Constructing a sulfure‑vacancy enriched Schottky heterojunction in Ni‑CdZnS/Ti3C2Tx for efficient photocatalytic hydrogen evolution under visible light

Photocatalytic hydrogen evolution represents a crucial pathway for sustainable energy conversion, where constructing efficient heterojunctions and employing strategic doping are key to enhancing performance. Herein, a Ni-doped CdZnS/Ti 3 C 2 T x Schottky heterojunction was constructed via a hydrothermal method to enhance photocatalytic hydrogen evolution. Ni doping introduces sulfur vacancies that improve charge conductivity, while coupling with Ti 3 C 2 T x MXene forms a Schottky junction that directs interfacial electron transfer and suppresses recombination. Density functional theory (DFT) calculations confirm that sulfur vacancies and the Schottky barrier act synergistically to optimize charge dynamics, and that Ti 3 C 2 T x shifts the d-band center of Ni toward the Fermi level of the sample, promoting hydrogen desorption process. The optimized Ni-CdZnS/Ti 3 C 2 T x composite exhibits a high visible-light driven hydrogen evolution rate of 13.67 mmol g −1 h −1 — 3.73-folds that of pristine CdZnS — along with an apparent quantum efficiency (AQY) of 20.15% at 365 nm, while maintaining favorable stability. This work demonstrates an effective strategy integrating defect engineering and Schottky junction design for efficient solar hydrogen evolution.