Novel in Situ Synthesis of BiVO4 Photocatalyst/Co3(PO4)2 Co-Catalyst Powder via the One-Step Solid-State Process for Photoelectrochemical Catalyzing Water Oxidation

• Published in: ACS sustainable chemistry & engineering Vol. 8; no. 7; pp. 2948 - 2956
• Main Authors: Wu, Yu-Tzu, Lin, Lu-Yin, Tao, Shang-Mao, Chen, Yu-Shiang, Ma, Jia-Sheng, Lee, Pin-Yan, Sung, Yu-Shun
• Format: Journal Article
• Language: English
• Published: American Chemical Society 24.02.2020
• Subjects: solid-state synthesis; electrochemical impedance spectroscopy; water oxidation; bismuth vanadate; photocatalyst; co-catalyst
• ISSN: 2168-0485; 2168-0485
• DOI: 10.1021/acssuschemeng.9b07517

Bismuth vanadate (BiVO4) is one of the promising photocatalysts for water oxidation owing to suitable band positions and the visible light-responsive band gap, but the short charge diffusion path limits application. Coupling co-catalysts with BiVO4 is widely applied for increasing charge diffusion path by creating efficient charge-transfer routes. In this study, it is the first time to in situ-synthesize BiVO4 coupled with the Co3(PO4)2 co-catalyst using the one-step solid-state process, which is easier and less toxic than wet route synthesis with extra solvent participation. The W and Mo co-doped BiVO4 is fabricated and coupled with the Co3(PO4)2 co-catalyst directly using the solid-state process. A highest photocurrent density of 0.30 mA/cm2 at 1.23 VRHE is obtained for the BiVO4/Co3(PO4)2 electrode, while the BiVO4 electrode only shows a photocurrent density of 0.13 mA/cm2 at 1.23 VRHE owing to smaller charge-transfer resistance and larger carrier density for the BiVO4/Co3(PO4)2 electrode with co-catalyst incorporation, as investigated by using electrochemical impedance spectroscopy. The successful incorporation of the co-catalyst in BiVO4 using the novel solid-state process provides a brand-new blueprint for constructing photocatalyst/co-catalyst systems. Other effective co-catalysts are expected to effectively couple with BiVO4 using this solid-state method, and more efficient catalyst systems for water oxidation are expected to develop in the future.