One-Pot Hydrothermal Synthesis of SnO₂/BiOBr Heterojunction Photocatalysts for the Efficient Degradation of Organic Pollutants Under Visible Light

Abstract

The establishment of p-n heterojunction between semiconductors is an effective means to improve the performance of semiconductor photocatalysts. For the first time, we synthesize SnO/BiOBr heterojunction photocatalysts using a one-step hydrothermal method. Systematic material characterizations suggest that the photocatalysts consist of irregular BiOBr nanosheets with the length about 200 nm and width about 150 nm, and SnO nanoparticles are anchored uniformly onto the nanosheets. Most importantly, electrochemical characterizations including transient photocurrent profiles and electrochemical impedance spectra suggest that SnO/BiOBr heterojunctions are created, which facilitates the charge separation and transfer efficiency of photogenerated charge carriers. As such, SnO/BiOBr photocatalysts exhibit remarkable photocatalytic activities in terms of degrading a series of organic pollutants. Radical trapping experiments and electron spin resonance spectra suggest that superoxide radicals (•O) and hydroxyl radicals (•OH) are primary medium species running through the photocatalytic degradation process and enhanced photocatalytic performance.

A Novel CuBi2O4/BiOBr Direct Z‐scheme Photocatalyst For Efficient Antibiotics Removal: Synergy of Adsorption and Photocatalysis on Degradation Kinetics and Mechanism Insight

“…As BiOBr owned indirect (n=2) band transition and CuBi 2 O 4 owned direct (n=1/2) band transition, the band gap energies could be calculated by the equation: αhν=A(hν‐E g ) n . As presented in Figure b, the band gap energy of BiOBr and CuBi 2 O 4 was 2.59 eV and 1.73 eV, respectively, which was consistent with the previous reported research . In order to investigate the band edge potentials of BiOBr and CuBi 2 O 4 , ultraviolet photoelectron spectroscopy (UPS) analysis was carried out.…”

“…The discrepancy was mainly due to the oxygen vacancy derived excitation dissociation of BiOBr. [59,71] Based on the above XPS analysis, either BiOBr or CuBi 2 O 4 /BiOBr possessed oxygen vacancies, which may enable the generation of •O 2 À active species. On the other hand, as illustrated in Figure 12b, an obvious signal of •OH was existed in CB8 heterojunction sample and its intensity was increased over time, which was inconsistent with the transfer mechanisms of charges in traditional type II heterojunction.…”

“…[36,40,58] As presented in Figure 10b, the band gap energy of BiOBr and CuBi 2 O 4 was 2.59 eV and 1.73 eV, respectively, which was consistent with the previous reported research. [18,59] In order to investigate the band edge potentials of BiOBr and CuBi 2 O 4 , ultraviolet photoelectron spectroscopy (UPS) analysis was carried out. According to previous reports, the valence band energy was determined by subtracting the width of the He 1 UPS spectra from the excitation energy (21.22 eV).…”

Novel P-n Li2SnO3/g-C3N4 Heterojunction With Enhanced Visible Light Photocatalytic Efficiency Toward Rhodamine B Degradation

“…Constructing visible light-responsive Li 2 SnO 3 -based heterojunction photocatalysts to make full use of sunlight is thus an important goal. This kind of system, where a heterojunction is formed between a visible light-and a UV light-responsive photocatalyst, has received some attention in recent years (Pan et al, 2012;Wu et al, 2017;Liu et al, 2018;Qiao et al, 2018;Wang et al, 2018a;Hafeez et al, 2019). For instance, ZnFe 2 O 4 /TiO 2 heterojunctions exhibited outstanding photocatalytic degradation of bisphenol A under visible light irradiation (Nguyen et al, 2019).…”

Deep Eutectic Solvent‐Assisted Synthesis of Ternary Heterojunctions for the Oxygen Evolution Reaction and Photocatalysis

“…To overcome these issues, modifying the morphological structure and the construction of p–n semiconductor heterojunctions and constructing ternary heterojunctions is expected to result in improved photocatalytic activity and chemically stable materials . Recently, many researchers have reported bismuth oxyhalides (BiOX, X=Cl, I, Br) and their heterojunctions in photocatalytic water splitting, owing to their unique physicochemical properties . Moreover, BiOCl/BiVO 4 p–n heterojunctions have been reported to enhance the photocatalytic activity and pollutant degradation under visible‐light irradiation …”