title: Unique electronic structure induced high photoreactivity of sulfur-doped graphitic C3N4.
abstract: Electronic structure intrinsically controls the light absorbance, redox potential, charge-carrier mobility, and consequently, photoreactivity of semiconductor photocatalysts. The conventional approach of modifying the electronic structure of a semiconductor photocatalyst for a wider absorption range by anion doping operates at the cost of reduced redox potentials and/or charge-carrier mobility, so that its photoreactivity is usually limited and some important reactions may not occur at all. Here, we report sulfur-doped graphitic C(3)N(4) (C(3)N(4-x)S(x)) with a unique electronic structure that displays an increased valence bandwidth in combination with an elevated conduction band minimum and a slightly reduced absorbance. The C(3)N(4-x)S(x) shows a photoreactivity of H(2) evolution 7.2 and 8.0 times higher than C(3)N(4) under lambda > 300 and 420 nm, respectively. More strikingly, the complete oxidation process of phenol under lambda > 400 nm can occur for sulfur-doped C(3)N(4), which is impossible for C(3)N(4) even under lambda > 300 nm. The homogeneous substitution of sulfur for lattice nitrogen and a concomitant quantum confinement effect are identified as the cause of this unique electronic structure and, consequently, the excellent photoreactivity of C(3)N(4-x)S(x). The results acquired may shed light on general doping strategies for designing potentially efficient photocatalysts.
authors.affiliation: Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Liu
authors.forename: Ping
authors.initials: P
authors.lastname: Niu
authors.forename: Chenghua
authors.initials: C
authors.lastname: Sun
authors.forename: Sean C
authors.initials: SC
authors.lastname: Smith
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Chen
authors.forename: Gao Qing Max
authors.initials: GQ
authors.lastname: Lu
authors.forename: Hui-Ming
authors.initials: HM
authors.lastname: Cheng