Surface Engineering of Cu 2 O Photocathodes via Facile Graphene Oxide Decoration for Improved Photoelectrochemical Water Splitting.

Copper oxide (Cu 2 O) has attracted significant interest as an efficient photocathode for photoelectrochemical (PEC) water splitting owing to its abundance, suitable band gap, and band-edge potential. Nevertheless, a high charge recombination rate restricts its practical photoconversion efficiency and reduces the PEC water-splitting performance. To address this challenge, we present the facile electrodeposition of graphene oxide (GO) on the Cu 2 O photocathode surface. To determine the effect of varying GO weight percentages on PEC performance, varying amounts of GO were deposited on the Cu 2 O photocathode surface. The optimally deposited GO-Cu 2 O photocathode exhibited a photocurrent density of -0.39 to -1.20 mA/cm 2 , which was three times that of a photocathode composed of pristine Cu 2 O. The surface decoration of Cu 2 O with GO reduced charge recombination and improved the PEC water-splitting performance. These composites can be utilized in strategies designed to address the challenges associated with low-efficiency Cu 2 O photocathodes. The physicochemical properties of the prepared samples were comprehensively characterized by field-emission scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, Raman spectroscopy, UV-visible spectroscopy, and X-ray photoelectron spectroscopy. We believe that this research will pave the way for developing efficient Cu 2 O-based photocathodes for PEC water splitting.