Enhanced photocatalytic hydrogen production activity of Janus Cu1.94S-ZnS spherical nanoheterostructures.

Photocatalytic hydrogen evolution is one of the most promising approaches for efficient solar energy conversion. The light-harvesting ability and interfacial structure of heterostructured catalysts regulate the processes of photon injection and transfer, which further determines their photocatalytic performances. Here, we report a Janus Cu1.94S-ZnS nano-heterostructured photocatalyst synthesized using a facile stoichiometrically limited cation exchange reaction. Djurleite Cu1.94S and wurtzite ZnS share the anion skeleton, and the lattice mismatch between immiscible domains is ∼1.7%. Attributing to the high-quality interfacial structure, Janus Cu1.94S-ZnS nanoheterostructures (NHs) show an enhanced photocatalytic hydrogen evolution rate of up to 0.918 mmol h-1 g-1 under full-spectrum irradiation, which is ∼38-fold and 17-fold more than those of sole Cu1.94S and ZnS nanocrystals (NCs), respectively. The results indicate that cation exchange reaction is an efficient approach to construct well-ordered interfaces in hybrid photocatalysts, and it also demonstrates that reducing lattice mismatch and interfacial defects in hybrid photocatalysts is essential for enhancing their solar energy conversion performance.