Research On Activity Of Photocatalytic / Photoelectrochemical Water Splitting Of Oxynitrides With Visible Light Response

In order to solve the energy and environmental crisis that humani face, it is important to use the solar energy to produce hydrogen by photocatalytic decomposition of water directly. Most of traditional photocatalyst can only response to UV light, and inproportion of ultrraviolet light in solar ergy spectrum is far less than the visible light, which means it is meaningful to develop the photocatalyst response to visible light.For developing efficient photocatalyst which response to visible light, we preapraed series of xoynitridesby by the method of high temperature solid phase reaction, and characterized, on its photocatalytic properties. The main research work and achievements are as follows:Fistly, in the process of preparation, we investigated the effects of high temperature pretreatment on the formation of TaON and Ta3N5, and foucus on the Preparation conditions of Mg or /and Zr-doped Ta3N5 and BaTaO2 N, and prepared different photoanode material with the FTO glass as substrate by Electrophoretic deposition method.Secondly, the prepared samples were characterized by XRD, UV-Vis and SEM. According to the characterization data, particle size fo TaON and Ta3N5 prepared from Ta2O5 with high temperature pretreatment became large, which indicated that high temperature make contribution to the polymerization of the particle。What’s more,their absorption edge expand to the range of visible light. Absorption edge Mg or/and Zr- doped Ta3N5 and BaTaO2 N showed a blue shift, which means the doping changed the band gap of both of them.Finally, we investigated the photocatalytic activity of the phtoanodes in the three-electrode system. The result showed that the activity of the electrodes whose samples prepared with high temperature pretreatment have an obvious advtange to the electrodes whose sample prepared without pretreatment. Besides, we mordified the photoanodes by post-treatment and loading cocatalyst, the test data told that the activity of the photoanode with post-treatment improved significantly. It may be attribute to the post-treatment play an important role on the separation and migrate of photo-excited electrons and holes,thus improving the photocatalytic activity of the photoanodes. Loading cocatalyst also good for the activity of the phtoanodes.In this paper, we prepared series of oxynitrides by the method of high temperature solid phase reaction, with the relevant data, and confirm the activity of visible response. during the study of the effects of different modification methods on the photocatalytic activity of photoanode materials, and has achieved some positive results, which can provide theoretical basis for the work of future related research.