Photocatalytic generation of hydrogen by core-shell WO3/BiVO4 nanorods with ultimate water splitting efficiency

Yuriy Pihosh, Ivan Turkevych, Kazuma Mawatari, Jin Uemura, Yutaka Kazoe, Sonya Kosar, Kikuo Makita, Takeyoshi Sugaya, Takuya Matsui, Daisuke Fujita, Masahiro Tosa, Michio Kondo, Takehiko Kitamori

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252 Citations (Scopus)

Abstract

Efficient photocatalytic water splitting requires effective generation, separation and transfer of photo-induced charge carriers that can hardly be achieved simultaneously in a single material. Here we show that the effectiveness of each process can be separately maximized in a nanostructured heterojunction with extremely thin absorber layer. We demonstrate this concept on WO 3 /BiVO 4 +CoPi core-shell nanostructured photoanode that achieves near theoretical water splitting efficiency. BiVO 4 is characterized by a high recombination rate of photogenerated carriers that have much shorter diffusion length than the thickness required for sufficient light absorption. This issue can be resolved by the combination of BiVO 4 with more conductive WO 3 nanorods in a form of core-shell heterojunction, where the BiVO 4 absorber layer is thinner than the carrier diffusion length while it's optical thickness is reestablished by light trapping in high aspect ratio nanostructures. Our photoanode demonstrates ultimate water splitting photocurrent of 6.72mAcm -2 under 1 sun illumination at 1.23V RHE that corresponds to ∼90% of the theoretically possible value for BiVO 4. We also demonstrate a self-biased operation of the photoanode in tandem with a double-junction GaAs/InGaAsP photovoltaic cell with stable water splitting photocurrent of 6.56mAcm -2 that corresponds to the solar to hydrogen generation efficiency of 8.1%.

Original languageEnglish
Article number11141
JournalScientific reports
Volume5
DOIs
Publication statusPublished - 2015 Jun 8
Externally publishedYes

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    Pihosh, Y., Turkevych, I., Mawatari, K., Uemura, J., Kazoe, Y., Kosar, S., Makita, K., Sugaya, T., Matsui, T., Fujita, D., Tosa, M., Kondo, M., & Kitamori, T. (2015). Photocatalytic generation of hydrogen by core-shell WO3/BiVO4 nanorods with ultimate water splitting efficiency. Scientific reports, 5, [11141]. https://doi.org/10.1038/srep11141