Charge Transport Enhancement in BiVO4 Photoanode for Efficient Solar Water Oxidation

• Published in: Materials 2023-04, Vol.16 (9), p.3414
• Main Authors: Li, Zhidong, Xie, Zhibin, Li, Weibang, Aziz, Hafiz Sartaj, Abbas, Muhammad, Zheng, Zhuanghao, Su, Zhenghua, Fan, Ping, Chen, Shuo, Liang, Guangxing
• Format: Article
• Language: English
• Subjects: Annealing; Bismuth oxides; Charge transport; Current efficiency; Density; Electrodes; Electrolytes; Glass substrates; Grain size; Hydrogen; Hydrogen evolution; Kinetics; Oxidation; Photoanodes; Photoelectric effect; Photoelectric emission; Quantum dots; Scanning electron microscopy; Spectrum analysis; Vanadates; Water splitting
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma16093414

Photoelectrochemical (PEC) water splitting in a pH-neutral electrolyte has attracted more and more attention in the field of sustainable energy. Bismuth vanadate (BiVO4) is a highly promising photoanode material for PEC water splitting. Additionally, cobaltous phosphate (CoPi) is a material that can be synthesized from Earth’s rich materials and operates stably in pH-neutral conditions. Herein, we propose a strategy to enhance the charge transport ability and improve PEC performance by electrodepositing the in situ synthesis of a CoPi layer on the BiVO4. With the CoPi co-catalyst, the water oxidation reaction can be accelerated and charge recombination centers are effectively passivated on BiVO4. The BiVO4/CoPi photoanode shows a significantly enhanced photocurrent density (Jph) and applied bias photon-to-current efficiency (ABPE), which are 1.8 and 3.2 times higher than those of a single BiVO4 layer, respectively. Finally, the FTO/BiVO4/CoPi photoanode displays a photocurrent density of 1.39 mA cm−2 at 1.23 VRHE, an onset potential (Von) of 0.30 VRHE, and an ABPE of 0.45%, paving a potential path for future hydrogen evolution by solar-driven water splitting.