Preparation And Properties Of ZnO/Ag₂O Nanocomposites Based On Mechanical Force Chemical Method

ZnO is a common wide-bandgap semiconductor with low cost,easy preparation,abundant source,non-toxicity,high activity and chemical stability.It is one of the most important semiconductors in the field of photocatalysis.However,the wide application of ZnO is still a huge challenge due to its weak responsiveness under visible light and the rapid recombination of photogenerated electron-hole pairs.Studies have shown that ZnO can be effectively combined with narrow-bandgap semiconductor materials to improve photocatalytic performance.In this paper,ZnO/Ag₂O composite semiconductor materials were successfully prepared by mechanical chemistry of ZnO and narrow-bandgap semiconductor Ag₂O.Then we studied the photocatalytic properties and photocatalytic reaction mechanism of ZnO/Ag₂O.We also studied mechanical chemistry.The plastic deformation behavior of ZnO during the preparation of the reaction was studied in depth.The specific research results of this paper are summarized as follows:1.The Zn?NO₃?₂·6H₂O,AgNO₃,NaOH and the matrix salt NaNO₃ were simply ground by mechanical and chemical methods to synthesize ZnO/Ag₂O.The reaction mechanism of the synthesis process was given.ZnO/Ag₂O was also characterized by SEM,TEM,XRD,FTIR,XPS and EDS.The analysis results show that ZnO/Ag₂O consists of ZnO nanosheets?about several hundred nanometers in diameter?and Ag₂O nanoparticles?about 10 nanometers in diameter?deposited on nanosheets.It has good crystallinity and contains no impurity components.The interval shows a good absorption effectin in visible light.The addition of Ag₂O loading promotes the charge transfer at the interface between the ZnO/Ag₂O heterojunction and improves the separation efficiency of photogenerated carriers.2.The photocatalytic degradation experiments of organic dye solutions under visible light irradiation showed that ZnO/Ag₂O has better photocatalytic activity than pure ZnO and pure Ag2O.With the increase of Ag2O loading,the photocatalytic activity of ZnO/Ag2O is gradually enhanced.When the mass percentage of Ag2O is50%,the photocatalytic activity reaches the optimum value.The photocatalytic stability test of ZnO/Ag₂O with methylene blue showed that ZnO/Ag₂O showed good stability.Combined with photoluminescence?PL?spectroscopy and electron spin resonance?ESR?,we give the reaction mechanism of ZnO/Ag₂O to drive photocatalytic degradation under visible light.Compared with the ZnO/Ag₂O synthesis methods reported in the literature,our mechanical chemistry method has obvious advantages over other methods in synthesizing ZnO/Ag₂O.Our method has the advantages of green,high efficiency and low cost.It exhibits better photocatalytic performance even under visible light.3.The plastic deformation behavior of single crystal ZnO during mechanical chemical preparation was studied.The base surface,prism surface and cone surface of single crystal ZnO hexagonal structure were selected to apply compressive stress,and the Schmid law was used to calculate and analyze.The yield stress of each slip system when single crystal ZnO is subjected to compressive stress,and the slip line in which initial dislocation slip occurs is determined according to the magnitude of the yield stress.It is also found that when the Schmidt factor is 0.5,the single crystal ZnO has a minimum yield stress of 7.2 GPa.4.The mechanical behavior of the catalyst preparation process was analyzed.The ANSYS Workbench finite element software was used for the simulation calculation.The equivalent unit model of ZnO particles based on close packing theory was proposed for the first time.The equivalent unit of ZnO particles under the action of compressive shear force was solved.The density K_t,characteristic stress?_t and characteristic strain?_t of the equivalent unit of ZnO particles are obtained with time.Finally,The mapping relationship between the density Kt,the maximum contact stress distribution Y_ijt,the maximum contact strain distribution E_ijt and the stressed shear state X_t of the equivalent unit of ZnO particles are obtained.Finally,we also give the constitutive relation of the equivalent unit of ZnO particles.