NiFe-PBA/NiS2/NiO S-scheme heterojunction for efficient photocatalytic hydrogen production

Abstract

Photocatalytic hydrogen evolution technology is gradually emerging as a promising strategy to alleviate energy challenges, serving as an inherently sustainable clean energy technology that also aids in the progress of sustainable development. In this paper, a low-temperature mixing method was effectively employed to construct a highly efficient noble-metal-free 3-NiFe-PBA/NiS₂/NiO heterojunction photocatalyst for rapid transfer of photogenerated carriers. Under the irradiation of a 5 W LED light, the optimized 3-NiFe-PBA/NiS₂/NiO photocatalyst exhibited a hydrogen production efficiency of 3238.635 μmol·g^-1·h^-1, which was 10.08, 4.59, and 1.85 times higher than that of NiO, NiFe-PBA, and NiS₂/NiO, respectively. The existence of a strong built-in electric field at the interface between NiFe-PBA and NiO was confirmed by X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) analyses, and the S-scheme heterojunction mechanism of 3-NiFe-PBA/NiS₂/NiO was proposed. Additionally, the NiS₂ cocatalyst provided abundant active sites for the photocatalyst. Upon light irradiation, the combination of NiFe-PBA and NiS₂/NiO not only broadened the light absorption but also significantly prolonged the lifetime of photogenerated carriers through the synergistic effect of the NiS₂ cocatalyst, the built-in electric field, and the S-scheme heterojunction mechanism. This study offers a novel design concept for the development of highly efficient bimetallic PBA S-scheme heterojunction photocatalysts.