(湖南理工学院 化学化工学院，岳阳 414006)
摘 要: 采用一步水热法制备ZnO/ZnAl2O4复合光催化剂前驱体。用不同量的磷酸溶液通过浸渍蒸干法对样品进行修饰，并于不同温度下焙烧获得高活性ZnO/ZnAl2O4纳米复合光催化剂。采用XRD、SEM、TEM、BET和TG-DTA 等技术对所得样品进行表征。在模拟太阳光下，以光催化降解甲基橙和还原CO2评价样品的光催化活性，并考察磷酸修饰量、样品焙烧温度对光催化活性的影响。结果表明：磷酸修饰可提高样品的高温稳定性、晶化程度及比表面积。当磷酸修饰量为n(Zn):n(P)为100:2.0时，经500 ℃焙烧后所得样品的光催化活性最佳。当光催化剂用量为0.5 g/L时，在60 min内对25 mg/L甲基橙溶液的脱色率达到98%，较未修饰样品的提高15.3%。对最佳条件下所得样品进行CO2光催化还原，当催化剂用量为1.0 g/L、反应6 h后，所得还原产物中甲醇的生成量为1.60 mmol/g。
关键字: ZnO/ZnAl2O4；磷酸修饰；光催化活性；催化剂
（School of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China）
Abstract:ZnO/ZnAl2O4 precursor was synthesized by one-pot hydrothermal method. Phosphoric acid (H3PO4) was loaded on the precursor by an impregnation and steam seasoning process to obtain ZnO/ZnAl2O4 composite photocatalyst with high photocatalytic activity after calcination. The as-prepared samples were characterized by XRD, SEM, TEM, BET and TG-DTA techniques. The photocatalytic activities of the samples were evaluated by degradation of methyl orange (MO) and reduction of CO2 under the simulated sunlight irradiation. The effects of the amount of H3PO4 modification and calcinations temperature on the photocatalytic activities of the samples were investigated. The results indicate that H3PO4 modification improves the high temperature stability, degree of crystallization and specific surface area of the samples. The maximum of 98% photocatalytic decoloration rate of MO is achieved within 60 min at 0.5 g/L concentration of sample obtained at the mole ratio of Zn to P 100:2 and the calcination temperature of 500 ℃, which increases by 15.3% compared to that of bare ZnO/ZnAl2O4. Meanwhile, the main reduction products, methanol, the maximum yield of 1.60 mmol/g within 6 h is obtained at 1.0 g/L concentration of the same sample.
Key words: ZnO/ZnAl2O4; H3PO4 modification; photocatalytic activity; catalyst
