Cationic vacancy engineering of MnCdS for enhanced photocatalytic hydrogen evolution reaction rates

Abstract

The suboptimal photocatalytic hydrogen evolution activity of current MnCdS-based photocatalysts primarily stems from insufficient active sites and rapid recombination of photogenerated electron–hole pairs. Defect engineering offers a promising pathway to address these limitations. Therefore, in this study, MnCdS catalysts enriched with Mn defects were successfully prepared through the strategy of introducing metal cation vacancies. The optimized catalyst achieves an exceptional hydrogen evolution rate of 43.54 mmol g⁻¹ h⁻¹, which is three times higher than that of pristine MnCdS, while maintaining high stability. This significant enhancement is attributed to ethylenediamine (En)-induced Mn vacancies, which simultaneously augment active sites for electron capture in the conduction band and significantly accelerate water dissociation kinetics. By precisely regulating metal cation defects, this work demonstrates a highly efficient and stable photocatalyst while establishing a viable defect-engineering paradigm for advancing photocatalytic hydrogen evolution.