Refining the surface O defect via Cu on WO3 hollow sphere for photocatalytic CO2 reduction

Photocatalytic CO 2 reduction is a promising strategy for achieving carbon neutrality. Nevertheless, its efficiency is limited by the high energy barrier and severe charge recombination. Herein, Cu–WO 3 hollow sphere hybrids, in which Cu is anchored to the O defects of WO 3 , were fabricated to enable efficient photocatalytic conversion of CO 2 to CO. The oxygen defects in WO 3 promote the preferential deposition of Cu, resulting in the simultaneous exposure of Cu–O defect active sites. In the engineered Cu–WO 3 structure, the confined hollow morphology improves CO 2 adsorption and facilitates the separation of photogenerated electrons and holes. The Cu–O defect centers effectively reduce the overpotential for CO 2 conversion. Consequently, the synthesized Cu–WO 3 catalyst demonstrates excellent and stable photocatalytic CO 2 reduction activity, achieving a CO production rate of 1518 μL g –1 h –1 in the absence of a sacrificial agent, which is 5.2 times greater than that of pristine WO 3 . This study provides new insights into defect modulation for designing highly efficient photocatalytic materials.