Synergistic effect of Ag plasmon- and reduced graphene oxide-embedded ZnO nanorod-based photoanodes for enhanced photoelectrochemical activity

The influence of Ag plasmons and reduced graphene oxide (RGO) on ZnO nanorods (Z-NRs)-based photoanodes for photoelectrochemical splitting of water is the main focus of the present experimental study. Plasmonic layer of Ag is incorporated either as a base (Ag-Z-NRs) layer or as a top layer (Z-NRs-Ag) in an electrochemically deposited Z-NRs-based photoanodes. Z-NRs-Ag photoanodes exhibited better optical absorption as plasmonic layer stimulates charge transfer and restrain charge recombination. It had shown the photocurrent density of similar to 0.79 mA cm(-2), at a bias of 1.4 V/RHE. A mediator layer of RGO when introduced in Z-NRs-Ag photoanodes synergistically with Ag plasmons enhances the photocurrent density to similar to 1.3 mA cm(-2) at a bias of 1.4 V/RHE. Structure and surface morphology of the synthesized photoanodes was studied using x-ray diffraction and field emission scanning electron microscopy. Elemental analysis and optical characterization was done using energy-dispersive x-ray analysis, UV-Visible absorption spectroscopy and Raman spectroscopy. The current-voltage characteristics, electrochemical impedance spectroscopy, Mott-Schottky analysis, photoconversion efficiency and incident photon to current conversion efficiency measurements have been used to substantiate our observations of synthesized photoanodes.