Boosting photoelectrochemical activity of bismuth vanadate by implanting oxygen-vacancy-rich cobalt (oxy)hydroxide

• Published in: Journal of colloid and interface science Vol. 611; pp. 278 - 286
• Main Authors: Sun, Huanhuan, Hua, Wei, Liang, Shiyu, Li, Yueying, Wang, Jian-Gan
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.04.2022
• Subjects: Bismuth vanadate; Cocatalyst; Oxygen vacancy; Photoelectrochemical water oxidation; Bismuth vanadate; Cocatalyst; Photoelectrochemical water oxidation; Oxygen vacancy
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2021.12.086

[Display omitted] •A self-transformation strategy is proposed to synthesize oxygen-vacancy-rich Co(O)OH cocatalyst.•The ultrathin Co(O)OH nanolayer facilitates charge transfer/separation and water oxidation kinetics.•The BiVO4/Co(O)OH hybrid photoanode exhibits a high photocurrent density of 4.2 mA cm−2.•The oxygen vacancies in Co(O)OH framework play a crucial role in improving the PEC activity. Surface charge recombination is regarded as a detrimental factor that severely downgrades the photoelectrochemical (PEC) performance of bismuth vanadate (BiVO4). In this work, we demonstrate defect-rich cobalt (oxy)hydroxides (Co(O)OH) as an excellent cocatalyst nanolayer sheathed on BiVO4 to substantially improve the PEC water oxidation activity. The self-transformation of metal–organic framework produces an ultrathin Co(O)OH layer rich in oxygen vacancies, which could serve as a powerful hole extraction engine to promote the charge transfer/separation efficiency as well as an excellent oxygen evolution reaction catalyst to accelerate the surface water oxidation kinetics. As a result, the BiVO4/Co(O)OH hybrid photoanode achieves remarkably inhibited surface charge recombination and presents a prominent photocurrent density of 4.2 mA cm−2 at 1.23 V vs. RHE, which is around 2.6-fold higher than that of the pristine BiVO4. Moreover, the Co(O)OH cocatalyst nanolayer significantly reduces the onset potential of BiVO4 photoanodes by 200 mV. This work provides a versatile strategy for rationally preparing oxygen-vacancy-rich cocatalysts on various photoanodes toward high-efficient PEC water oxidation.