Room-Temperature Activation of CO2 by Dual Defect-Stabilized Nanoscale Hematite (Fe2-delta O3-v): Concurrent Role of Fe and O Vacancies

Abstract

We demonstrate that synthetically controlled concurrent stabilization of Fe and O vacancy defects on the surface of interbraided nanoscale hematite (Fe2-delta O3-v) renders an interesting surface chemistry which can reduce CO2 to CO at room temperature (RT). Importantly, we realized a highly enhanced output of 410 mu mol h(-1) g(-1) at RT, as compared to that of 10 mu mol 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.