| Solar energy is one of the best clean energy.How to use solar energy for solving the environment pollution and energy crisis has received strong concerns.Photocatalytic technology is a new kind of environmental friendly green technology,which has been widely studied in recent decades.A lot of work has been done in the field of photoelectric conversion,photolysis of water to yield hydrogen fuel,photooxidization of hazardous substances,photo-induced super-hydrophilicity,artificial photosynthesis.Traditional photocatalyst has wide band gap and weak catalytic activity,thus it is important to develop new photocatalyst materials for environmental improvement and building clean energy system.In this paper,surrounding a new photocatalyst Ag3PO4,we prepared a series of different structure and morphology Ag3PO4 photocatalyst and ZnBiYO4-Ag3PO4 heterojunction.The structure,morphology,optical properties and photocatalytic properties were characterized by different methods.By above study,we revealed the relationship between the microstructure and photocatalytic properties.The current investigation provided a scientific reference to prepare a new photocatalyst.The main content of this paper is summarized as follows:(1)Shape controlled synthesis and photocatalytic activity of Ag3P04 were studied.Acetic acid(Ace)and polyacrylamide(PAM)were used as template agent to synthesize Ag3PO4 crystal.By changing the dosage of acetic acid and polyacrylamide,Ag3PO4 photocatalyst with different size and different surface morphology could be achieved.With the increasing concentration of acetic acid,the photocatalytic activity of Ag3PO4 sample reduced gradually,and the grain size enlarged gradually,meanwhile the shape of Ag3PO4 sample was gradually changed as regular smooth polyhedron no longer rough sphere.When the concentration of polyacrylamide was 5 mmol/L,the photocatalytic activity of Ag3PO4 sample was the best.With the increasing concentration of polyacrylamide,the grain size of Ag3PO4 sample enlarged gradually,and the shape transformed from sphere to polyhedron gradually changed.(2)ZnBiYO4 photocatalyst was synthesized by high temperature solid phase sintering method.It was characterized by XRD,UV-vis,SEM-EDS and XPS technologies.The analysis showed that ZnBiYO4 crystallized with a tetragonal spinel structure by space group 141/A.The lattice parameters for ZnBiYO4 were a = b =11.176479 A and c = 10.014323 A.The band gap of ZnBiYO4 was estimated to be 1.68 eV.Compared with N-doped TiO2,ZnBiYO4 owned higher catalytic activity under visible light irradiation.(3)Co-deposition precipitation method was used to synthesize ZnBiYO4-Ag3PO4 heterojunction.According to characteristic techniques,we found that ZnBiYO4-Ag3PO4 crystallized well and the band gap of this sample was 2.17 eV.The angular surface of ZnBiYO4 particle was covered by flocculent Ag3PO4.The photocatalytic activity experiments were evaluated by degradation of methyl orange(MO).The effects of pH value and rate of composite catalyst were investigated on the photodegradation efficiency.The results proved that photodegradation efficiency was the highest when the pH value = 5-7.Besides,the photocatalytic activity of 30%ZnBiYO4-Ag3PO4 was comparable to Ag3PO4 but the stability of 30%ZnBiYO4-Ag3PO4 was better than Ag3P04.At last,photocatalytic reaction mechanism of ZnBiYO4-Ag3PO4 sample was discussed.The experiment results showed that compared with hydroxyl radical,superoxide anion and hole took the dominant role in the process of photodegradation of methyl orange. |
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