Strategic Core-Shell Integration for Advancing Z-Scheme Heterojunctions: Interface-Engineered ZnIn₂S₄/Ag₂WO₄@Ag Ternary Architecture for Enhanced Visible-Light-Driven Photocatalytic H₂ Production and Pollutant Degradation

The spatial inhomogeneity of interfacial modifications, despite conventional approaches like co-catalyst deposition and dopant incorporation, presents a critical bottleneck in achieving optimal charge carrier dynamics and sustained photocatalytic performance at semiconductor heterojunctions. To address this challenge, this study introduces a novel approach by encapsulating the wide-bandgap semiconductor Ag₂WO₄ (AWO) in a particulate shell of plasmonic hot spots (metallic Ag), forming a well-defined interface that facilitates consistent charge transfer and enhances photocatalytic efficiency. The engineered Ag₂WO₄@Ag (AWO@Ag) is strategically integrated with ZnIn₂S₄ (ZIS) nanosheets to design core–shell integrated Z-scheme heterojunction. The optimized integration of AWO@Ag (12.5%) over ZIS nanosheets demonstrates a remarkable hydrogen generation performance, achieving 3142 µmol h⁻¹g⁻¹, surpassing the performance of pure ZnIn₂S₄ (1311 µmol h⁻¹g⁻¹). Through rational interface design with strong redox abilities, the system achieves an impressive methyl orange photodegradation efficiency of 97.16% within 60 min. Additionally, it exhibits photoanodic currents of 3.98 mA cm⁻² at 2.2 V versus RHE in a neutral electrolytic medium, demonstrating enhanced water oxidation capability facilitated by AWO@Ag integration. The system's exceptional performance across hydrogen generation, dye degradation, and water oxidation, validates that this advanced structural design enables stable and sustained photocatalytic performance through its multifunctional properties.