Suppressing photoinduced charge recombination at the BiVO4||NiOOH junction by sandwiching an oxygen vacancy layer for efficient photoelectrochemical water oxidation

• Published in: Journal of colloid and interface science 2022-02, Vol.608, p.1116-1125
• Main Authors: Peng, Yong, Du, Minshu, Zou, Xingli, Jia, Guohua, Permatasari Santoso, Shella, Peng, Xiang, Niu, Wenxin, Yuan, Mingjian, Hsu, Hsien-Yi
• Format: Article
• Language: English
• Subjects: Nickel oxyhydroxide; Oxygen vacancies; Photoelectrochemistry; Surface engineering
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2021.10.063

[Display omitted] Nickel oxyhydroxide (NiOOH) is regarded as one of the promising cocatalysts to enhance the catalytic performance of photoanodes but suffers from serious interfacial charge-carrier recombination at the photoanode||NiOOH interface. In this work, surface-engineered BiVO4 photoanodes are fabricated by sandwiching an oxygen vacancy (Ovac) interlayer between BiVO4 and NiOOH. The surface Ovac interlayer is introduced on BiVO4 by a chemical reduction treatment using a mild reducing agent, sodium hypophosphite. The induced Ovac can alleviate the interfacial charge-carrier recombination at the BiVO4||NiOOH junction, resulting in efficient charge separation and transfer efficiencies, while an outer NiOOH layer is coated to prevent the Ovac layer from degradation. As a result, the as-prepared NiOOH-P-BiVO4 photoanode exhibits a high photocurrent density of 3.2 mA cm−2 at 1.23 V vs. RHE under the irradiation of 100 mW/cm2 AM 1.5G simulated sunlight, in comparison to those of bare BiVO4, P-BiVO4, and NiOOH-BiVO4 photoanodes (1.1, 2.1 and 2.3 mA cm−2, respectively). In addition to the superior photoactivity, the 5-h amperometric measurements illustrate improved stability of the surface-engineered NiOOH-P-BiVO4 photoanode. Our work showcases the feasibility of combining cocatalysts with Ovac, for improved photoactivity and stability of photoelectrodes.