An efficient improvement for photocatalytic hydrogen peroxide production: Sulfur vacancies in CaIn2S4
Yue Mao, Jian Zhang, Yingji Zhao, Xiaoqian Wei, Dong Jiang, Liyang Zhu, Yusuke Asakura, Quan Manh Phung, Ho Ngoc Nam, Hsien‐Yi Hsu, Yusuke Yamauchi
Abstract
Visible-light-driven hydrogen peroxide (H 2 O 2 ) synthesis is a sustainable and economically viable strategy for green production. However, most metal sulfide semiconductors exhibit insufficient band potentials, limiting selectivity and quantum yield . Here, we introduce sulfur vacancies into CaIn 2 S 4 to modify its band structure , enhancing the conduction band’s reduction capability and shifting oxygen reduction from a single direct 2e − pathway to a dual-pathway mechanism. This adjustment improves electron utilization efficiency. Theoretical calculations reveal that sulfur vacancies act as electron traps , promoting charge separation and suppressing recombination. Structural and electronic characterizations confirm these effects, and as a result, sulfur-vacancy-rich CaIn 2 S 4 (CaIS SV) achieves a photocatalytic H 2 O 2 production rate 9-fold than that of pristine CaIn 2 S 4 .