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 ~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 ~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.