Design Synthesis Of Silver Heterojunction Photocatalysis And Study On Visible Light Catalytic Performance

Rapid economic growth,rapid urbanization and industrialization have extensively developed natural resources.A large number of uncontrolled and untreated heavy metals and organic wastewater are discharged into the environment,which poses a serious threat to the biological and abiotic elements of the ecosystem caused by global environmental differences.Semiconductor photocatalysis technology can use abundant solar energy.As an effective photocatalyst,Ag3PO4 is used to evaluate O2 and degrade dyes under sunlight.About 90%quantum efficiency can be achieved at a wavelength of about 420 nm.Faceted photocatalytic effect can be achieved by adjusting its morphology.However,the monomer Ag3PO4 has low response to visible light,high recombination rate of photogenerated electrons,and is prone to photocorrosion under visible light irradiation.In order to enhance the photocorrosion resistance and photocatalytic activity of Ag3PO4,the composite photocatalysts of ZnWO4,Cs3PW12O40(abbreviated as CsPW)and Ag3PO4 were prepared with Ag3PO4 as the main research object.Rhodamine B(RhB)was used as the dye degradation model to explore its photocatalytic degradation activity.XRD,SEM,TEM,XPS,UV vis and FT-IR were used to analyze the crystal form and the morphology was characterized.At the same time,considering the practical application of catalysts,cyclic experiments were carried out,and the effects of e-,h+and-OH on the photocatalytic oxidation of RhB in the photodegradation process,respectively,as well as the catalytic mechanism and photocorrosion resistance of the composites were explored.The mechanism of the photocatalytic oxidation of RhB by the composites is proposed and discussed.The main contents and results are as follows:1.The ZnWO4/Ag3PO4 heterojunction photocatalyst was synthesized by a dissolution and precipitation method.The ZnWO4/Ag3PO4 composite was characterized by XRD,SEM,TEM,XPS,UV-Vis,FT-IR and other methods.RhB was selected as the dye for degradation.model to evaluate the photocatalytic oxidation ability of the composites.The results show that the composite material has a narrow band gap value of 2.26 eV,and the 7%ZnWO4/Ag3PO4 composite material has a good degradation effect on RhB,the degradation rate of RhB was 94.0%after 120 min of visible light irradiation.The Nyquist curve shows that the 7%ZnWO4/Ag3PO4 composite has the smallest radius,indicating that the separation of photogenerated electron-hole pairs is more effective,the interface charge transfer is faster,and it has good stability.The active species capture tests show that h+ and ·OH are possible reactive species in the degradation reaction.The enhanced photocatalytic activity might be due to the formation of a p-n heterojunction system composed of Ag3PO4,Ag and ZnWO4.2.The Cs3PW12O40/Ag3PO4(CsPW/Ag3PO4)heterojunction photocatalyst in this study was prepared using a chemical precipitation method.Spherical CsPW particles were successfully deposited on Ag3PO4 nanocrystals,The catalyst activity in relation to rhodamine B(RhB)degradation was evaluated under visible light(λ>420 nm).The Z-scheme 3%CsPW/Ag3PO4 heterojunction photocatalyst has a higher photocatalytic ability compared with the single-component photocatalyst CsPW or Ag3PO4 and the degradation rate was 96.98%.The comparatively high photocatalytic performance can be attributed to the high matching of the energy band position and close interface contact,suggesting an enhanced separation efficiency of the photoinduced carriers of the CsPW/Ag3PO4 heterojunction photocatalyst.The reactive species trapping experiments demonstrated photogenerated holes(h+)and superoxide radicals(·O2-)to be the main active components of photocatalytic degradation.A possible photocatalytic mechanism is subsequently proposed.3.Different influencing factors were investigated for ZnWO4/Ag3PO4 and CsPW/Ag3PO4 heterojunction photocatalysts respectively.When the catalyst dosage is 0.1500 g,0.1010 g,pH=6.0,and the initial concentration is 10.0 mg/L,the degradation effect is the best.At the same time,when MO and MB are used as different dye pollutants,the synthesized catalysts have all of them.At the same time,in order to explore the treatment of refractory pollutants by the synthesized catalyst,phenol and tetracycline were used as degradants to explore their degradation ability,and the degradation rates were 96.5%and 89.4%,respectively,indicating that the synthesized catalyst can be used.Treatment of refractory pollutants in water.