Preparation Of BiOBr Composite Material For Efficient Photocatalysis

With the development of social economy,water resource,as the source of life,is increasingly polluted.As one of the most promising techniques,photocatalysis oxidation plays an important role in degradation of organic pollutants.TiO₂ has been attracting global attention due to its high chemical stability,low cost and non-toxicity.However,TiO₂ could mainly capture UV light because of its large bandgap?3.2 eV?,which greatly reduces the utilization of solar energy.BiOBr possesses good photocatalytic performance due to its unique layered structure and narrow bandgap.However,quick recombination of photogenerated electron-hole pairs still exists in pure BiOBr under visible light irradiation,which seriously affects its photocatalytic efficiency.Therefore,it is important to modify BiOBr with other semiconductor materials or non-metallic materials to reduce the recombination rate of photogenerated electron-hole pairs and improve the photocatalytic efficiency of BiOBr.In this paper,the BiOBr/Bi₂MoO₆,BiOBr/RGO,BiOBr/BiOF composites were synthesized by hydrothermal method.And these composites can suppress the recombination of photogenerated electron-hole pairs effectively.The main content is as follows:1.BiOBr/Bi₂MoO₆ composites were prepared by hydrothermal method,and their photocatalytic performance in the degradation of rhodamine B?RhB?and nitrobenzene was investigated.The results show that:?1?BiOBr/Bi₂MoO₆ composites show higher photocatalytic efficiency compared to pure BiOBr;?2?their photocatalytic efficiency is related to the doping amount of Bi₂MoO₆,and the highest photocatalytic degradation rates for RhB and nitrobenzene reach 98%for 70 min and 92%for 360 min,respectively;?3?the increase of photocatalytic performance can be attributed to low electron-hole recombination and good visible light absorption.2.GO was synthesized via modified Hummers method,and BiOBr/RGO composites were prepared through hydrothermal reduction of GO in BiOBr precursor solution.Their photocatalytic performance under visible light irradiation was investigated.The results show that:?1?BiOBr/RGO composites exhibit a better photocatalytic activity in the degradation of RhB and nitrobenzene compared with pure BiOBr;?2?the BiOBr/RGO composite with 0.6 wt.%RGO achieves a highest degradation rate of 100%for RhB?30 min?and nitrobenzene?360 min?;?3?the enhanced photocatalytic activity should be ascribed to the increased light absorption and the reduced electron-hole pair recombination with the presence of RGO.3.BiOBr/BiOF composites were synthesized via one-step hydrothermal method and their photocatalytic performance was also studied.The results show that:?1?the obtained BiOBr/BiOF composites exhibit higher photocatalytic activity than BiOBr in the degradation of RhB and nitrobenzene;?2?the photocatalytic performance of BiOBr/BiOF composites is related to the doping amount of BiOF,and the highest photocatalytic degradation rates for RhB and nitrobenzene reach 100%for 25 min and 94%for 300 min,respectively;?3?the enhanced photocatalytic activity is due to the synergistic effect from the interfacial interaction between BiOF and BiOBr,and the efficient charge transfer and separation.The h+ and ·OH radicals are the main active species for photocatalytic degradation of RhB and nitrobenzene.