Preparation of Surface Dispersed WO 3 /BiVO 4 Heterojunction Arrays and Their Photoelectrochemical Performance for Water Splitting.

In this work, a surface dispersed heterojunction of BiVO 4 -nanoparticle@WO 3 -nanoflake was successfully prepared by hydrothermal combined with solvothermal method. We optimized the morphology of the WO 3 nanoflakes and BiVO 4 nanoparticles by controlling the synthesis conditions to get the uniform BiVO 4 loaded on the surface of WO 3 arrays. The phase composition and morphology evolution with different reaction precursors were investigated in detail. When used as photoanodes, the WO 3 /BiVO 4 composite exhibits superior activity with photocurrent at 3.53 mA cm -2 for photoelectrochemical (PEC) water oxidation, which is twice that of pure WO 3 photoanode. The superior surface dispersion structure of the BiVO 4 -nanoparticle@WO 3 -nanoflake heterojunction ensures a large effective heterojunction area and relieves the interfacial hole accumulation at the same time, which contributes to the improved photocurrents together with the stability of the WO 3 /BiVO 4 photoanodes.