Synergistic effect of type-II heterojunction and cocatalyst loading on BiVO4-based photoanode for enhanced photoelectrochemical water splitting H2 evolution

The combination of band structure and cocatalyst loading can greatly improve photoelectrochemical (PEC) water splitting H 2 generation of the semiconductor photoanodes. This work reports the design and construction of a novel ternary BiVO 4 /FeVO 4 /FeOOH nanoporous film (NPF) photoanode based on BiVO 4 NPF modified with FeVO 4 nanoparticles (NPs) and FeOOH nanoneedles (NNs). As revealed by UV–vis absorption spectra, the BiVO 4 /FeVO 4 /FeOOH NPF photoanode displays good light-harvesting efficiency in the range of 300–800 nm. Electrochemical measurements and photoluminescence spectroscopy further demonstrate that the modification of FeVO 4 NPs and FeOOH NNs significantly enhances both the bulk charge separation efficiency and surface charge injection efficiency of the BiVO 4 NPF photoanode due to the Type-II band alignment established at the interface between BiVO 4 and FeVO 4 as well as cocatalyst action of FeOOH. The BiVO 4 /FeVO 4 /FeOOH NPF exhibits significantly enhanced PEC water splitting performance and achieves a H 2 evolution rate of 40.3 μmol cm −2  h −1 , which is 2.25 times and 13 times higher than that of BiVO 4 /FeVO 4 and pure BiVO 4 NPF photoanodes, respectively. This work presents a viable strategy for efficient PEC water splitting by synergistically optimizing band structure and cocatalysts.