Oxygen network formation for efficient charge transport and durable BiVO4 photoanodes with ultra-thin TiO2 layer in solar water splitting
Bismuth vanadate (BiVO4) has emerged as a prominent oxide semiconductor in solar water splitting investigations owing to facile synthesis and favorable band-alignment with the water oxidation level. Oxygen and oxygen vacancies (VO) within the BiVO4 exhibit multifaceted roles across bulk, surface, an...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-06-01
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| Series: | Applied Surface Science Advances |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2666523925000455 |
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| Summary: | Bismuth vanadate (BiVO4) has emerged as a prominent oxide semiconductor in solar water splitting investigations owing to facile synthesis and favorable band-alignment with the water oxidation level. Oxygen and oxygen vacancies (VO) within the BiVO4 exhibit multifaceted roles across bulk, surface, and interface. This study presents a method for selectively regulating the surface and bulk VO in BiVO4 through facile chemical redox reactions. A large amount of VO on the BiVO4 surface enables the formation of a robust networking interface with oxide-based protection overlayers, whereas VO in bulk region must be effectively suppressed. A significant amount of VO can be specifically formed on the BiVO4 surface via a controlled surface chemical reduction reaction (SCR) at the atomic level, precisely controlling the presence of O2- and OH- ions. Here, we quantitatively and qualitatively analyze VO changes and the impact of VO on photoelectrochemical operation. As a result, The SCR process allows for the strategic control of the BiVO4 surface into a VO-rich surface. The controlled surface enhances the charge kinetic by promoting the conformal coating of a n-TiO2 protective layer and decreasing the charge loss in the interface junction with ensuring stability. Furthermore, the SCR-BiVO4/TiO2/CoPi photoanodes exhibit a highly stable photocurrent density of 3.9 mA cm−2 at 1.23 VRHE. Surface modification and understanding of the oxygen-end network can be broadly applied to photoelectrodes that require oxide-based overlays. |
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| ISSN: | 2666-5239 |