Sonochemical Synthesis Of Zn₃V₂O₇（OH）₂（H₂O）₂ And The Theoretical Studies Of Zn₃V₂O₇（OH）₂（H₂O）₂ Photocatalys

In recent years, the photocatalytic degradation of organic compounds has attracted worldwide attention, because the photocatalysts can decompose the organic pollutants into harmless small molecules completely. Developing novel photocatalysts with high activity is very important for widely application. Solvent thermal method, water bath method and hydrothermal method had been already used for the synthesis of nanomaterials. In this study we provided an unusual route which was ultrasound method to synthesize Zn3V2O7(OH)2(H2O)2 nanocrystalline, and the activity of the photocatalysts were systematically investigated.At the beginning of this study, we used hydrothermal method to synthesize Zn3V2O7(OH)2(H2O)2 nanocrystalline while the temperature was 70℃ and the reaction time was 20 hours. Successfully,we synthesized Zn3V2O7(OH)2(H2O)2 nanocrystalline with flower-like morphology was synthesized successfully.The photocatalytic activities of the as-prepared samples were evaluated by the degradation of Methylene Blue (MB) under UV light irradiation.The results showed that Zn3V2O7(OH)2(H2O)2 nanocrystalline exhibited the highest activity when the pH value of reaction liquid is 5. Significantly,Zn3V2O7(OH)2(H2O)2 nanocrystalline were synthesized by ultrasound method while the reactants were Zn(NO3)2, NaVO3 and Na(OH).Using ultrasound method to synthesize nanomaterials, we need not to provide bulk high temperatures, high pressures, or long reaction time.We explored the effects of samples under different reaction times and pH value. In conclusion, Zn3V2O7(OH)2(H2O)2 nanocrystalline with high activity when reaction time was 5 hours and the pH value of reaction liquid was 5. The reason was that Zn3V2O7(OH)2(H2O)2 nanocrystalline grew along different direction with different pH value.Crystal structure of the samples grew preferentially along the [102] direction while lagging along the [110] direction.We speculate that the planes grew along [102] direction could be the active planes of Zn3V2O7(OH)2(H2O)2 nanocrystalline.C3N4 and Zn3V2O7(OH)2(H7O)2 were mixed together to synthesize H2O)2 nanocrystalline by ultrasound method. With adding contents, the absorption edge of samples had a clear red shift reaching 420nm, which could be responsible for the visible-light induced photocatalytic activities.The degradation experiment of MB shows that C3N4/Zn3V2O7(OH)2(H2O)2 can be used as a photocatalyst under visible light irradiation.