title: Highly luminescent S, N co-doped graphene quantum dots with broad visible absorption bands for visible light photocatalysts.
abstract: A facile hydrothermal synthesis route to N and S, N co-doped graphene quantum dots (GQDs) was developed by using citric acid as the C source and urea or thiourea as N and S sources. Both N and S, N doped GQDs showed high quantum yield (78% and 71%), excitation independent under excitation of 340-400 nm and single exponential decay under UV excitation. A broad absorption band in the visible region appeared in S, N co-doped GQDs due to doping with sulfur, which alters the surface state of GQDs. However, S, N co-doped GQDs show different color emission under excitation of 420-520 nm due to their absorption in the visible region. The excellent photocatalytic performance of the S, N co-doped GQD/TiO2 composites was demonstrated by degradation of rhodamine B under visible light. The apparent rate of S, N:GQD/TiO2 is 3 and 10 times higher than that of N:GQD/TiO2 and P25 TiO2 under visible light irradiation, respectively.
authors.affiliation: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 East Nanhu Road, Changchun, Jilin 130033, P. R. China. sunzc@ciomp.ac.cn.
authors.forename: Dan
authors.initials: D
authors.lastname: Qu
authors.forename: Min
authors.initials: M
authors.lastname: Zheng
authors.forename: Peng
authors.initials: P
authors.lastname: Du
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhou
authors.forename: Ligong
authors.initials: L
authors.lastname: Zhang
authors.forename: Di
authors.initials: D
authors.lastname: Li
authors.forename: Huaqiao
authors.initials: H
authors.lastname: Tan
authors.forename: Zhao
authors.initials: Z
authors.lastname: Zhao
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Xie
authors.forename: Zaicheng
authors.initials: Z
authors.lastname: Sun