DFT insights into the migration of effective electrons towards O2 for [rad]OH formation over electron-rich sites on BiOBr (0 0 1) surface

Abstract

Electron migration and photo-reaction selectivity are closely related to catalyst crystal surface. Hence, it is rather significant for imaging clearly the electron migration and its electron density effect on the catalyst surface. In this work, the BiOBr (001) surfaces with Bi-, O- and Br-terminated are designed to observe the behaviors of electron distribution and O2 activation. More electrons are diffused in the electron-rich sites (ERS) via the electron density difference (EDD). The reaction pathways for the hydrogenation of O2 at each ERS are investigated to explore the effect of effective electron quantity for OH formation. Besides, the more electrons are transferred to O2, the less energy is required for breaking out OO bond to boost the generation of OH. The interface Bi atoms can promote the effective electrons to O2 for improving OH formation. For BiOBr (001) surfaces with O- and Br-terminated, the steric hindrance of interface atoms obviously increases the electron transfer distance and limits the electrons to O2. This work gives deep theoretical insights into the migration of effective electrons towards photocatalytic O2 hydrogenation on the BiOBr (001) surface and provides new perspective for understanding the structure-performance relationship rule.