Ag implanted ZnO hierarchical nanoflowers for photoelectrochemical water-splitting applications

Pristine ZnO and Ag-implanted ZnO hierarchical nanoflowers have been successfully synthesized via facile hydrothermal route for photoelectrochemical (PEC) water-splitting applications. The wurtzite hexagonal structural properties have been confirmed by X-ray diffraction (XRD), Raman, and Fourier transform infrared spectra analyses. As Ag content increases, the intensity of cation-sensitive plane (002) also increases, which has been pronounced by XRD result. The optical properties before and after Ag implantation have been thoroughly studied by photoluminescence and Ultraviolet–Visible diffuse reflectance spectroscopy spectra. The optimum concentration of 10% Ag-implanted ZnO possessed the minimum optical band gap of 3 eV. The visible particle size reduction with the increase of Ag concentration and also urchin like typical microflower morphology of synthesized nanostructures has been revealed by scanning electron microscopic images. The typical PEC behavior with 75.14 µA/cm² versus RHE has been observed in 10% Ag-implanted ZnO nanoflowers. Increase of Ag concentration enhances the electrocatalytic behavior of the photoanodes, which had been revealed in our study. Photostability over 3 h with 40% of retention has been reported in 10% Ag-implanted ZnO hierarchical nanoflower photoanodes. Hence, the optimum concentration of Ag implantation with ZnO could be adapted as an excellent photoanode for PEC water-splitting applications.