氮修饰ZnO/ZnAl2O4复合光催化剂及其活性

以硝酸锌和硝酸铝为原料,采用共沉淀法制备了纳米异质结ZnO/ZnAl2O4复合光催化剂.用不同氮源经固相混合焙烧对样品进一步修饰,通过 XRD、SEM、HRTEM、TG-DTA和BET等手段对样品进行了表征.结果表明样品是由ZnO与ZnAl2O4两相组成,平均粒径约为15～20 nm,最佳焙烧温度下的比表面为54.81 m2/g.在模拟太阳光照射下,以甲基橙溶液的光催化降解考察样品的光催化活性.研究了Zn/Al物质的量比,氮源和掺氮量,样品焙烧温度等对光催化降解活性的影响.实验表明,当Zn/Al物质的量之比为1：1.5,六次亚甲基四胺（HMT）作为氮源且与ZnO/ZnAl2O4质量比为1：3混合时,所得样品经600℃焙烧后具有最佳光催化活性.当光催化剂用量为0.5 g/L,用模拟太阳光照射60 min后,对浓度为25 mg/L甲基橙溶液的脱色率为91%.

Preparation and Photocatalytic Activity of ZnO/ZnAl2O4 Modified by N-doped

ZnO/ZnAl2O4 nanocomposites with heteronanostructures were successfully prepared by coprecipitation method using zinc nitrate and aluminum nitrate as raw materials.The sample was further modified with different nitrogen source by solid state method. The as-prepared samples were characterized by XRD, SEM, HRTEM, TG-DTA and BET techniques. The results indicate that the sample particle sizes are in the range of 15～20 nm, and the BET of 55.92 m2/g, which consists of ZnO and ZnAl2O4. The photocatalytic activities of the as-prepared samples were evaluated by the photocatalytic degradation of methyl orange under the irradiation of the simulated sunlight. The effects of the molar ratio of Zn to Al, type of nitrogen source, N -doping content, and annealing temperatures on the photocatalytic activities were studied. The results showed that the optimum photocatalytic activity was observed at the starting Zn to Al molar ratio of 1：1.5, using HMT as nitrogen source, the mass ratio of HMT to ZnO/ZnAl2O4 of 1：3 in the mix materials and calcination temperature of 600℃ , the maximum photocatalytic decoloration rate of 91% within 60 min was obtained at 0.5 g/L concentration under the irradiation of the simulated sunlight.