Impact of Varying the Photoanode/Catalyst Interfacial Composition on Solar Water Oxidation: The Case of BiVO4(010)/FeOOH Photoanodes
- Univ. of Wisconsin, Madison, WI (United States)
- Univ. of Chicago, IL (United States)
- Brookhaven National Laboratory (BNL), Upton, NY (United States). Center for Functional Nanomaterials (CFN)
- Brookhaven National Laboratory (BNL), Upton, NY (United States). Center for Functional Nanomaterials (CFN); Stony Brook Univ., NY (United States)
- Univ. of Chicago, IL (United States); Argonne National Laboratory (ANL), Argonne, IL (United States)
Photoanodes used in a water-splitting photoelectrochemical cell are almost always paired with an oxygen evolution catalyst (OEC) to efficiently utilize photon-generated holes for water oxidation because the surfaces of photoanodes are typically not catalytic for the water oxidation reaction. Suppressing electron–hole recombination at the photoanode/OEC interface is critical for the OEC to maximally utilize the holes reaching the interface for water oxidation. Here, in order to explicitly demonstrate and investigate how the detailed features of the photoanode/OEC interface affect interfacial charge transfer and photocurrent generation for water oxidation, we prepared two BiVO4(010)/FeOOH photoanodes with different Bi:V ratios at the outermost layer of the BiVO4 interface (close to stoichiometric vs Bi-rich) while keeping all other factors in the bulk BiVO4 and FeOOH layers identical. The resulting two photoanodes show striking differences in the photocurrent onset potential and photocurrent density for water oxidation. The ambient pressure X-ray photoelectron spectroscopy results show that these two BiVO4(010)/FeOOH photoanodes show drastically different Fe2+:Fe3+ ratios in FeOOH both in the dark and under illumination with water, demonstrating the immense impact of the interfacial composition and structure on interfacial charge transfer. Using computational studies, we reveal the effect of the surface Bi:V ratio on the hydration of the BiVO4 surface and bonding with the FeOOH layer, which in turn affect the band alignments between BiVO4 and FeOOH. These results explain the atomic origin of the experimentally observed differences in electron and hole transfer and solar water oxidation performance of the two photoanodes having different interfacial compositions.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY (United States). Center for Functional Nanomaterials (CFN)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF); National Science Foundation (NSF)
- Grant/Contract Number:
- SC0012704; CHE-2054986
- OSTI ID:
- 2229631
- Report Number(s):
- BNL-225057-2023-JAAM
- Journal Information:
- Journal of the American Chemical Society, Vol. 145, Issue 43; ISSN 0002-7863
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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