Rapid Synthesis of Ultrathin Ni:FeOOH with In Situ-Induced Oxygen Vacancies for Enhanced Water Oxidation Activity and Stability of BiVO4 Photoanodes

Mayur A Gaikwad; Uma V Ghorpade; Umesh P Suryawanshi; Priyank V Kumar; Suyoung Jang; Jun Sung Jang; Lan Tran; Jong-Sook Lee; Hyojung Bae; Seung Wook Shin; Mahesh P Suryawanshi; Jin Hyeok Kim

doi:10.1021/acsami.3c01877

Rapid Synthesis of Ultrathin Ni:FeOOH with In Situ-Induced Oxygen Vacancies for Enhanced Water Oxidation Activity and Stability of BiVO₄ Photoanodes

ACS Appl Mater Interfaces. 2023 May 3;15(17):21123-21133. doi: 10.1021/acsami.3c01877. Epub 2023 Apr 21.

Authors

Affiliations

¹ Optoelectronics Convergence Research Center and Department of Materials Science and Engineering, Chonnam National University, 300, Yongbong-Dong, Buk-Gu, Gwangju 61186, South Korea.
² School of Chemical Engineering and School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia.
³ School of Chemical Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia.
⁴ Department of Materials Science and Engineering, Chonnam National University, 300, Yongbong-Dong, Buk-Gu, Gwangju 61186, South Korea.
⁵ Optoelectronics Convergence Research Center and School of Chemical Engineering, Chonnam National University, Buk-gu, Gwangju 61186, South Korea.
⁶ Future Agricultural Research Division, Rural Research Institute, Korea Rural Community Corporation, Naju-Si 58327, Jeonranam-do, South Korea.
⁷ School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia.

PMID: 37083398
DOI: 10.1021/acsami.3c01877

Abstract

The coupling of oxygen evolution reaction (OER) catalysts with photoanodes is a promising strategy for enhancing the photoelectrochemical (PEC) performance by passivating photoanode's surface defect states and facilitating charge transfer at the photoanode/electrolyte interface. However, a serious interface recombination issue caused by poor interface and OER catalysts coating quality often limits further performance improvement of photoanodes. Herein, a rapid Fenton-like reaction method is demonstrated to produce ultrathin amorphous Ni:FeOOH catalysts with in situ-induced oxygen vacancies (Vo) to improve the water oxidation activity and stability of BiVO₄ photoanodes. The combined physical characterizations, PEC studies, and density functional theory calculations revealed that the reductive environment in a Fenton-like reaction in situ produces abundant Vo in Ni:FeOOH catalysts, which significantly improves charge separation and charge transfer efficiency of BiVO₄ while also offering abundant active sites and a reduced energy barrier for OER. As a result, Ni:FeOOH-Vo catalysts yielded a more than 2-fold increased photocurrent density in the BiVO₄ photoanode (from 1.54 to 4.15 mA cm^-2 at 1.23 V_RHE), accompanied by high stability for 5 h. This work not only highlights the significance of abundant Vo in catalysts but also provides new insights into the rational design and fabrication of efficient and stable solar water-splitting systems.

Keywords: BiVO4; Fenton-like reaction; in situ-induced oxygen vacancy; photoelectrochemical water oxidation; ultrathin Ni:FeOOH.