Nanosized TiO2-SiO2 supported catalysts were prepared by low-temperature hydrothermal method.These catalysts were characterized by BET,XRD,and employed to degrade methylene blue under UV-irradiation.The results show t...Nanosized TiO2-SiO2 supported catalysts were prepared by low-temperature hydrothermal method.These catalysts were characterized by BET,XRD,and employed to degrade methylene blue under UV-irradiation.The results show that hydrothermal time and TiO2 content have critical effect on performance of the catalysts.The catalyst prepared with TiO2-SiO2 ratio of 7:3 and hydrothermal time of 5 h exhibited the highest photoactivity of 0.0307 min-1,which was 2 times higher than that of pure TiO2.This strongly indicated that the photocatalytic activity of titania/silica mixed materials depends on the adsorption ability of catalyst and the photocatalytic activity of the titania,and there is an optimal ratio of Ti : Si,too high or low Ti : Si ratio will lower the photodegradation ability of the catalysts.展开更多
以二水合醋酸锌和三乙醇胺(TEA)为原材料,利用相对低温的水热法制备多种形貌、大尺寸的ZnO颗粒。通过X线衍射仪(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)和紫外可见光吸收光谱仪(UV Vis)对制备的样品进行表征。考察TEA用量、醋...以二水合醋酸锌和三乙醇胺(TEA)为原材料,利用相对低温的水热法制备多种形貌、大尺寸的ZnO颗粒。通过X线衍射仪(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)和紫外可见光吸收光谱仪(UV Vis)对制备的样品进行表征。考察TEA用量、醋酸锌浓度、反应温度以及反应时间对ZnO形貌的影响,并讨论ZnO的生长机制。结果表明:制备的产物均为具有六方晶系纤锌矿结构的ZnO。取0.006 mol/L的TEA 0.25、0.5、1、1.5和2 m L,分别加入4 m L 0.8 mol/L醋酸锌溶液中,100℃水热反应8 h,对应合成了短六棱柱、六棱柱、纺锤状、双六棱锥及六棱锥状ZnO(长约8μm,底面直径约5μm)。醋酸锌浓度为0.4 mol/L时,加入2 m L TEA,100℃水热反应8h制得平均粒径为4μm的ZnO微球。在4 m L 0.8 mol/L醋酸锌溶液和1 m L TEA情况下,反应温度低于100℃时,合成的ZnO不具有孪晶结构;水热反应时间达到8 h制得的ZnO才具有良好结晶度。考察了不同形貌ZnO光降解亚甲基蓝的活性,发现双六棱锥形貌ZnO的紫外可见光吸收有蓝移现象,也表现出更好的光活性。展开更多
文摘Nanosized TiO2-SiO2 supported catalysts were prepared by low-temperature hydrothermal method.These catalysts were characterized by BET,XRD,and employed to degrade methylene blue under UV-irradiation.The results show that hydrothermal time and TiO2 content have critical effect on performance of the catalysts.The catalyst prepared with TiO2-SiO2 ratio of 7:3 and hydrothermal time of 5 h exhibited the highest photoactivity of 0.0307 min-1,which was 2 times higher than that of pure TiO2.This strongly indicated that the photocatalytic activity of titania/silica mixed materials depends on the adsorption ability of catalyst and the photocatalytic activity of the titania,and there is an optimal ratio of Ti : Si,too high or low Ti : Si ratio will lower the photodegradation ability of the catalysts.
文摘以二水合醋酸锌和三乙醇胺(TEA)为原材料,利用相对低温的水热法制备多种形貌、大尺寸的ZnO颗粒。通过X线衍射仪(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)和紫外可见光吸收光谱仪(UV Vis)对制备的样品进行表征。考察TEA用量、醋酸锌浓度、反应温度以及反应时间对ZnO形貌的影响,并讨论ZnO的生长机制。结果表明:制备的产物均为具有六方晶系纤锌矿结构的ZnO。取0.006 mol/L的TEA 0.25、0.5、1、1.5和2 m L,分别加入4 m L 0.8 mol/L醋酸锌溶液中,100℃水热反应8 h,对应合成了短六棱柱、六棱柱、纺锤状、双六棱锥及六棱锥状ZnO(长约8μm,底面直径约5μm)。醋酸锌浓度为0.4 mol/L时,加入2 m L TEA,100℃水热反应8h制得平均粒径为4μm的ZnO微球。在4 m L 0.8 mol/L醋酸锌溶液和1 m L TEA情况下,反应温度低于100℃时,合成的ZnO不具有孪晶结构;水热反应时间达到8 h制得的ZnO才具有良好结晶度。考察了不同形貌ZnO光降解亚甲基蓝的活性,发现双六棱锥形貌ZnO的紫外可见光吸收有蓝移现象,也表现出更好的光活性。
