关键词: S-型异质结, 氧化钨/聚庚嗪酰亚胺, 双缺陷, 协同效应, 光催化机理

Abstract: Photocatalytic CO₂ reduction, which converts solar energy into chemical energy, represents a highly promising strategy. However, conversion efficiency is often constrained by the poor adsorption and activation of CO₂ and H₂O molecules. Here, we report an oxygen and nitrogen-vacancy-enriched WO₃/poly(heptazine imide) (PHI) S-scheme heterojunction for efficient and selective CO₂ photoreduction. The optimized WO₃/PHI heterojunction delivers a CO evolution rate of 129.2 μmol g^–1 h^–1 with 96.1% selectivity, corresponding to 7.9- and 6.5-fold enhancements over pristine WO₃ and PHI, respectively. Experiments and theoretical calculations demonstrate that the in-situ formed and photoinduced dual vacancies facilitate adsorption of CO₂ and H₂O, thereby improving the efficiency of photocatalytic CO₂ reduction. The interfacial W–N bonds serve as critical channels to accelerate interfacial charge transfer across the WO₃/PHI heterojunction. The S-scheme charge-transfer pathway, in concert with a dual-defect interfacial architecture, promotes charge transport, substantially boosting CO₂ reduction performance. This work provides mechanistic insight into defect-assisted S-scheme photocatalysis and offers a rational strategy for designing efficient photocatalysts for solar fuel production.

Key words: S-scheme heterojunction, WO₃/poly(heptazine imide), Dual defect, Synergistic effect, Photocatalytic mechanism