title: Particulate Photocatalyst Sheets Based on Carbon Conductor Layer for Efficient Z-Scheme Pure-Water Splitting at Ambient Pressure.
abstract: Development of sunlight-driven water splitting systems with high efficiency, scalability, and cost-competitiveness is a central issue for mass production of solar hydrogen as a renewable and storable energy carrier. Photocatalyst sheets comprising a particulate hydrogen evolution photocatalyst (HEP) and an oxygen evolution photocatalyst (OEP) embedded in a conductive thin film can realize efficient and scalable solar hydrogen production using Z-scheme water splitting. However, the use of expensive precious metal thin films that also promote reverse reactions is a major obstacle to developing a cost-effective process at ambient pressure. In this study, we present a standalone particulate photocatalyst sheet based on an earth-abundant, relatively inert, and conductive carbon film for efficient Z-scheme water splitting at ambient pressure. A SrTiO3:La,Rh/C/BiVO4:Mo sheet is shown to achieve unassisted pure-water (pH 6.8) splitting with a solar-to-hydrogen energy conversion efficiency (STH) of 1.2% at 331 K and 10 kPa, while retaining 80% of this efficiency at 91 kPa. The STH value of 1.0% is the highest among Z-scheme pure water splitting operating at ambient pressure. The working mechanism of the photocatalyst sheet is discussed on the basis of band diagram simulation. In addition, the photocatalyst sheet split pure water more efficiently than conventional powder suspension systems and photoelectrochemical parallel cells because H+and OH-concentration overpotentials and an IR drop between the HEP and OEP were effectively suppressed. The proposed carbon-based photocatalyst sheet, which can be used at ambient pressure, is an important alternative to (photo)electrochemical systems for practical solar hydrogen production.
authors.affiliation: Department of Chemical System Engineering, School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.|Japan Technological Research Association of Artificial Photosynthetic Chemical Process (ARPChem) , 2-11-9 Iwamotocho, Chiyoda-ku, Tokyo 101-0032, Japan.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Chemical System Engineering, School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.|Japan Technological Research Association of Artificial Photosynthetic Chemical Process (ARPChem) , 2-11-9 Iwamotocho, Chiyoda-ku, Tokyo 101-0032, Japan.
authors.forename: Takashi
authors.identifier: 0000-0002-5009-2383
authors.initials: T
authors.lastname: Hisatomi
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
authors.forename: Yohichi
authors.initials: Y
authors.lastname: Suzuki
authors.affiliation: Department of Chemical System Engineering, School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Pan
authors.affiliation: Department of Chemical System Engineering, School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.|Japan Technological Research Association of Artificial Photosynthetic Chemical Process (ARPChem) , 2-11-9 Iwamotocho, Chiyoda-ku, Tokyo 101-0032, Japan.
authors.forename: Jeongsuk
authors.initials: J
authors.lastname: Seo
authors.affiliation: Department of Chemical System Engineering, School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.|Japan Technological Research Association of Artificial Photosynthetic Chemical Process (ARPChem) , 2-11-9 Iwamotocho, Chiyoda-ku, Tokyo 101-0032, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Katayama
authors.affiliation: Department of Chemical System Engineering, School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.|Japan Technological Research Association of Artificial Photosynthetic Chemical Process (ARPChem) , 2-11-9 Iwamotocho, Chiyoda-ku, Tokyo 101-0032, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Minegishi
authors.affiliation: Department of Chemical System Engineering, School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.|Japan Technological Research Association of Artificial Photosynthetic Chemical Process (ARPChem) , 2-11-9 Iwamotocho, Chiyoda-ku, Tokyo 101-0032, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nishiyama
authors.affiliation: Department of Chemical System Engineering, School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.|Japan Technological Research Association of Artificial Photosynthetic Chemical Process (ARPChem) , 2-11-9 Iwamotocho, Chiyoda-ku, Tokyo 101-0032, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Takata
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Seki
authors.affiliation: Department of Applied Chemistry, Tokyo University of Science , 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kudo
authors.affiliation: Department of Chemical System Engineering, School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.|Japan Technological Research Association of Artificial Photosynthetic Chemical Process (ARPChem) , 2-11-9 Iwamotocho, Chiyoda-ku, Tokyo 101-0032, Japan.
authors.forename: Taro
authors.initials: T
authors.lastname: Yamada
authors.affiliation: Department of Chemical System Engineering, School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.|Japan Technological Research Association of Artificial Photosynthetic Chemical Process (ARPChem) , 2-11-9 Iwamotocho, Chiyoda-ku, Tokyo 101-0032, Japan.
authors.forename: Kazunari
authors.identifier: 0000-0001-7995-4832
authors.initials: K
authors.lastname: Domen