| At present,semiconductor photocatalytic technology has been widely recognized in the field of environmental pollution and energy sustainable development.Bismuth-based photocatalysts are a kind of visible light driven materials that have been reported more in recent years,Bi2WO6 and BiOX(X =C1,Br,I)have appropriate band gap width and special layered structure,which have attracted the attention of many researchers.However,the low visible light utilization rate and the easy recombination of photo-generated electron-hole pair of the material itself greatly inhibit its catalytic activity,so further improving the photocatalytic activity of such semiconductor catalyst materials,it is possible to meet its large-scale application under visible light irradiation.Bi2WO6 and BiOBr were modified on the basis of bismuth catalyst in this study,including three parts:(1)Preparation of Bi/Bi3.g4W0.,6O6.24 supported photocatalyst with oxygen vacancy by solvothermal method;(2)Preparation of Bi4O5Br2/Bi24O31Br10 heterojunction photocatalyst by solvothermal method;(3)Preparation of Ag/BiOBr supported photocatalyst by chemical reduction method.The phase,morphology and optical properties of the product were characterized by XRD,SEM,HRTEM,UV-vis DRS,XPS,PL and other techniques.The photocatalytic properties of the samples were evaluated by simulating the degradation degree of 10 mg·L-1 Rhodamine B(RhB)solution and phenol solution under simulated visible light,and the possible photocatalytic mechanism was explored.The details are as follows:(1)Bi/Bi3.84W0.16O6.24 supported photocatalyst was synthesized by using ethylene glycol as solvent and adjusting precursor pH = 11 reaction at 160?for 8 h.Compared with monomer Bi2WO6 and Bi3.84W0.16O6.24,the obtained Bi/Bi3.84W0.16O6.24 photocatalyst showed excellent photocatalytic activity against RhB solution under 200 W tungsten lamp.After 15 min of light exposure,the degradation efficiency of RhB solution was nearly 96%.After 5 cycles of experiments,the photodegradation rate of RhB solution by Bi/Bi3.84W0.16O6.24 catalyst did not decrease significantly,showing good photocatalytic stability.Mechanism investigation showed that the high photocatalytic activity of Bi/Bi3 84W0.16O6.24 was attributed to the synergistic effect of oxygen defects and metal Bi.(2)Bi4O5Br2/Bi24O31Br10 heterojunction photocatalyst with excellent performance were prepared by using ethylene glycol as solvent and adjusting precursor pH = 9 reaction at 160? for 4 h.The degradation efficiency of phenol solution under 500W xenon lamp for 5 h was 60.3%,which was 44.7%higher than that of BiOBr monomer prepared under the condition of pH = 4.After three recycling and recycling experiments,it still had high catalytic activity and certain stability.The results showed that the existence of heterogeneous structure can improve the transfer rate of photogenic carriers,and the migration behavior of photo-generated carriers promotes the efficient separation of photo-generated electron-hole pairs,reduces the recombination probability,and improves the catalytic performance.(3)BiOBr micro/nano materials exposed facets(110)was prepared by hydrothermal method,and then spread in a certain amount of AgN03 solution(0.001 mol·L-1),Ag/BiOBr supported photocatalyst was obtained by adding NaBH4 solution(0.05 mol L-1)under the condition of 30 ? water bath stirring for 4 h.The results showed that under 500 W xenon lamp irradiation,Ag/BiOBr with 0.6 wt%showed better photocatalytic activity than BiOBr monomer,and the degradation efficiency of phenol solution was 76.1%after 5 h of illumination,higher than 53.9%of BiOBr monomer.Compared with BiOBr,Ag/BiOBr has a better catalytic effect in the degradation of phenol solution,which may be due to the surface plasmon resonance effect generated by metal Ag and BiOBr and the fact that metal Ag can effectively inhibit the recombination of photo-generated electron-hole pairs.In brief,we prepared bismuth tungsten oxide and bismuth bromide oxide with excellent performance,which broadened the research and development of controllable synthesis of bismuth based photocatalytic composite material,and provided experimental basis for visible light responsive photocatalyst for wastewater degradation. |
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