Engineering Cu₂O Nanowire Surfaces for Photoelectrochemical Hydrogen Evolution Reaction

High Resolution Image Download MS PowerPoint Slide Cu 2 O is a narrow band gap material serving as an important candidate for photoelectrochemical hydrogen evolution reaction. However, the main challenge that hinders its practical exploitation is its poor photostability, due to its oxidation into CuO by photoexcited holes. Here, we thoroughly minimize the photo-oxidation of Cu 2 O nanowires by growing a thin layer of the TiO 2 protective layer and an amorphous layer of the VO x cocatalyst using magnetron sputtering and atomic layer deposition, respectively. After optimization of the protective and the cocatalyst layers, the photoelectrode exhibits a current density of −2.46 mA/cm 2 under simulated sunlight (100 mW/cm 2 ) at 0.3 V versus reversible hydrogen electrode, and its performance is stable for an extended illumination time. The chemical stability and the good performance of the engineered photoelectrode demonstrate the potential of using earth-abundant materials as a light-harvesting device for solar hydrogen production.