Room-Temperature Activation of CO2 by Dual Defect-Stabilized Nanoscale Hematite (Fe2−δO3–v): Concurrent Role of Fe and O Vacancies

We demonstrate that synthetically controlled concurrent stabilization of Fe and O vacancy defects on the surface of interbraided nanoscale hematite (Fe 2-δ O 3- v ) renders an interesting surface chemistry which can reduce CO 2 to CO at room temperature (RT). Importantly, we realized a highly enhanced output of 410 μmol h -1 g -1 at RT, as compared to that of 10 μmol h -1 g -1 for bulk hematite. It is argued based on the activity degradation under cycling and first principles density functional theory calculations that the excess chemical energy embedded in the defect-stabilized surface is expended in this high-energy conversion process, which leads to progressive filling up of oxygen vacancies.