Unmatched Redox Activity of the Palladium-Doped Indium Oxide Oxygen Carrier for Low-Temperature CO2Splitting

The chemical conversion of CO2into value-added products is the key technology to realize a carbon-neutral society. One representative example of such conversion is the reverse water–gas shift reaction, which produces CO from CO2. However, the activity is insufficient at ambient pressure and lower temperatures (<600 °C), making it a highly energy-intensive and impractical process. Herein, we report indium oxide nanofibers modified with palladium catalysts that exhibit significantly potent redox activities toward the reduction of CO2splitting via chemical looping. In particular, we uncover that the doped palladium cations are selectively reduced and precipitated onto the host oxide surface as metallic nanoparticles. These catalytic gems formed operando make In2O3lattice oxygen more redox-active in H2and CO2environments. As a result, the composite nanofiber catalysts demonstrate the reverse water–gas shift reaction via chemical looping at record-low temperatures (≤350 °C), while also imparting high activities (CO2conversion: 45%). Altogether, our findings expand the viability of CO2splitting at lower temperatures and provide design principles for indium oxide-based catalysts for CO2conversion.