Photo and electrochemical applications of green synthesized ZnO/Ag2O nanocomposites materials under visible light using P. macrosolen L. leaf.

Abstract

This study investigates the photo-catalytic and super-capacitive properties of green-synthesized ZnO/Ag₂O nanocomposites using P. macrosolen L. leaf extract. The synthesis was performed in a single step at low temperature with a short reaction time. The synthesized materials were characterized using XRD, SEM, TEM, FTIR, UV-VIS and XPS. The ZnO/Ag₂O nanocomposites exhibited exceptional photo-catalytic efficiency and stability under visible light for the degradation of carbon-based dyes. The degradation rate constants of the optimized ZnO/Ag₂O nanocomposites were 0.054351 min⁻¹ for Methylene Orange (MO) and 0.048751 min⁻¹ for Toluidine Blue (TB), achieving degradation efficiencies of 99.69% and 98.50%, respectively, compared to ZnO (0.0075 min⁻¹). This remarkable improvement in visible-light photo-catalytic performance is attributed to the hetero-junction formation, which enhances charge separation and transfer through the matched crystal lattices and energy bands of Ag₂O and ZnO. The Ag₂O nanoparticles efficiently generate and transfer excited electrons to the ZnO conduction band under visible-light irradiation. Electrochemical studies revealed a significant improvement in specific capacitance, with the ZnO/Ag₂O composite containing 50 wt% AgNO₃ achieving a maximum specific capacitance of 655.0 F/g at a scan rate of 10 mV/s. This superior performance highlights the synergistic effect of ZnO and Ag₂O in improving photo-catalytic and electrochemical properties. These findings demonstrate the potential of ZnO/Ag₂O nanocomposites for industrial dye degradation and super-capacitor applications.