Oxygen vacancies have been treated as an important material engineering tool to enhance catalytic performance; for instance, oxygen vacancies suppress charge recombination at the Schottky interface, and thus, the photocurrent can be improved. In this regard, the gradient distribution of oxygen vacancies in n-type metal oxides produces the ideal band structure for minimizing e−/h+ recombination by efficient hole extraction; however, its achievement remains a daunting challenge. Here, a photoelectrochemical (PEC)-driven “self-purification” process is suggested, which can effectively generate a gradient distribution of oxygen vacancies in the thickness range of ≈9.5 nm. As a result, a charge transport efficiency of >95% can be achieved by efficient hole migration from the photoanode to the electrolyte. This unique protocol is expected to provide an advanced metal oxide photocatalyst and photoelectrochemical electrode that exhibit superior photocatalytic performance with enhanced charge separation.
Bibliographical noteFunding Information:
K.H.K. and C.‐W.C. contributed equally to this work. J.H.P. acknowledges support from NRF Korea (2019R1A2C3010479, 2019M1A2A2065612) and Yonsei‐KIST Convergence Research Program. C.‐W.C. and S.‐Y.C. acknowledge the support of the Global Frontier Hybrid Interface Materials of the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (2013M3A6B1078872), and a Korea Basic Science Institute (National Research Facilities and Equipment Center) grant funded by the Ministry of Education (2020R1A6C101A202). K.‐S.L. acknowledges support from NRF Korea (2018M1A2A2061998).
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All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)