Moderate band-gap-broadening induced high separation of electron-hole pairs in Br substituted BiOI: a combined experimental and theoretical investigation

被引：57

作者：

Huang, Hongwei ^{[1
]}

Li, Xiaowei ^{[1
]}

Han, Xu ^{[1
]}

Tian, Na ^{[1
]}

Zhang, Yihe ^{[1
]}

Zhang, Tierui ^{[2
]}

机构：

[1] China Univ Geosci, Sch Mat Sci & Technol, Natl Lab Mineral Mat, Beijing Key Lab Mat Utilizat Nonmetall Minerals &, Beijing 100083, Peoples R China

[2] Chinese Acad Sci, Tech Inst Phys & Chem, Key Lab Photochem Convers & Optoelect Mat, Beijing 100190, Peoples R China

来源：

PHYSICAL CHEMISTRY CHEMICAL PHYSICS | 2015年 / 17卷 / 05期

基金：

国家高技术研究发展计划(863计划);

关键词：

PHOTOCATALYTIC ACTIVITY; SOLVOTHERMAL SYNTHESIS; CRYSTAL-STRUCTURE; EFFICIENT; MICROSPHERES; TIO2; NANOPARTICLES; DEGRADATION; IRRADIATION; PERFORMANCE;

D O I：

10.1039/c4cp04842c

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

We, for the first time, demonstrate band-gap-broadening as a new approach to remarkably enhance the photocatalytic activity of Br- substituted BiOI photocatalysts, which were fabricated via a facile chemical precipitation route. The successful incorporation of Br- ions into the crystal lattice of BiOI was confirmed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HRTEM). The photocatalytic experiments demonstrated that all of the Br-BiOI samples exhibited highly improved photocatalytic performances pertaining to rhodamine B (RhB) and phenol degradation under visible light (lambda > 420 nm). The active species trapping and electron spin resonance (ESR) experiments also suggested that more superoxide radicals (O-center dot(2)-), serving as the main active species, were generated over Br-BiOI than pristine BiOI in the photooxidation process. Based on the results from experiments and theoretical calculations, the enhancement of photocatalytic activity should be attributed to the lowered valence band (VB) potential and enlarged band gap induced by the Br- replacement, which greatly facilitated the high separation of photoinduced electron-hole pairs, as verified by the photoluminescence (PL) experiments, electrochemical impedance spectra (EIS) and Bode-phase spectra. This work sheds light on a new method to improve the photocatalytic performance of photocatalysts.

引用

页码：3673 / 3679

页数：7