Rationally designed CaTiO/MnCdS/NiC S-scheme/Schottky integrated heterojunction for efficient photocatalytic H evolution.

Developing effective photocatalysts to achieve stable and efficient solar-induced hydrogen production remains a significant challenge due to rapid photocarrier recombination and sluggish hydrogen evolution kinetics. Here, a multi-interfacial engineering strategy involving the decoration of metallic NiC onto CaTiO/MnCdS was proposed to create an S-scheme/Schottky hybrid heterostructure with multiple carrier transport paths for effective photocatalytic H production. Exploiting the synergy between S-scheme heterojunction and Schottky barrier, the engineered ternary CaTiO/MnCdS/NiC hybrid heterojunction exhibits outstanding photostability and significantly enhanced hydrogen evolution activity of 79.1 mmol g h, which was about 4.55, 3.22 and 2.59 times greater than MnCdS, MnCdS/NiC, and CaTiO/MnCdS, respectively. By creating an S-scheme heterojunction between CaTiO and MnCdS, accompanied by a robust internal electric field (IEF), spatial charge separation can be effectively accelerated while ensuring the simultaneous preservation of highly active electrons and holes. Meanwhile, NiC nanoparticles, acting as a Schottky-junction H generation cocatalyst, can efficiently trap the photoinduced electrons to establish multiple charge transfer channels and supply ample active sites for photoreduction reaction, thereby further optimizing the hydrogen generation kinetics. The integration of a Schottky barrier and S-scheme heterojunction in this research is expected to offer new perspectives for designing other highly effective hybrid catalysts for solar-to-hydrogen fuel conversion.