Substitution Boosts Charge Separation for High Solar-Driven Photocatalytic Performance.
Bandgap engineering of photocatalysts is a common approach to achieving high effective utilization of solar resource. However, the difficulty in achieving bandgap narrowing and high activity simultaneously seems to be irreconcilable via the traditional modification pathway. Herein, we have substituted iodine for a fraction of bromine atoms in BiOBr to overcome this restriction and provided some deep-seated insights into how the substitution boosts the photocatalytic properties. The substituted BiOBr0.75I0.25exhibited exceptional photoactivity, with photon-to-current conversion efficiency approximately 6 times greater than TiO2in UV region, and more than 10 times higher than BiOBr or BiOI in visible-light region. We found that the substitution narrowed the bandgap, facilitated the diffusion of electron with small effective mass, as well as induced oxygen vacancies on [Bi2O2]2+layers. By virtue of the stronger dipole moments produced, the enhancement of intrinsic electric fields between [Bi2O2]2+and halogen slabs was achieved in BiOBr0.75I0.25; thereby the distance the photogenerated electron could diffuse was sufficient to inhibit the recombination. Our findings not only shed light on the potential properties of hybrid-halide photocatalysts but also provide a strategy for developing high efficiency catalysts.
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China.|University of Chinese Academy of Sciences , Beijing 100039, China.
Gong
G
Zhang
Beijing Computational Science Research Center , Beijing 100084, China.
Le
L
Zhang
Department of Chemistry, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Beijing Key Laboratory for Microanalytical Methods and Instrumentation, Tsinghua University , Beijing 100084, China.
Yang
Y
Liu
Beijing Computational Science Research Center , Beijing 100084, China.
Limin
L
Liu
Department of Civil and Environmental Engineering, University of Delaware , Newark, Delaware 19716, United States.
Chin-Pao
CP
Huang
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China.|University of Chinese Academy of Sciences , Beijing 100039, China.
Huijuan
H
Liu
Department of Chemistry, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Beijing Key Laboratory for Microanalytical Methods and Instrumentation, Tsinghua University , Beijing 100084, China.
Jinghong
J
Li
BiOBr; iodine; photoactivity; substitution; vacancy