Photocatalytic Properties Of Bismuth Chlorooxide-Graphite-Like Carbon Nitride Heterostructured Materials

Photocatalytic technology has great potential to solve energy shortage and environmental pollution problems.The core of the rapid development of photocatalysis technology is the type and selection of photocatalysts.Choosing the right photocatalyst can effectively improve its efficiency.Among the wide variety of photocatalysts,bismuth chloride oxide（BiOCl）is a typical layered semiconductor photocatalyst that has been widely used in photocatalytic reactions due to its low toxicity,cheap and easy availability,unique crystal surface effect and easily adjustable electronic band structure.However,BiOCl still suffers from the disadvantages of high photogenerated electron-hole pair complexation rate,slow migration rate and low visible light utilization,which limit BiOCl in photocatalytic applications.In order to further improve the photocatalytic performance of BiOCl,this paper focuses on two strategies to modify BiOCl,namely,surfactant（PVP）modification and construction of BiOCl-graphite-like carbon nitride heterostructures.The specific studies are as follows:（1）Visible-light-driven BiOCl nanosheets were successfully synthesized by polyvinylpyrrolidone（PVP）-assisted solvothermal method.The effect of PVP on the structure and morphology of the products was investigated.BiOCl nanosheets with highly exposed（110）crystalline planes were successfully synthesized by the solvothermal method at 160℃ for 3 h in a solution containing 0.8 g PVP.The photodegradation ability of BiOCl nanosheets against rhodamine（Rh B）was simulated under visible light irradiation of sunlight by xenon lamp.The results showed that the PVP-modified BiOCl nanosheets exhibited excellent photocatalytic activity.After three times of photodegradation recycling cycle test,the samples still show good catalytic performance.（2）BiOCl/g-C₃N₄ heterojunction photocatalysts were successfully prepared by the solvothermal method using NaCl,Bi（NO₃）₃·5H₂O and graphite-like carbon nitride（g-C₃N₄）as precursors,and the photocatalytic performance of the complexes was characterized under visible light using methyl orange solution as degradants,and the effect of different BiOCl:g-C₃N₄ ratios on the efficiency of photocatalytic degradation of methyl orange（MO）.The results showed that BiOCl/g-C₃N₄ had higher photocatalytic activity than BiOCl and g-C₃N₄ alone,and the heterojunction catalyst with a BiOCl:g-C₃N₄ molar ratio of 1.5:1 showed the highest photocatalytic activity.Based on the characterization by XRD,SEM,TEM,BET and UV-vis,it can be inferred that the heterojunction formed between BiOCl and g-C₃N₄ can effectively separate photogenerated electrons and holes,which is the main reason for the enhanced photocatalytic activity.