit limited activity due to their constrained H₂ dissociation and CO₂ activation capabilities, especially at lower temperatures. This study introduces Co, Ni, and Cu-doped Ce_0.7Fe_0.3O₂ solid-solution catalysts. Incorporation of Fe into CeO₂ enhances CO₂ dissociation while preserving extensive light adsorption up to 2500 ​nm. Notably, Co doping enhances H₂ dissociation and promotes CO₂ activation. Subsequent investigations reveal that a catalyst doped with 5 ​mol% Co exhibits the highest photothermal catalytic activity, attaining a ∼50 ​% CO₂ conversion under 300 ​W Xe-lamp irradiation with excellent selectivity and stability over 10 reaction cycles spanning 10 ​h. These results underscore the potential of designing CeO₂-based solid solution catalysts with synergistic metal dopants for efficient and selective CO₂ conversion under moderate conditions.