Synergistic Cu/Ni doping and sulfur vacancy engineering in Cd0.9Zn0.1S derived from Prussian blue for efficient photo-Fenton degradation of tetracycline coupled with H2 and H2O2 production

Driven by the dual demands of global energy structure transformation and carbon neutrality goals, solar-driven green hydrogen and green chemical synthesis have become a focus. This study employs a Prussian blue template to guide the one-step synthesis of Cu/Ni co-doped Cd 0.9 Zn 0.1 S, which not only retains a high-surface-area porous framework with exposed active sites but also intentionally introduces abundant sulfur vacancies (Vs). The synergistic interplay of Cu doping (acting as electron-rich centers), Ni doping (serving as hole-trapping centers), and the generated V s collectively optimizes the band structure, extends light absorption to nearly 700 nm, and significantly enhances charge carrier separation. The optimized 10Cu/10Ni- Cd 0.9 Zn 0.1 S photocatalyst achieves an exceptional hydrogen production rate of 21.25 mmol g −1  h −1 (20-fold enhancement) and a H 2 O 2 production rate of 4.6 mmol g −1  h −1 under oxygen conditions (15-fold enhancement). Remarkably, the in-situ generated H 2 O 2 is efficiently activated on Cu/Ni sites and Vs via a photo-Fenton-like process, enabling rapid tetracycline degradation (94% within 40 min). DFT calculations reveal that the hydrogen adsorption free energy is optimized to −0.09 eV, and the introduced sulfur vacancies further lower the work function, promoting O 2 activation and charge transfer for both H 2 evolution and Fenton-like reactions. This study offers new insights into designing highly efficient photocatalysts by employing a coupled doping and vacancy engineering strategy to synergistically regulate redox-active sites, combining porous framework design for optimized mass transport and multifunctional environmental remediation.