title: Sunlight-driven hydrogen peroxide production from water and molecular oxygen by metal-free photocatalysts.
abstract: Design of green, safe, and sustainable process for the synthesis of hydrogen peroxide (H2 O2 ) is a very important subject. Early reported processes, however, require hydrogen (H2 ) and palladium-based catalysts. Herein we propose a photocatalytic process for H2 O2 synthesis driven by metal-free catalysts with earth-abundant water and molecular oxygen (O2 ) as resources under sunlight irradiation (λ>400 nm). We use graphitic carbon nitride (g-C3 N4 ) containing electron-deficient aromatic diimide units as catalysts. Incorporating the diimide units positively shifts the valence-band potential of the catalysts, while maintaining sufficient conduction-band potential for O2 reduction. Visible light irradiation of the catalysts in pure water with O2 successfully produces H2 O2 by oxidation of water by the photoformed valence-band holes and selective two-electron reduction of O2 by the conduction band electrons.
authors.affiliation: Research Center for Solar Energy Chemistry, and Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531 (Japan). shiraish@cheng.es.osaka-u.ac.jp.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Shiraishi
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Kanazawa
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kofuji
authors.forename: Hirokatsu
authors.initials: H
authors.lastname: Sakamoto
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ichikawa
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Tanaka
authors.forename: Takayuki
authors.initials: T
authors.lastname: Hirai
keywords: graphitic carbon nitride; hydrogen peroxide; oxygen; photocatalysis; water