Enhanced photocatalytic hydrogen production and simultaneous benzyl alcohol oxidation by modulating the Schottky barrier with nano high-entropy alloys

Catalysts play a vital role in photocatalytic water-splitting by converting solar energy into storable chemical energy. In this study, we successfully synthesized an HCN/HEA heterostructure by rationally combining the Pt18Ni26Fe15Co14Cu27 nano-high-entropy alloy (HEA) as an effective cocatalyst with protonated g-C3N4 (HCN) nanosheets, via an electrostatic self-assembly method. The resulting HCN/HEA exhibited remarkable performance in both photocatalytic H2 production and selective oxidation of benzyl alcohol to benzaldehyde. The integration of HEA into HCN leads to the formation of Schottky junctions, which can significantly accelerate charge migration and reduce the recombination of charge carriers. Further investigations using in situ surface photovoltage imaging demonstrated that the reducing cocatalyst HEA can act as a photogenerated electron trap. The best HCN/HEA heterojunction exhibited excellent photocatalytic hydrogen production activity, reaching 2.4 mmol g−1 h−1 and an impressive benzaldehyde production rate of 5.44 mmol g−1 h−1. These values were 958 and 6.6 times higher than those achieved with pristine HCN, respectively. This study offers promise for the rational design of high-performance cocatalysts to improve the transport, separation, and utilization of light-release charge carriers.