甲醇脱氢制无水甲醛的高活性Ag-SiO_2-Al_2O_3催化剂

Highly Active Ag-SiO_2-Al_2O_3 Catalyst Used for the Dehydrogenation of Methanol to Anhydrous Formaldehyde

采用溶胶 -凝胶法制备了甲醇直接脱氢制无水甲醛的新型高活性催化剂Ag SiO2 Al2 O3 ,并考察了银负载量、焙烧温度及反应温度等对催化剂活性的影响 .XRD结果表明 ,反应前观察不到银的晶相峰 ,反应后出现Ag(111) ,Ag(2 0 0 ) ,Ag(2 2 0 ) ,Ag(3 11)及Ag(2 2 2 )的特征银晶相峰 ,SEM结果与XRD吻合得很好 .该种特异结构的催化剂具有对甲醇直接脱氢制甲醛的优异性能 ,其甲醇转化率达到 95 .0 % ,甲醛得率也高达 81.2 % 。

The sol gel method was applied to prepare a novel Ag SiO 2 Al 2O 3 catalyst which showed high activity in the reaction of direct dehydrogenation of methanol to formaldehyde. The influence of silver loading, calcination temperature and reaction temperature on the catalytic activity was investigated, respectively. XRD patterns show that there are no sharp diffraction peaks before reaction, but after reaction, a set of sharp peaks corresponding to Ag(111) , Ag(200), Ag(220), Ag(311) and Ag(222) are observed. SEM results accord well with those from XRD. The special structure of the novel Ag SiO 2 Al 2O 3 catalyst may lead to its excellent catalytic performance (95.0% of conversion of methanol and 81.2% of HCHO yield), which is the best of all the previous results.