采用NH3-H2气氛两步热处理法制备氮掺杂-氧缺陷TiO2,用x射线粉末衍射、N2吸附BET法、X射线光电子能谱、元素分析、电子自旋共振谱、紫外-可见漫反射光谱和荧光光谱等技术对样品的晶相结构、表面化学状态、氮含量、氧缺陷位种类及含量、光吸收性能和光生载流子的分离效率等性质进行了表征,研究了H2气氛中不同热处理时间对催化剂性能的影响和催化剂样品在可见光(λ＞ 400 nm)条件下的光催化氧化能力.结果表明,掺氮TiO2催化剂经H2热处理1h后具有较好的可见光催化活性,对苯的转化率和矿化率分别为66.8％和47.5％,其降解效率高于单掺杂催化剂活性的总和,双掺杂光催化剂活性的提高与氮杂质-氧缺陷双光活性中心的协同增强作用有关.
N-doped and oxygen-deficient titanium dioxide was synthesized by heating TiO2 in NH3 atmosphere,followed by the post-calcination in H2 for different time.The physicochemical properties of the products were characterized by X-ray diffraction (XRD),N2-sorption BET surface area,X-ray photoelectron spectroscopy (XPS),elemental analysis (EA),electron spin resonance (ESR),UV-vis diffuse reflectance spectrum (UV-vis DRS) and photoluminescence spectrum (PL).The photocatalytic activity of catalysts was determined by the degradation of gas-phase benzene under visible light (λ ＞ 400 nm) irradiation.Effect of the H2 heat-treatment on the photocatalytic performance of the as-prepared catalysts was investigated.The results show that the N-doped TiO2 post-heated in H2 atmosphere for 1 h exhibited the high photocatalytic activity.After photocatalytic oxidation for 5 h,the conversion rate and mineralization rate of benzene over the co-doped catalyst are up to 66.8％ and 47.5％,respectively.The photocatalytic activity of the co-doped catalyst is much higher than that of the sums on N-doped TiO2 and oxygen-deficient TiO2.The enhanced photoactivity of the co-doped catalysts is related to a synergistic effect of N dopants and the oxygen vacancies in TiO2 lattice.
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