Defect-band bridge photothermally activates Type III heterojunction for CO2 reduction and typical VOCs oxidation

Abstract

This work reports a novel strategy to activate type III heterojunction through introducing defect sites at the interfaces and making use of the defect band as the bridge for storage, secondary excitation, and interband transfer of the photothermal induced charges for constructing two-component Type B heterojunction photothermocatalyst. Type III heterojunction WO3−x/GdCrO3 is activated by defect-band state W5/4+ at WO3−x interface under photothermal conditions, achieving efficient charge separation, high redox potential, and full visible light absorption. The as-bridged (or Type B) heterojunction WO3−x-R/GdCrO3 as non-noble metal catalyst demonstrates excellent photothermocatalytic performance in toluene degradation with a reaction rate five times higher than that of WO3−x/GdCrO3 with less interfacial defect sites as well as in CO2 reduction with high CO and CH4 yielding rates of 49.6 μmol g−1 h−1 and 18.5 μmol g−1 h−1 in gas-solid reaction system without sacrifice agent, evidently better than those reported in the literature.