Air-condition process for scalable fabrication of CdS/ZnS 1D/2D heterojunctions toward efficient and stable photocatalytic hydrogen production

We report the scalable fabrication of CdS/ZnS 1D/2D heterojunctions under ambient air conditions (i.e., room temperature and atmospheric pressure) in which ZnS nanoparticles are anchored on the surface of CdS nanosheets. The as-formed heterojunctions exhibit a significantly enhanced photocatalytic H₂ evolution rate of 14.02 mmol h⁻¹ g⁻¹ when irradiated with visible light, which is ~10 and 85 times higher than those of pristine CdS nanosheets and CdS nanoparticles, respectively, and superior to most of the CdS-based photocatalysts reported to date. Furthermore, they provide robust photocatalytic performance with demonstratable stability over 58 h, indicating their potential for practical applications. The formation of 1D/2D heterojunctions not only provides improved exposed active sites that respond to illumination but also provides a rapid pathway to generate photogenerated carriers for efficient separation and transfer through the matrix of single-crystalline CdS nanosheets. In addition, first-principles simulations demonstrate that the existence of rich Zn vacancies increases the energy level of the ZnS valence band maximum to construct type-II and Z-scheme mixed heterojunctions, which plays a critical role in suppressing the recombination of carriers with limited photocorrosion of CdS to enhance photocatalytic behavior.