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

Abstract

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.