Synthesis Of Bismuth Oxybromide Photocatalyst Based On Crystal Facet And Enhanced Their Photocatalytic Activity

Photocatalysis has become an effective solution to solve energy shortages and environmental pollution problems.The development of high-performance photocatalytic materials has always been a key issue in the development of photocatalytic technologies.However,the existing photocatalytic materials generally have two problems of low solar energy utilization and low quantum efficiency,which become the bottleneck of the development of photocatalytic technologies.Among the photocatalytic materials,BiOBr has become one of the research hotspots with its unique crystal structure and electronic structure,excellent visible light absorption capacity,high stability and low toxicity.In this paper,facet controllable synthesis,construct a high-quality interface heterojunction grown on the facet and the structure contains oxygen vacancies facet,aiming at further improving the photocatalytic activity of BiOBr and broadening its application range.The main research contents are as follows:1.Using Bi₂O₃ nanorods and HBr acid as raw materials,using glucose as a structure-directing agent,1D rod-like Bi OBr with exposed?110?facet was prepared using a simple hydrothermal method.The effects of glucose concentration,reaction time and reaction temperature on the structure and photocatalytic properties of BiOBr were studied.The experimental results showed that the exposed?110?facet Bi OBr degraded RhB?20mg/L?completely within 15 min under visible light,and their enhanced photocatalytic activity was attributed to the significant increase of the photoelectron reduction capacity,effective electron transfer and current carrying.Separation.Free radical capture experiments demonstrate that·O₂^-is the main active species of photocatalysis.This work will provide a simple way to control the synthesis of exposed?110?BiOBr.2.By increasing the concentration of glucose,a BiOBr precursor with a metallic?Bi?-modified exposed?110?facet was synthesized,and then the precursor was calcined in air at 400°C for 2 hours to synthesize a one-dimensional BiOBr-Bi₄O₅Br₂ heterojunction.The experimental results show that BiOBr-Bi₄O₅Br₂ heterojunction shows higher photocatalytic activity than pure BiOBr and Bi₄O₅Br₂.Using DS2 as a catalyst,RhB?20mg/L?can be completely degraded under visible/solar light irradiation for 10 min and 5min.This enhanced photocatalytic performance is due to the synergy effect of a suitable band,high quality interface,and one-dimensional layered structure of BiOBr and Bi₄O₅Br₂.The free radical trapping experiment proved that the hole?h⁺?and superoxide radical?·O₂^-?are the main photocatalytic active species.This work provides an effective method for design and synthesis high-quality interface heterojunctions.3.Using Bi?NO₃?₃·5H₂O and cetyltrimethylammonium bromide?CTAB?as raw materials,through the control of the ratio of ethylene glycol and water,hydrothermal synthesis of exposed?001?facet with oxygen vacancies BiOBr nanosheets.The results showed that oxygen vacancies BiOBr exhibited higher photocatalytic activity than pure BiOBr.Under solar light irradiation,oxygen vacancies Bi OBr?001?degraded MO?10mg/L?completely within 15 min.The enhanced photocatalytic performance is attributed to sufficient oxygen vacancies,and the formed electron traps can increase the separation efficiency of electrons and holes.The free radical trapping experiment proved that the hole?h⁺?and superoxide radical?·O₂^-?are the main photocatalytic active species.This work will provide a new approach for the design and synthesis of oxygen vacancies photocatalysts in photocatalytic applications.