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

Huanhuan Sun; Wei Hua; Shiyu Liang; Yueying Li; Jian-Gan Wang

doi:10.1016/j.jcis.2021.12.086

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

J Colloid Interface Sci. 2022 Apr:611:278-286. doi: 10.1016/j.jcis.2021.12.086. Epub 2021 Dec 18.

Authors

Huanhuan Sun¹, Wei Hua¹, Shiyu Liang¹, Yueying Li², Jian-Gan Wang³

Affiliations

¹ State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Lab of Graphene (NPU), No. 127, Youyi West Road, Xi'an 710072, China.
² New Energy (Photovoltaic) Industry Research Center, Qinghai University, No. 251, Daning Road, Xining 810016, China.
³ State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Lab of Graphene (NPU), No. 127, Youyi West Road, Xi'an 710072, China. Electronic address: wangjiangan@nwpu.edu.cn.

PMID: 34953460
DOI: 10.1016/j.jcis.2021.12.086

Abstract

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.

Keywords: Bismuth vanadate; Cocatalyst; Oxygen vacancy; Photoelectrochemical water oxidation.