Study On Preparation And Modification And Potoelectrocatalysis Of TiO₂

Photoelectrocatalysis can be used to mineralize hazardous substances completely, while the other wastewater treatment techniques can not do so. Photoelectrocatalysis has the good values of application and promotion in the field of wastewater treatment.TiO₂ powder was prepared by sol-gel method firstly, and the preparation conditions werer optimized by the orthogonal experiments. The main factors which affected the gelation process and catalytic capability were discussed. Then TiO₂-AC powder was prepared by sol-gel method too. The amount of reagents including anhydrous ethanol, distilled water, nitric acid, activated carbon and calcination temperature were optimized, and the optimum preparation conditions were obtained. After that, TiO₂-AC-PTFE photoanode was prepared using TiO₂-AC and PTFE as the catalyst and the binder, respectively. The photoanode has an excellent photoeletrocatalytic property. The adsorption, photo-catalysis, electric and photoelectric properties of the photoanode were investigated using phenol solution as a pollutant. The parameters influencing the photoelectrocatalytic efficiency such as current density, cathode material, pH and the initial concentration of phenol were discussed.Photoelectro-Fenton can degrade phenol effectively when the TiO₂-AC-PTFE was used as the anode and the oxygen diffusion electrode as the cathode.The results showed that the good adsorption property of photoanode could improve the removal efficiency greatly. The combination of photocatalysis and electrocatalysis had an obvious synergetic effect and the acidic condition is optimum.The photoanode was prepared successfully, this research not only solved the troubles of reclaimation of suspended catalyst, but also achieved the combination of photocatalytic and electro-catalytic, so the efficiency of wastewater treatment was improved.TiO₂ powder was modified by the doping of Co2+, Co3+ and [Co(NH3)6] 3+ in this work. The results indicated that Co2+ doping can not improve the photocatalytic performance of TiO₂ powder, and Co3+ could not exist stably in acidic solution, so it does not work on improving the photocatalytic performance of TiO₂ powder. However, [Co(NH3)6]3+ can contribute to improve the capability of TiO₂ powder.