焙烧温度对Pt/Al_2O_3催化剂催化纤维素转化性能的影响

Effect of calcination temperature on catalytic conversion of cellulose over Pt/Al_2O_3 catalyst

以溶剂挥发诱导自组装方法合成的有序介孔氧化铝(MA)为载体负载铂,制备了Pt/MA催化剂。考察了载体和催化剂焙烧温度对Pt/MA催化剂催化纤维素转化性能的影响。采用X射线衍射、N2物理吸附、透射电镜和NH3程序升温脱附等手段对载体和催化剂进行了表征,随着载体焙烧温度的升高,氧化铝的有序度、晶相、比表面积、酸量、铂粒径大小均有明显变化。催化结果表明,载体焙烧温度和催化剂焙烧温度对催化剂的催化性能有显著影响。以800℃焙烧的氧化铝为载体负载铂,再经400℃焙烧制得的催化剂活性最高,六元醇的选择性达到了78.5%。

Mesoporous Pt/MA catalysts were prepared using the ordered mesoporousγ-Al2 O3 （MA）obtained via one-pot evaporation-induced self-assembly method as a carrier-supported platinum.The effects of calcination temperature of the supports and the catalysts on the catalytic performance for conversion of cellulose were investigated.The properties of the supports and the cata-lysts were characterized by the means of X-ray diffraction （XRD）,N2 physisorption （BET）,transmission electron microscopy （TEM）and temperature-programmed desorption of NH3 （NH3-TPD）.As the calcination temperature increases,the crystal structure,the specific surface area,the size of platinum particles and the amount of the acid sites change obviously.The catalytic reaction results reveal that the catalytic properties are affected significantly by the calcination temperature of support and catalyst. The Pt/γ-Al2 O3 catalyst calcinated at the temperature of 400 ℃ with theγ-Al2 O3 support calcinated at 800 ℃ shows the best catalytic activity,which makes the selectivity of hexitol up to 78.5%.