【作者】 王万领；

【导师】 张伟风； 李国强；

【作者基本信息】 河南大学 ， 凝聚态物理， 2011， 硕士

【摘要】 自1972年本多和藤岛报道了“本多--藤岛效应”以来,多相半导体光催化的研究以其在治理污染和氢能制备方面的应用引起了广泛关注。传统的二氧化钛光催化剂,以无毒、性能稳定、廉价等优点已得到广泛应用。但是,由于其带隙较宽,不能利用可见光,限制了其对太阳光的利用。为了更多的利用太阳能,开发可见光响应的光催化材料成为光催化利用的一个研究热点。含Ag金属氧化物半导体材料是一类可见光响应的光催化材料。锑酸银和铌酸银带隙分别是2.6 eV和2.8 eV,都能利用可见光,并且具有光催化性能。本文通过成分控制、合成方法以及形成复合材料的形式制备了样品,并且研究了其表面光电性能和光催化性能。具体的研究工作如下1)通过离子交换法制备了具有不同Ag/Sb锑酸银。首先通过AgNO₃和H₂Sb₂O₆·nH₂O反应制备了前躯体Ag_xH_ySb₂O₆·nH₂O,然后在700 oC煅烧1小时,得到不同组分的锑酸银（Ag_xSb₂O_y:x=0.5,y=4.83;x=1.0,y=5.18;x=1.5,y=5.52;x=1.7,y=5.77）样品。利用X射线衍射仪、紫外可见分光光度计、拉曼散射光谱仪、扫描电子显微镜和表面光电压谱仪,表征了其物相组成,表面形貌,表面光电特性。通过光催化降解罗丹明B（RhB）评价了其光催化性能。结果显示随着在锑酸银中Ag/Sb的增加,光学带隙减小,表面光电压减小,对RhB的光催化降解性能增强;同时,表面光电压和光催化性能受样品中的+3价锑离子的含量调制:随着正三价锑的含量减小,光催化性能逐渐增加。2)采用溶剂热法在不同温度下（170-240 oC）制备了的铌酸银（AN170, AN180, AN190, AN200, AN240）样品。首先在100 mL的反应釜中加入适量的乙二醇,硝酸银和五氯化铌,接着在不同温度的干燥箱中反应24小时。然后把得到的先驱体在800 oC煅烧2小时,得到铌酸银样品。利用X射线衍射仪、紫外可见分光光度计、拉曼散射光谱仪、扫描电子显微镜和表面光电压谱仪,表征了其物相组成,表面形貌,表面光电特性。通过光催化降解罗丹明B（RhB）评价了其光催化性能。结果表明:样品不同形貌的形成可能归因于不同的银颗粒造成的;AN190样品具有最高的光催化性能和最弱的表面光电压,可能归因于铌酸银和五氧化二铌的协同作用。温度的选择和五氧化二铌的量对于形貌的形成和样品的性质起着关键的作用。3)采用固相法制备了不同摩尔比的锑酸银与铌酸钠的复合物。首先把适量的Ag₂O,Sb₂O₃和Na₂CO₃,Nb₂O₅分别按一定的摩尔比混合均匀,依次在750和900 oC分别煅烧4小时和8小时,得到锑酸银与铌酸钠的复合物（xAgSbO₃/NaNO₃, x=0.5、1.0、2.0、4.0、6.0）样品。利用X射线衍射仪、紫外可见分光光度计、拉曼散射光谱仪、扫描电子显微镜和表面光电压谱仪,表征了其物相组成,表面形貌,表面光电特性。通过光催化降解罗丹明B（RhB）评价了其光催化性能。结果表明:样品的表面光电压和光催化活性对锑酸银的含量敏感。铌酸钠与锑酸银的摩尔比是1:1时的复合物具有最高的光催化活性,这一点归因于它的良好的分散性,电子传输和表面光电特性。这些结果表明制备良好的复合物来修饰催化剂的光物理和光化学特性是一种有效的方法。更多还原

【Abstract】 Multiphase semiconductor photocatalysis, the problems of the pollution and preparation of hydrogen have been paid wide attention since Fuji and Shima reported“Honda-Fujishima Effect”. Traditional photocatalysis, TiO₂ with non-toxic, stable performance and low-cost price has been widely applied. But, titanium dioxide is not able to absorb visible light due to its wide band gap, in order to make full use of solar energy, developing photoctalysis in visible region has been one of numerous research focuses in photocatalytic field.Silver oxide semiconductor is a type of photocatalysis material with responding to visible light. Silver antimonite with band gap of 2.6 eV and silver niobate with band gap of 2.8 eV not only absorb visible light but only possess photocatalytic property. In this work, samples were prepared by controlling composition, prepared methods and formation of composite materials. Surface photovoltaic and photocatalytic properties of samples were researched. The specific research work is as follows:1) Silver antimonite with different molar ratio of Ag/Sb were prepared by an ion change method. Firstly, Ag_xH_ySb₂O₆·nH₂O were prepared by the ion exchange of AgNO₃ and H₂Sb₂O₆·nH₂O, and were calcined at 700 oC for 1 hour, in result that the samples of Ag_xSb₂O_y （x=0.5,y=4.83;x=1.0,y=5.18;x=1.5,y=5.52;x=1.7,y=5.77） were obtained. Their phases, surface morphology and surface photovoltaic property were characterized by X-ray diffraction, UV-visible spectrophotometer, Raman scattering, scanning electron microscopy and surface photovoltage spectroscopy, respectively. The photocatalytic property was estimated by degradation of Rhodamine B. The results show that the optical band gap decreases, the surface photovoltage decreases and the photocatalytic activity for Rhodamine B decomposition increases with increasing the Ag/Sb ratio in silver antimonites. The surface photovoltaic and photocatalytic properties were impacted by the percent of Sb³⁺ in the samples. The photocatalytic activity variation with the amount of Sb3+ implies that appropriate amount of Sb³⁺ in the sample was favorable for photocatalytic activity.2) Silver niobate was prepared by a solvothermal method at different temperatures （170-240 oC）. Firstly, approppriate amount of EG, silver nitrate and columbium pentachloride are put into 100 mL reactor,then react for 24 hours at different temperatures. Last, the precursor is calcained for 2 hours at 800 oC, in result samples of AN170, AN180, AN190, AN200 and AN240 are obtained. Their phases, surface morphology and surface photovoltaic property were characterized by X-ray diffraction, UV-visible spectrophotometer, Raman scattering, scanning electron microscopy and surface photovoltage spectroscopy. The photocatalytic property was estimated by degradation of Rhodamine B. The results show that different morphologies may be due to different morphologies of Ag particles and that AN190 with the weakest photovoltage and the highest photocatalytic activity may be due to synergetic effect between silver niobate and Nb2O5. Both the temperature and the amount of Nb₂O₅ are crucial for the morphologies, the photoelectric and photocatalytic properties of the samples.3) The compound with different molar ratio of silver niobium and sodium antimony were prepared by solid state reaction method. Firstly, appropriate amount Ag₂O,Sb₂O₃, Na₂CO₃ and Nb₂O₅ were well mixed respectively, then are calcained at 750 oC for 4 hours and 900 oC for 8 hours in turn. The samples of xAgSbO3/NaNO3 （x=0.5, 1.0, 2.0, 4.0, 6.0）are obtained. Their phases, surface morphology and surface photovoltaic property were characterized by X-ray diffraction, UV-visible spectrophotometer, Raman scattering, scanning electron microscopy and surface photovoltage spectroscopy. The photocatalytic property is estimated by degradation of Rhodamine B. The results show that the surface photovoltage and photocatalytic activities were sensitive to the molar percentage of sodium antimony in the samples; the highest photocatalytic activity was observed on the composite of silver niobium and sodium antimony due to the better dispersiveness, electron transfer and surface photoelectric properties, these results indicate that making the composite is an effective method to modify the photophysical and photochemical properties of photocatalyst.更多还原