Cactus shaped FeOOH/Au/BiVO4 photoanodes for efficient photoelectrochemical water splitting

In this work, a FeOOH/Au/BiVO4 photoanode was fabricated through dual modification with Au nanoparticles (NPs, similar to 5 nm) and FeOOH nanoneedles (NNs) on nanoporous BiVO4 surface. Both the Au NPs and FeOOH NNs were distributed uniformly onto the BiVO4 by using the electrodeposition and chemisorption routes, respectively. After parameter optimization, the FeOOH/Au/BiVO4 photoanode displayed a photocurrent density of 4.64 mA cm(-2) at 1.23 VRHE, which was 3.74 times higher than the pristine BiVO4 one. Besides, the FeOOH/Au/BiVO4 photoanodes also displayed a maximum H-2 yield amount of 23.9 mmol cm(-2) h(-1). The significantly enhanced performance could be attributed to the following reasons: Introduction of Au NPs enhanced the visible light absorption through localized surface plasmon resonance (LSPR) effect; the photo-excited hot electrons of Au NPs were more likely to flow into the conduction band (CB) of BiVO4 via a direct electron transfer mechanism, leading to an improvement of the charge separation/transfer efficiency; surface modification of FeOOH extracted photogenerated holes, leading to an acceleration of the surface catalytic kinetics. In a word, the present study suggests that cosensitization of Au NPs and FeOOH might be an effective method for improving the PEC water oxidation kinetics of BiVO4 photoanodes. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

By dual modification with Au nanoparticles and FeOOH nanoneedles on BiVO4 surface, the FeOOH/Au/BiVO4 photoanode exhibited significantly enhanced performance, with a 3.74 times increase in photocurrent density and a significant increase in H-2 yield. The improved performance can be attributed to the localized surface plasmon resonance effect of Au NPs and surface modification of FeOOH.