镍离子表面处理对二氧化钛光催化活性的影响

采用溶胶-凝胶法制备出纳米TiO2和TiO2-Ni催化剂. 光催化降解对氯苯酚实验证明, TiO2-Ni催化剂的紫外、可见光催化活性均高于TiO2. FTIR和Raman结果表明, Ni2+离子被化学吸附在TiO2表面形成ONiOO表面物种. SPS的结果表明, TiO2-Ni表面ONiOO物种的表面态能级在价带上方2.84 eV. 该能级既能产生可见光响应, 又有效地促进了光生载流子的分离, 使催化剂紫外、可见光催化活性提高.

Effect of Surface Modification by Ni2+ on Photocatalysis Activity of TiO2

Sol-gel process was employed to prepare TiO2 and nickle-modified TiO2 powders. Photodegradation of 4-chlorophenol was employed to evaluate the photocatalytic activities of the catalysts. Compared to TiO2, nickle-modified TiO2 exhibited improved activity for degradation of 4-chlorophenol under both ultraviolet and visible light irradiations. The properties of these catalysts were investigated with X-ray diffraction (XRD), diffuse reflectance UV-Vis spectra, infrared spectra (IR), Raman spectra, and surface photovoltage spectroscopy (SPS). We found that Ni2+ was chemisorbed on the surface of TiO2 and formed ONiOO, which introduced the energy level of surface states 2.84 eV above the valence band. This energy level not only generated response to visible light but also promoted the separation of photogenerated carriers. Thus, the activity under ultraviolet and visible light irradiations was increased.