Preparation And Performance Of Nonmetal Doped-nanocrystalline TiO₂ Photocatalyst

Using tetrabutyl titanate?Ti?OC₄H₉?₄? as titanium source, anhydrous ethanol?EtOH? as solvent, acetic acid as hydrolysis inhibitor, and nitrogen compounds with poor thermal stability as solid carrier, A new type of sol-gel method were applied to prepare visible light responsed nonmetal doping nano TiO₂ photocatalysts. The preparated samples were characterized by power X-ray diffraction?XRD?, transmission electron microscopy?TEM?, nitrogen adsorption desorption, X-ray electron energy spectrum scanning?XPS? and UV-Vis diffuse reflection?UV-Vis DRS?. The photocatalytic performances of samples were investigated with metal halide lamp as visible light?high pressure mercury lamp as ultraviolet light? and rhodamine B?RB? as simulation of pollutant, and the influences to its composition, structure, and performance in different mole ratio of dopant materials and different calcination temperature were analyzed.?1? Nitrogen doping nano TiO₂ catalysts?N-TiO₂?were prepared by using ammonium nitrate as the nitrogen doping source and solid carrier. When the mole ratio of Ti?OC₄H₉?₄ and NH₄NO₃ was 2, the dry gel was heat treated under 200 ?, the prepared nitrogen doping TiO₂ catalyst had uniform particles, small size, large specific surface area and pore volume, and its band structure was adjusted, light absorption edge was expanded to about 414 nm. The degradation rate of RB after 45 min has reached 90% under visible light irradiation, which was obviously better than that of p25?standard TiO₂?.?2? with ammonium chloride as the doping source and solid carrier,nitrogen and chlorine co-doped TiO₂ catalysts?N-Cl-TiO₂? were prepared, and the catalytic degradation efficiency of these samples under visible light irradiation were very high. When the mole ratio of Ti?OC₄H₉?₄ and NH₄ Cl was 3, the calcined temperature was 200 ?, the prepared nitrogen and chlorine co-doped TiO₂ catalyst had large specific surface area and pore volume, and its light absorption edge appeared to a obvious red shift compared to p25, of which the photocatalytic degradation performance was best. Its degradation rate of RB under visible light reached 90% after 60 min, which was better than that of p25.?3? carbon, nitrogen and sulfur co-doped nanoTiO₂ catalysts?C-N-S-TiO₂? were prepared with thiourea as doping source and solid carrier. The results showed that when the mole ratio of Ti?OC₄H₉?₄ and N₂H₄ CS was 2, dry gel was calcined under 450 ?, the prepared sample has uniform particle and good dispersibility. Its light absorption edge had a certain degree red shift relative to pure TiO₂. Under visible light irradiation, the photocatalytic degradation rate of RB is 94% after 90 min which was higher than under ultraviolet irradiation, and the degradation rate is 43% higher than that of pure TiO₂.