络合剂对溶胶凝胶制备纳米铜及其催化性能影响

摘要

To study the influence of complexing agents on the preparation and catalytic performance of nano⁃copper in sol⁃gel method, the preparation of nano⁃copper powders was carried out by sol⁃gel method using citric acid and glucose as complexing agents, respectively. The influence of complexing agents on the process and product structure was studied. In addition, the catalytic performance of nano⁃copper powders obtained using the two complexing agents were also investigated for the oxidation reaction of benzene to phenol. Results showed that the nano⁃copper powder prepared with glucose( G-Cu) possessed smaller mean grain size of 30 nm and smaller specific surface area of 5.203 m2/g than that of citric acid(C-Cu) (55 nm and 19.517 m2/g, respectively). For oxidation reaction, G-Cu displayed higher benzene conversion(50.30%), but bad selectivity of phenol. While C-Cu showed lower benzene conversion(21.95%) and higher selectivity of phenol(38.46%). Furthermore, it was found that copper ions were coordinated with carboxyl and hydroxyl for citric acid and glucose respectively.%为研究络合剂对纳米铜粉体的制备及其催化性能的影响，分别以柠檬酸、葡萄糖为络合剂，采用溶胶－凝胶法制备纳米铜．考察了两种络合剂对制备过程以及产物结构的影响，通过催化苯氧化合成苯酚的反应考察制得的纳米铜粉的催化性能．研究表明：葡萄糖为络合剂制得的纳米铜（G－Cu）平均粒径较小（30 nm），比表面积为5．203 m2／g，在催化苯制苯酚反应时，具有较高的苯转化率（50．30％），但对苯酚的选择性较差；而柠檬酸为络合剂制得的纳米铜（C－Cu）平均粒径为55 nm，比表面积19．517 m2／g，催化苯转化率为21．95％，选择性为38．46％．此外，通过对溶胶凝胶法制备机理分析可知，在形成的胶体结构中，柠檬酸和葡萄糖中的羧基和羟基分别与铜离子进行配位．