FeOOH/rGO/BiVO4 Photoanode for Highly Enhanced Photoelectrochemical Water Splitting Performance

Graphical PEC water splitting : A novel FeOOH/rGO/BiVO 4 photoanode was prepared for the first time with excellent PEC performance in which rGO as a hole-transporting layer significantly enhanced carrier separation efficiencies and FeOOH greatly accelerated the water oxidation kinetics. Bismuth vanadate (BiVO 4 ) is regarded as a potential material in photoelectrochemical (PEC) water splitting, but the photocurrent of BiVO 4 photoanode is much lower than its theoretical value for the high recombination of photo-induced charges and slow water oxidation kinetics. Here, we constructed a FeOOH/rGO/BiVO 4 photoanode, in which rGO could enhance the photogenerated electron-hole separation efficiency by transporting holes and the FeOOH could greatly accelerate the water oxidation kinetics. This novel photoanode displayed excellent PEC performance with the photocurrent density of 3.25 mA cm −2 at 1.23 V vs. RHE, 3.28 times higher than BiVO 4 photoanode (0.99 mA cm −2 ), and long-term stability with the Faraday efficiency of ∼98 % for 3 hours, demonstrating its great potential for PEC water splitting. The photoanode also provided a novel insight into the role of rGO to transport holes rather than electrons in improving the carrier separation efficiency.