Preparation And Photodegradation Performance Study Of Composite Materials Based On Nano-tungsten Trioxide

Photocatalytic technology is considered as a method with great application prospects to remove organic pollutants.Nowadays,many studies are devoted to the development of semiconductor photocatalyst materials for water treatment,such as Ti O₂,WO₃,etc.However,a single semiconductor material has poor photocatalytic performance due to the low utilization rate of photogenerated electron-hole pairs.Therefore,it is necessary to modify a single semiconductor material,such as ion doping and constructing a heterojunction structure,to enhance the photocatalytic activity.Although nano-powder photocatalytic materials have high photocatalytic activity,they are not ideal in actual water treatment applications because the photocatalyst is difficult to remove from water after photocatalytic treatment,and it is difficult to recycle and reuse.Meanwhile,the photocatalytic material remains in the water,which can easily cause secondary pollution.Therefore,the preparation of the photocatalytic material into a thin film material can effectively solve the problem that the photocatalyst is difficult to recycle,and can be used in actual water treatment.In this paper,several different composite materials and photocatalytic film materials were synthesized based on WO₃,and the photodegradation activity of composite materials was discussed using water-soluble dyes and antihypertensive drug metoprolol as target pollutants.The main research results are as follows:（1）Two-dimensional black phosphorus-supported WO₃ composites（WO₃-BPNs）were synthesized by using a combination of hydrothermal method,liquid phase stripping method and co-precipitation method.A series of characterization techniques such as XRD,XPS,UV-vis,etc.confirmed that the composite material has excellent optical properties.The photodegradation tests confirmed that the composite materials greatly enhanced the photocatalytic activity compared with pure WO₃ and BPNs.After 120 min of photodegradation reaction,the composite material can remove 92%Rh B and 87%MET,respectively,and the composite material has also good stability.The BPNs in the WO₃-BPNs50 heterojunction acts as a co-catalyst to receive and transfer photo-generated electrons during the photocatalytic reaction process,thereby effectively reducing the recombination of photo-generated electron-hole pairs and significantly improving the photocatalytic performance.Finally,the intermediate products in the photodegradation process of MET were determined by LC/MS analysis,and the possible degradation pathways of MET photodegradation were proposed.（2）A novel hollow spherical WO₃/Ti O₂ heterojunction photocatalyst was prepared by a combination of hydrothermal and calcination methods.SEM results show that the 10%WO₃/Ti O₂ composite sample has a hollow spherical structure,and the BET results also confirm that the 10%WO₃/Ti O₂ composite sample has the largest specific surface area.Hollow spherical WO₃/Ti O₂ composite material enhanced the photodegradation performance compared to pure WO₃ and Ti O₂.A series of characterization techniques such as XRD,XPS,UV-vis,etc.were tested on the composite materials.The SEM results showed that the 10%WO₃/Ti O₂composite sample has a hollow spherical structure,and the BET result also confirmed that the10%WO₃/Ti O₂ composite sample has the largest specific surface area.The results of the photodegradation test showed that the 10%WO₃/Ti O₂ sample exhibited enhanced photocatalytic performance degrading MB and MET under visible light.Compared with pure Ti O₂ and WO₃,the 10%WO₃/Ti O₂ sample can remove 87.8%MB and 67.1%MET,respectively,after 120 min photodegradation reaction.Finally,the photodegradation mechanisms of the 10%WO₃/Ti O₂ sample are also discussed.Ti O₂ acts as a photo-generated hole receptor in the heterojunction,which effectively reduces the recombination of photo-generated carriers and improves the photocatalytic performance.（3）Two-dimensional WO₃ nanosheets（2D-WO₃）are obtained by ultrasonically peeling WO₃ from bovine serum albumin solution（BSA）,and then 2D-WO₃ was added to cellulose acetate（CA）to obtain 2D-WO₃/CA flexible composite film material.When the addition amount of 2D-WO₃ was 0.3 g,2D-WO₃ was firmly combined with the CA film to obtain a strong 2D-WO₃/CA flexible film with higher photocatalytic activity.The results of the photodegradation test showed that the 2D-WO₃/CA film-0.3 sample can remove 90.8%MB.In addition,the 2D-WO₃/CA films show good stability and recyclability,and show a good application prospect in the photocatalytic treatment of pollutants.