CuNiCoAlLaOx/Zn0.5Cd0.5S heterojunction photocatalytic system: Synergistic effects driving efficient and stable photocatalytic hydrogen production

CuNiCoAlLa-HEO@Zn 0.5 Cd 0.5 S Schottky heterojunction photocatalysts for H 2 evolution. • Optimal CH-10 yields 9.73-fold higher H 2 than Zn 0.5 Cd 0.5 S with stable cycling. • Dispersed multi-metals broaden absorption, lower resistance and inhibit photocorrosion. • Spontaneous electron transfer from Zn 0.5 Cd 0.5 S to HEO creates built-in field. • Interfacial Schottky barrier and multi-metal synergy promote surface HER kinetics. Hydrogen production through photocatalytic water splitting serves as a critical means of harnessing solar energy and producing clean fuels. Nevertheless, traditional photocatalysts are greatly hampered by the rapid recombination of photogenerated charge carriers, sluggish interfacial charge transfer, and insufficient long-term stability. In this study, a quinary high-entropy oxide CuNiCoAlLaO X was successfully synthesized via a coprecipitation method, and thereafter incorporated with Zn 0.5 Cd 0.5 S by employing a mechanical mixing followed by solvent evaporation, thereby constructing a CuNiCoAlLaO X /Zn 0.5 Cd 0.5 S Ohmic junction photocatalytic system. The composition of the high-entropy oxide and its interfacial interaction with Zn 0.5 Cd 0.5 S were systematically investigated, with a focus on photocatalytic hydrogen production performance and stability. In a lactic acid sacrificial system, the optimized high-entropy composite catalyst exhibited outstanding capability of generating hydrogen, achieving a cumulative hydrogen production of 261.59 μmol over 5 h, with a hydrogen production rate approximately 9.73 times higher than that of pristine Zn 0.5 Cd 0.5 S. Comprehensive characterizations including XRD, SEM, and TEM confirmed that the composite possesses well-defined phase structures and uniformly dispersed metal elements, demonstrating the reliability and reproducibility of the preparation process. Furthermore, UV-Vis diffuse reflectance spectroscopy and photoelectrochemical measurements validated the broad-spectrum light absorption and efficient charge carrier separation as key advantages of the composite. This work highlights the promising potential of high-entropy oxide-based composite catalysts and provides important experimental evidence and a viable technological pathway for the development of low-cost, highly stable photocatalytic materials for hydrogen production.