L-Cysteine capped Mo2C/Zn0.67Cd0.33S heterojunction with intimate covalent bonds enables efficient and stable H2-Releasing photocatalysis

[Display omitted] •L-Cysteine capped Mo2C was used to anchor Zn2+/Cd2+ to in-situ construct a robust heterojunction.•A strong internal electric field facilitates spatially separated redox sites of heterojunction.•L-Mo2C/Zn0.67Cd0.33S heterojunction suppresses the photo-corrosion of Zn0.67Cd0.33S photocatalyst.•AQY of L-Mo2C/Zn0.67Cd0.33S-5 is as high as 33.03% at 420 nm. ZnxCd1-xS is a prospective photocatalyst with wide visible-light absorption up to 500 nm, but its stability and activity are still facing huge challenges. Herein, L-Cysteine capped Mo2C (L-Mo2C) nanoplates were used to anchor Zn2+/Cd2+ to in-situ grow Zn0.67Cd0.33S nanomaterial for constructing a highly efficient and robust L-Mo2C/Zn0.67Cd0.33S heterojunction through intimate Mo-S covalent bonds for photocatalytic hydrogen evolution reaction (HER). This work not only suppresses the photo-corrosion of Zn0.67Cd0.33S nanomaterial by the construction of strong L-Mo2C/Zn0.67Cd0.33S Schottky heterojunction but also greatly improves the charge transfer efficiency by generating a strong internal electric field. As a result, the optimized L-Mo2C/Zn0.67Cd0.33S-5 heterojunction exhibits an enhanced HER rate of 34.66 mmol h−1 g−1 without an obvious decrease for continuous 24 h under visible irradiation, which is 4.8 times and 1.23 times than that of pristine Zn0.67Cd0.33S and uncapped Mo2C/Zn0.67Cd0.33S-5. This research highlights the role of Mo2C in photocatalytic HER, which provides a novel method to suppress the photo-corrosion of Zn0.67Cd0.33S-based composite.