Hydrogen-bonded CdSe/PDI with double electric field synergism for enhanced overall water splitting performance

Abstract

The Z-scheme heterojunction is the preferred structure for overall water splitting (OWS) as it can improve the overall catalyst redox capacity and effectively separate photogenerated electron–hole pairs. In this paper, we synthesized CdSe/PDI Z-scheme heterojunction structures with a double electric field synergistic effect for photocatalytic OWS. The rates of hydrogen and oxygen generation are as high as 120.7 and 60.6 μmol g⁻¹ h⁻¹, respectively. The improved OWS performance can be attributed to the hydrogen bond located at the CdSe/PDI interface coupling the interfacial electric fields and bulk electric fields of PDI in the same direction. The hydrogen bonds strengthen the interfacial stability, and the synergistic effect of the dual electric fields accelerates the separation and transport of photogenerated electrons and holes, enriched in CdSe and PDI, respectively. This structure realizes the spatial separation of proton reduction and water oxidation reactions, effectively reduces the inverse and side reactions of the total water decomposition process, and improves the overall catalytic performance. The organic–inorganic hybridized photocatalytic semiconductor constructed by hydrogen bonding advances OWS research.