BiOBr/MoS₂ catalyst as heterogenous peroxymonosulfate activator toward organic pollutant removal: Energy band alignment and mechanism insight

Area of Science:

• Materials Science
• Environmental Chemistry
• Catalysis

Background:

• Heterogeneous catalysts are crucial for peroxymonosulfate (PMS) activation in environmental remediation.
• Developing efficient and stable catalysts is essential for treating complex industrial wastewater.

Purpose of the Study:

• To design and synthesize a novel 2D/2D BiOBr/MoS2 heterojunction for enhanced PMS activation.
• To investigate the catalytic performance of the heterojunction for organic dye oxidation, Cr(VI) reduction, and degradation of emerging organic pollutants.
• To elucidate the mechanism of PMS activation and pollutant degradation within a photo-Fenton system.

Main Methods:

• Co-precipitation synthesis of the 2D/2D BiOBr/MoS2 heterojunction.
• Characterization of the heterojunction's structure, morphology, and electronic properties.
• Evaluation of catalytic activity in PMS activation for organic pollutant degradation and Cr(VI) reduction.
• Scavenging experiments to identify reactive oxygen species and understand the reaction mechanism.

Main Results:

• The BiOBr/MoS2 heterojunction exhibited a Type-II band alignment, facilitating efficient charge carrier transfer.
• The catalyst demonstrated high efficiency in oxidizing organic dyes and reducing Cr(VI).
• In a photo-Fenton system, the heterojunction effectively activated PMS to generate SO4•−, •OH, and O2•− radicals, degrading phenol, bisphenol A, and carbamazepine.
• The catalyst showed excellent stability and potential for practical application in wastewater treatment.

Conclusions:

• The designed 2D/2D BiOBr/MoS2 heterojunction is a highly effective catalyst for PMS activation.
• The intimate interfacial coupling and matched energy levels are key to its enhanced catalytic performance.
• This study offers valuable insights into the application of advanced heterojunction materials for complex wastewater treatment.