title: Ultrafast fabrication of highly active BiVO4photoanodes by hybrid microwave annealing for unbiased solar water splitting.
abstract: Hybrid microwave annealing (HMA) with a silicon susceptor in a household microwave oven produces BiVO4-based photoanodes of much improved performance in photoelectrochemical water oxidation in only 6 min relative to conventional thermal annealing in a traditional muffle furnace (FA) that needs a much longer time, 300 min. This technique can apply equally effectively to bare as well as modified BiVO4by Mo-doping, heterojunction formation with WO3, and an oxygen evolution co-catalyst. Relative to FA, HMA forms BiVO4films of smaller feature sizes, higher porosity, and increased three dimensional roughness, which decrease the diffusion distance of holes to the surface and thereby increase mainly the bulk charge separation efficiency (ηbulk) of the photoanodes. Thus, the HMA-treated BiVO4/WO3film achieves the state-of-the art ηbulkof ∼90% for water oxidation. Combination of a photoanode of NiOOH/FeOOH/BiVO4/WO3(HMA, 6 min) with a 2p c-Si solar cell allows a solar to hydrogen conversion efficiency of ∼5.0% in unbiased overall water splitting, which is also comparable to the state-of-the-art for a similar material combination.
authors.affiliation: School of Environmental Science & Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 790-784 South Korea.
authors.forename: Jin Hyun
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Advanced Center for Energy, Korea Institute of Energy Research (KIER), Ulsan, 689-798 South Korea.
authors.forename: Yim Hyun
authors.initials: YH
authors.lastname: Jo
authors.affiliation: School of Energy and Chemical Engineering, National Institute of Science and Technology (UNIST), Ulsan, 689-798, South Korea. jlee1234@unist.ac.kr.
authors.forename: Ju Hun
authors.initials: JH
authors.lastname: Kim
authors.affiliation: School of Energy and Chemical Engineering, National Institute of Science and Technology (UNIST), Ulsan, 689-798, South Korea. jlee1234@unist.ac.kr.
authors.forename: Jae Sung
authors.initials: JS
authors.lastname: Lee