title: Facile synthesis of AgI/BiOI-Bi2O3 multi-heterojunctions with high visible light activity for Cr(VI) reduction.
abstract: AgI sensitized BiOI-Bi2O3 composite (AgI/BiOI-Bi2O3) with multi-heterojunctions was prepared using simple etching-deposition process. Different characterization techniques were performed to investigate the structural, optical and electrical properties of the as-prepared photocatalysts. It was found that the ternary AgI/BiOI-Bi2O3 composite exhibited: (1) improved photocurrent response, (2) smaller band gap, (3) greatly reduced charge transfer resistance and (4) negative shift of flat band potential, which finally led to easier generation and more efficient separation of photo-generated electron-hole pairs at the hetero-interfaces. Thus, for the reduction of Cr(VI), AgI/BiOI-Bi2O3 exhibited excellent photocatalytic activity under visible light irradiation at near neutral pH. AgI/BiOI-Bi2O3 was optimized when the initial molar ratio of KI to Bi2O3 and AgNO3 to Bi2O3 was 1:1 and 10%, respectively. The estimated kCr(VI) on optimized AgI/BiOI-Bi2O3 was about 16 times that on pure Bi2O3. Good stability was also observed in cyclic runs, indicating that the current multi-heterostructured photocatalyst is highly desirable for the remediation of Cr(VI)-containing wastewater.
authors.affiliation: School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, China; The Brook Byer Institute for Sustainable Systems and School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta 30332, USA.
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.affiliation: School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Shi
authors.affiliation: School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, China.
authors.forename: Enqin
authors.initials: E
authors.lastname: Liu
authors.affiliation: The Brook Byer Institute for Sustainable Systems and School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta 30332, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Crittenden
authors.affiliation: School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, China.
authors.forename: Xiangjuan
authors.initials: X
authors.lastname: Ma
authors.affiliation: School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, China. Electronic address: yqcong@hotmail.com.
authors.forename: Yanqing
authors.initials: Y
authors.lastname: Cong
keywords: AgI; BiOI-Bi(2)O(3); Cr(VI) reduction; Heterojunction; Visible light