High-Efficiency Ag-Modified ZnO/g-C₃N₄ Photocatalyst with 1D-0D-2D Morphology for Methylene Blue Degradation

Photocatalysts with different molar ratios of Ag-modified ZnO to g-C₃N₄ were prepared through an electrostatic self-assembly method and characterized through techniques such as X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. The resulting Ag-ZnO/g-C₃N₄ photocatalysts exhibited a unique 1D-0D-2D morphology and Z-type heterojunction. Moreover, g-C₃N₄ nanosheets with large layer spacing were prepared using acid treatment and thermal stripping methods. The Z-type heterostructure and localized surface plasmon resonance effect of Ag nanowires enabled high-speed electron transfer between the materials, while retaining large amounts of active substances, and broadened the light response range. Because of these features, the response current of the materials improved, and their impedance and photoluminescence reduced. Among the synthesized photocatalysts, 0.05Ag-ZnO/g-C₃N₄ (molar ratio of g-C₃N₄/ZnO: 0.05) exhibited the highest photocatalytic performance under UV–visible light. It degraded 98% of methylene blue in just 30 min, outperforming both g-C₃N₄ (21% degradation in 30 min) and Ag-ZnO (84% degradation in 30 min). In addition, 0.05Ag-ZnO/g-C₃N₄ demonstrated high cycling stability.