超临界浸渍法制备CuO/Al_2O_3催化剂

Preparation of CuO/Al_2O_3 Catalysts by Supercritical Impregnation

应用超临界浸渍法制备CuO/γ-Al2O3催化剂。以Cu(NO3)2为前驱体,甲醇为助溶剂在载体Al2O3上于超临界二氧化碳中进行浸渍,研究了不同浸渍条件:超临界温度、压力、浸渍时间、前驱体和载体量之比,助溶剂量等因素对浸渍效果的影响。并以SEM和XRD分别对超临界与普通浸渍法制备的样品进行了表征。结果说明,超临界浸渍时吸附速度明显较快,吸附量大,浸渍物分布均匀且和载体作用较强。以亚甲基蓝的催化氧化降解为模型反应测定两种制法催化剂的活性,超临界条件制备的催化剂活性明显较好。所得结果表明,使用无机金属前驱体加助溶剂的方法可以代替有机金属前躯体在超临界浸渍中的使用。

Using impregnation in supercritical fluids, the CuO/γ - Al2O3 catalysts were prepared. Firstly, studies of the absorption of inorganic metal precursor Cu （ NO3 ）2 on Al2O3 carrier in supereritical carbon dioxide with co - solvent CH3 OH were carried out. The effect of catalysts preparation conditions, supereritical temperature, pressure, impregration time, co - solvent, precursor/support ratios, on Cu （ NO3 ）2 adsorption by Al2O3 were investigated. The SEM and XRD were used to examine adsorption property of different catalysts. The results show improved adsorption of Cu （NO3 ）2 on. Al2O3 and enhanced rapid adsorption velocity compare with conventional impregnation. In addition, the distribution of Cu is more uniform and there exists an strong intenaction between Cu and Al2O3. Being a model reaction, the catalytic degradation of methylene blue was investigated in catalysts by supercritical and conventional. The prepared catalysts in supereritical fluids had high activity. It suggests that inorganic metal precursors and co - solvents can replace organometallie precursors in the supercritical impregnation.