【作者】 王威；

【导师】 徐君莉；

【作者基本信息】 东北大学 ， 应用化学， 2015， 硕士

【摘要】 环境污染和能源危机是人们亟待解决的两大课题。光催化技术具有反应条件温和、可减少二次污染、效率高、能耗低等优点,以ZnO、TiO2等半导体氧化物为代表的光催化材料越来越引起人们的重视。本论文研究了 ZnSe/ZnO复合材料的制备及其光催化性能。采用化学腐蚀法制备纳米ZnO,应用扫描电镜(SEM)、X-射线衍射(XRD)、拉曼光谱(Raman Spectra)对其进行了表征,并以甲基橙、酸性蓝1和罗丹明B为降解对象,考察了ZnO纳米材料对染料的可见光催化降解性能。结果表明,H2S04的浓度可以影响生成的ZnO的结构。1.67 mol/L和1.15mol/L H2SO4水溶液腐蚀3 min在锌基体上得到花瓣状的纳米片,而3.07 mol/L H2S04水溶液腐蚀得到ZnO纳米颗粒。相对于ZnO纳米颗粒,花瓣状的ZnO纳米材料在降解甲基橙反应中表现有更高的降解效率。ZnO纳米片在降解甲基橙和酸性蓝方面具有不错的降解效率,在可见光下降解甲基橙90min,甲基橙几乎完全降解。然而制备的ZnO具有较差的光稳定性。第二次循环的的降解效率降低到40%,五次循环之后几乎不具备任何光催化活性。同时,采用电化学方法制备了纳米ZnO,应用扫描电镜(SEM)、X-射线衍射(XRD)对其进行表征,同时考察了沉积电位和沉积时间对ZnO纳米材料的结构及其光催化性能的影响。结果表明,不同电极可以影响生成的ZnO的结构及其光催化性能。相同的条件下,阳极氧化得到颗粒状ZnO纳米材料,而阴极沉积得到剑状的ZnO纳米材料。阴极沉积得到的剑状ZnO纳米材料3 h对甲基橙的可见光催化效率为60%,而氧化时间是1.5 h、氧化电位是10 V下氧化得到的颗粒状ZnO纳米材料的光催化降解能力最强,4 h对甲基橙的紫外光催化降解效率为90%。另外,采用电化学沉积法在不同基体上制备了 ZnSe薄膜,应用扫描电镜(SEM)、X-射线衍射(XRD)、拉曼光谱(Raman Spectra)进行表征,并考察了基体、沉积电位、沉积时间等因素对薄膜成分及其结构的影响,及其光催化性能。结果表明,基体对沉积的物相成分和形貌有较大的影响。Zn基体比Cu基体更有利于ZnSe的形成。不同沉积电位下制备的ZnSe,其光催化降解甲基橙的性能有较大的区别。在-0.6 V下恒电位沉积2 h得到的ZnSe薄膜降解效率最高,降解效率达到90%,并分析了影响其光催化性能的主要因素。结合化学腐蚀和电沉积法制备ZnSe/ZnO复合纳米材料。应用扫描电镜(SEM)、X-射线衍射(XRD)对复合光催化剂的结构进行表征,并考察了其光催化性能。结果表明,ZnSe/ZnO复合纳米材料具有很好的光催化性能,其对甲基橙的可见光降解,在80分钟时降解效率达到95%。ZnSe/ZnO复合结构有助于光生电子和空穴对的分离,降低其复合机率,从而具有较高的光催化效率。更多还原

【Abstract】 Environmental pollution and energy crisis are two serious problems.The photocatalytic materials based on ZnO,TiO2 and the other semiconductor oxides have been attracted much attention due to moderate reaction condition,lower secondary pollution,high efficiency and low energy consumption.In this dissertation,ZnSe/ZnO composite materials were prepared and their photocatalytic properties were studied.Nanostructure ZnO was prepared through a simple chemical corrosion process,and it was characterized by scanning electron microscopy,X-ray diffraction and Raman spectra measurement techniques.The prepared nanostructure ZnO was used to investigate the degradation of dye including methyl orange,acid blue and rhodamine B under visible light irradiation.The results show that the microstructure of the obtained ZnO depends on the concentration of H2SO4.Flower-like structures consisting of nanosheets are obtained on zinc plate by 4 min corrosion in 1.67 mol/L and 1.15 mol/L H2SO4 solutions,while nano size ZnO particles are obtained in 3.07 mol/L H2SO4 solution.The flower-like nanostructure ZnO is more effective on the degradation of methyl orange than ZnO nanoparticles.ZnO nanosheets present good degradation on methyl orange and acid blue.Methyl orange is almost completely degraded by ZnO nanosheets in 90 min under visible light irradiation.However,the obtained ZnO exhibits poor photostability.The decomposition ratio decreases to 40%for the second cycle,and it doesn’t present any photocatalytic activity after five cycles.Nanostructure ZnO was prepared by electrochemical method,and it was characterized by scanning electron microscopy,X-ray diffraction measurement techniques.The deposition potential and time on the structure and the photocatalytic properties of films were studied systematically.The results show that the microstructure of the obtained ZnO depends on different electrode.The sword-like nanostructure ZnO is obtained on cathode,while ZnO nanoparticles are obtained on anode under the same condition.ZnO prepared on cathode with deposition time of 3 h shows the highest degradation efficiency under visible light,and 60%methyl orange is degradated in 3 h.The sword-like ZnO nanostructure materials which are prepared on anode with anodic time of 1.5 h and anodic potential of 10 V showed the highest degradation efficiency under ultraviolet light,and 90%methyl orange could be degradated in 4 h.ZnSe films were prepared by electrochemical deposition method,and they were characterized by scanning electron microscopy,X-ray diffraction and Raman spectra measurement techniques.The effects of substrate,deposition potential and time on the composition and structure of films were studied systematically.The photocatalytic properties of these films were also studied.The results show that the substrate has a great influence on the phase composition and morphology of films.Zn substrate is beneficial to prepare ZnSe films.Moreover,the films prepared under the various potentials present different photodegradation rates on methyl orange.The film which is prepared under the potential of-0.6 V with a deposition time of 2 h shows the highest degradation efficiency and 90%methyl orange could be degradated in 6 h.The factors which influence photocatalytic activities are also discussed.ZnSe/ZnO nanocomposites were prepared by the combination of chemical corrosion and electrodeposition methods,and the prepared ZnSe/ZnO nanocomposites were characterized by scanning electron microscopy and X-ray diffraction.The results show that the as-grown ZnSe/ZnO nanocomposites show high degradation efficiency,and 95%methyl orange could be degradated in 80 minutes.The combination of ZnO and ZnSe are good for sperating photogenerated electrons from holes,reducing the composite probability,thereby improving the photocatalytic properties of nanostructure ZnSe/ZnO.更多还原