Improved photoelectric properties of BiOBr nanoplates by co-modifying SnO2 and Ag to promote photoelectrons trapped by adsorbed O2

Abstract

It is highly desired to improve the photoelectric property of nanosized BiOBr by promoting the photogenerated charge transfer and separation. Herein, SnO 2 and Ag comodified BiOBr nanocomposites (Ag-SO-BOB) have been prepared through a simple one-pot hydrothermal method. Surface photovoltage response of BiOBr nanoplates has 4.1time enhancement after being modified with SnO 2 nanoparticles. Transient-state surface photovoltage (TS-SPV) and the atmosphere-controlled steady-state surface photovoltage spectroscopy (AC-SPS) confirmed that this exceptional enhancement of the photovoltage response can be ascribed to the coupled SnO 2 acting as platform for accepting the photoelectrons from BiOBr so as to prolong the lifetime and enhance charge separation. Remarkably, the surface photovoltage response can be further enhanced by synchronously introducing Ag nanoparticles, which is up to 15.4-times enhancement compared with bulk BiOBr nanoplates. The enhancement can be attributed to the improved O 2 adsorption by introducing Ag to further enhance charge separation. Finally, the synergistic effect of SnO 2 and Ag co-modification enhances the surface photovoltage response due to the enhanced charge separation and promoted O 2 adsorption, which is also confirmed through photoelectrochemistry and photocatalytic experiment.

An Electroactive BiOBr/PVDF/CB Film Electrode for Electrochemical Extraction of Bromine Ions from Brines

“…It has been widely used in environmental protection due to its unique layered structure and efficient photocatalysis. − In addition, Br – can easily escape from the interlayers owing to the weak van der Waals interaction and the presence of reduction potential; thus the corresponding extraction sites were generated to selectively reinsert Br – . Based on this remarkable electrochemical property, − our group extended the application of BiOBr to the selective extraction of Br – . For example, Wang et al prepared a BiOBr film on carbon paper by a three-step electrochemical method for Br – extraction by using a photoassisted ESIX technology .…”

Regulating electronic properties of BiOBr to enhance visible light response via 3d transition metals doping: DFT + U calculations

“…More importantly, BiOBr shows an appropriate indirect band gap, implies that photogenerated e − must cross a certain k‐ space to be emitted to CB, further to prevent the recombination rates of photoexcited e − ‐ h + pairs [5, 6]. Nevertheless, there exist low quantum efficiency and fast photoexcited e − ‐ h + pairs recombination rates as the “bottleneck” for satisfying with the requirement of practical applications [7, 8]. Therefore, it is rather critical to explore novel strategies to improve the photocatalytic performance of BiOBr.…”

Regulating electronic properties of BiOBr to enhance visible light response via 3d transition metals doping: DFT+U calculations

“…More importantly, BiOBr shows an appropriate indirect band gap, implies that photogenerated emust cross a certaink-space to be emitted to CB, further to prevent the recombination rates of photoexcitede --h + pairs [5,6] . Nevertheless, there exist low quantum efficiency and fast photoexcitede --h + pairs recombination rates as the "bottleneck" for satisfying with the requirement of practical applications [7,8] . Therefore, it is rather critical to explore novel strategies to improve the photocatalytic performance of BiOBr.…”