Preparation and characterization of Mo-N-TiO2 photocatalyst activity enhanced-mechanism
Mo-N-TiO2光催化剂的制备、表征及其活性提高机制

Mo-N-codoped TiO2 nanoparticles were synthesiezed by a sol-gel method using ammonium molybdate and ammonia water as the Mo source and N source,respectively.The resulting materials were characterized by XRD,XPS and UV-vis DRS.XRD showed that doping with Mo and N could effectively restrain the growth of crystallite and enhance the temperature of phase transformation from anatase to brookite.The UV-vis DRS results showed that the light absorption edge was extended to visible light region.Moreover,the modified TiO2 with 0.5% ammonium molybdate doping amount exhibited the largest photoresponse with its absorption edge shifting to 550 nm.XPS analysis displayed that Mo existing as cationic Mo6+ by replacing Ti4+ and the structure of nitrogen was unsymmetric which could be attributed to the formation of O—Ti—N and Ti—N.The effects of calcination temperature and ammonium molybdate doping amount on the simulated sunlight photocatalytic performance of modifed TiO2 for degrading RhB were investigated.It was found that the Mo-N-TiO2 calcined at 400℃ with 0.5% ammonium molybdate doping amount exhibited the highest photocatalytic performance.Under the simulated sunlight irradiation with 120 min,the 96.8% degradation rate of RhB could be achieved,which was 2.42 times to that of pure TiO2.