Enhanced performance of photoelectrochemical water oxidation using a three-dimensional interconnected nanostructural photoanode via simultaneously harnessing charge transfer and coating with an oxygen evolution catalyst

The most important factors dominating photoelectrochemical (PEC) water splitting performance include light absorption, charge separation and transport, and surface chemical reactions. In order to meet these factors, a novel FexNi1-xO/Bi2MoO6/Si nanowire hierarchical nanostructure was produced using a metal-assisted chemical-etching and hydrothermal growth process, in which Si nanowires were used as backbones, Bi2MoO6 nanosheets as coating, and FexNi1-xO nanoparticles (NPs) as surface catalysts. This integrated three-dimensional (3D) hierarchical nanostructure was applied as a photoanode in a PEC water reaction, and higher photostability and photocurrent density were gained. The excellent PEC performance was due to the 3D hierarchically structural effect, resulting in the enhancement of the surface-to-volume ratio, light harvest and high speed electron transport, and at the same time, terminal FexNi1-xO NPs played the role of the surface catalyst effectively in order to accelerate the water splitting reaction and enhance photostability. Based on such an environmentally friendly hierarchical nanostructure, the study provided an efficient route to improve water-splitting performance and it could also be a model structure for similar electrode materials. (C) 2016 Elsevier Ltd. All rights reserved.