SYNTHESIS AND CHARACTERIZATIONS OF Ag DOPPED ZnO NANOSTRUCTURES FOR ELECTROCATALYST AND ADVANCED ELECTRODE MATERIALS FOR ENERGY STORAGE APPLICATIONS

Abstract

In this work ZnO, and Ag-dopped ZnO (Ag-ZnO) nanostructures were successfully synthesized via facile hydrothermal method and systematically investigated for photocatalytic, electrocatalytic and energy storage applications. X-ray diffraction (XRD) confirmed the crystalline nature for ZnO and Ag-ZnO with no impurity phases, indicating successful incorporation of Ag in the ZnO. Scanning electron microscopy (SEM) revealed a nanowire morphology for pristine ZnO, while Ag-ZnO exhibited nanowires decorated on nanorods demonstrating significant morphological modification due to Ag doping. Energy disperse X-ray spectroscopy (EDS) verified the elemental composition and confirmed the presence of Zn, O in the ZnO, while Zn, O and Ag in the Ag-ZnO. Photocatalytic degradation studies demonstrated that Ag-ZnO exhibits superior photocatalytic performance compare to pristine ZnO, attributed to enhanced charge separation and improve light absorption. Linear sweep voltammetry (LSV) analysis revealed that 3% Ag-ZnO have over potential of 183 V and Tafel slope of 48 mVdec^-1 for hydrogen evolution reaction (HER) and overpotential of 180 V and Tafel slope of 52.43 mVdec^-1 oxygen evolution reaction (OER). Further electrochemical studied show highest specific capacitance of 388.4 F/g at 20 mVs^-1 for 3% Ag-ZnO from Cyclic voltammetry curve (CV). Electrochemical impedance spectroscopy (EIS) showed lowest charge transfer resistance of 93 Ω, for 3% Ag-ZnO. Galvanostatic charge discharge (GCD) showed highest specific capacitance of 400 F/g at 1 A/g, energy density of 35.55 Wh/kg at 1 A/g and power density of 1688 W/kg at 5 A/g. These results highlight Ag-ZnO as a promising multifunctional material for electrocatalyst and advanced energy storage applications.