高比表面Ni-Al复合光催化剂的制备及其活性

摘要

采用水热法制备了不同比例的Ni-Al类水滑石前驱体，焙烧后获得Ni-Al复合金属氧化物。用XRD、SEM、BET和FTIR等技术对样品进行表征。在模拟太阳光下，以降解甲基橙溶液来评价其活性，考察了金属离子比例、焙烧温度等对样品光催化活性的影响。结果表明，当n（Ni）∶n（Al）比为1．5∶1时，焙烧温度400℃时生成了NiO和NiAl2 O4复合氧化物，且其比表面积高达244．82 m2／g。60 min后，0．5 g／L复合光催化剂对浓度为25 mg／L甲基橙溶液的降解率达87．2％。对降解完成后光催化剂红外光谱分析表明，在开灯60 min后甲基橙大分子基本被降解完全。%Ni-Al layered double hydroxides as precursors with different Ni-Al molar ratio were synthesized by hydrothermal method,followed by calcined under suitable temperature to obtain Ni-Al composite metal oxide.The as-obtained samples were characterized by XRD,SEM,BET and FTIR techniques.Its photocat-alytic activities were evaluated by degradation of methyl orange under the irradiation of simulated sun-light.The effects of molar ratio of metal ions and calcination temperature on photocatalytic activity were discussed.The results showed that NiO and NiAl2 O4 composite oxide,with surface area of 244.82 m2/g, were generated when the molar ratio and the calcination temperature were kept at 1 .5∶1 and 400 ℃ re-spectively.The maximum photocatalytic degradation rate of 25 mg/L MO was 87.2%at 0.5 g/L concen-tration of photocatlyst.The photocatalysts after degradation were analyzed by infrared spectrum,almost no undecomposition MO exist within 60 min illumination.