WO3/BiVO4 heterojunction has been developed as a promising photoelectrochemical(PEC) water splitting anode owing to their appropriate band edge positions and ability to absorb visible light. Although WO3 has moderate hole diffusion length and good electron transfer property within the material, WO3 alone as photoanode has limitations of poor charge separation and less utilization of solar irradiation. This limitation can be overcome by forming type 2 heterojunction with a small band gap material such as BiVO4. Here we report facile fabrication of nanostructured WO3/BVO heterojunction photoanodes by all-solution process. To fabricate this photoelectrodes in eco-friendly way, we synthesized WO3 by hydrothermal method without seed layer and BVO by pulsed electrodeposition. WO3 nanorods were synthesized uniformly on FTO substrate and BVO nanodots covered the entire WO3 surface. This electrode exhibits high current density which is double that of pristine WO3 nanorod arrays. Deposition of BVO lets the WO3 nanorods be well attached on the substrate and BVO acts as passivation layer on WO3 so that adhesion and stability can be enhanced. To further improve PEC properties and stability, we deposited additional catalyst on WO3/BVO. The catalyst effectively separates electron-hole pairs and reduces charge recombination. Consequently, the current density of this double heterojunction photoanode was increased and the onset potential shifted to negative compared to that of WO3/BVO and pristine WO3 electrode.

All-solution fabrication process of nanostructured WO3/BiVO4 heterojunction with catalyst for efficient solar water splitting

256th National Meeting (2018)

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