One-post Solvothermal Synthesis of Bismuth Oxybromides for Efficient Visible-light Photocatalytic Degradation of Methyl Parahydroxybenzoate: Effects of Alkaline and Reaction Medium

Title:One-post Solvothermal Synthesis of Bismuth Oxybromides for Efficient Visible-light Photocatalytic Degradation of Methyl Parahydroxybenzoate: Effects of Alkaline and Reaction Medium

Volume: 1

Author(s): Jiaxiu Xiao, Xiaoting Zhang, Yaoyao Huang, Xiuling Luo*Xin Xiao*

Affiliation:

• School of Chemistry, South China Normal University, Guangzhou 510006,China

• School of Chemistry, South China Normal University, Guangzhou 510006,China

Keywords: Photocatalysis, visible-light, bismuth oxybromides, methyl parahydroxybenzoate, photocatalytic mechanism, advanced oxidation processes (AOP).

Abstract:

Background: The development of high-efficiency visible-light-active photocatalysts to eliminate emerging contaminants is of great significance for environmental remediation and personal safety.

Methods: In this work, BiOBr and two oxygen-rich bismuth oxybromide (Bi₄O₅Br₂-EG and Bi₄O₅Br₂-H₂O) were synthesized by solvothermal method through the reaction of Bi³⁺ and Br- in different reaction medium (ethylene glycol or water) and alkali conditions. The composition, structure, morphology, light absorption, surface area, and surface feature of the synthetic bismuth oxybromides were systematically characterized. Due to the presence of ethylene glycol and OH-, the Bi₄O₅Br₂-EG preferentially exposes the {010} facets. The formation of hierarchical flower-like structures of Bi₄O₅Br₂-EG can be elucidated by the dissolution-recrystallization-growth mechanism. The bismuth oxybromides were then used for photocatalytic degradation of methyl parahydroxybenzoate (a commonly used preservative but exposes endocrine disrupting activity) under visible- light irradiation.

Results: Since Bi₄O₅Br₂-EG has a satisfactory band structure (bandgap energy ~2.61 eV, valence band potential +2.45 V), high surface area (49.0 m²g^-1), and negatively charged surface, its photocatalytic removal efficiency of MPHB is 46.5 and 8.04 times that of BiOBr and Bi₄O₅Br₂-H₂O, respectively. During the photodegradation reaction, holes and superoxide radicals were recognized as the key reactive oxide species.

Conclusion: The as-synthesized Bi₄O₅Br₂-EG is stable and easy to reuse, suggesting it is a potential candidate for wastewater treatment.

Cite this article as:

Xiao Jiaxiu , Zhang Xiaoting , Huang Yaoyao , Luo Xiuling*, Xiao Xin*, One-post Solvothermal Synthesis of Bismuth Oxybromides for Efficient Visible-light Photocatalytic Degradation of Methyl Parahydroxybenzoate: Effects of Alkaline and Reaction Medium, Current Chinese Engineering Science 2021; 1 (1) . https://dx.doi.org/10.2174/2665998001999200921162736