Ni_0.85Se/Cd_0.9Zn_0.1S S-scheme heterojunction photocatalysts with photothermal effect for efficient photocatalytic...

The recombination of photogenerated carriers is the core bottleneck limiting the photocatalytic water splitting for hydrogen production. The S-scheme heterojunction can drive the directional migration of carriers through its built-in electric field, suppress recombination, and thereby enhance the charge utilization efficiency. In this study, one-dimensional Cd_0.9Zn_0.1S (CZS) nanorods were coupled with Ni_0.85Se (NS) particles with photothermal effect, constructing an NS/CZS S-scheme heterojunction photocatalyst. The nanorod shape of CZS shortens the electron transport path, thus shrinking the diffuse time to the surface and suppressing recombination of charges. The S-scheme heterojunction increases the spatial separation degree of photogenerated carriers, enabling high-energy electrons to accumulate in the conduction band of CZS to drive the hydrogen evolution. The photothermal effect of NS elevates the local surface temperature of NS/CZS particles, which reduces the reaction activation energy and accelerates the reaction kinetics. Under visible light, NS/CZS-5 with the optimal component achieves a hydrogen production rate of 325.02 mmol g^-1 and exhibits excellent cyclic stability. Density functional theory calculations further reveal the interfacial charge transfer mechanism, providing a new paradigm for the synergistic enhancement of photocatalytic hydrogen production through photothermal-heterojunction coupling.