Room-Temperature Activation of CO₂ by Dual Defect-Stabilized Nanoscale Hematite (Fe_2?δO_3–v): Concurrent Role of Fe and O Vacancies

摘要

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.