纳米薄片PtSnNa/MFI催化剂的制备及其丙烷脱氢性能研究

采用水热合成法和浸渍法制备了不同硅铝比的纳米薄片负载型PtSnNa/MFI系列分子筛催化剂,并考察了纳米薄片催化剂的丙烷脱氢性能。采用XRD、SEM、TEM、²⁷Al MAS NMR、N_2吸附-脱附、FTIR等方法对催化剂的形貌、孔结构及物性参数等进行了表征。表征结果显示,催化剂具有纳米薄片交叉构成的球形形貌和介孔结构,纳米薄片的厚度为20～40nm,催化剂中的Pt分散于纳米薄片分子筛表面。实验结果表明,硅铝比为100和500的MFI分子筛制备的PtSnNa/MFI-100和PtSnNa/MFI-500催化剂在丙烷脱氢反应中都表现出较好的催化性能,在反应温度为600℃、丙烷的重时空速为3 h^-1、常压的条件下反应40 h时,丙烷转化率约为40%,丙烯选择性约为94%。

Preparation of nanosheet supported PtSnNa/MFI catalyst and its catalytic performance on propane dehydrogenation

MFI zeolite nanosheets with different silica-alumina ratios were synthesized via hydrothermal method,and further used as supports to prepare PtSnNa/MFI catalysts. The catalytic performance of nanosheets catalysts for propane dehydrogenation was studied. The morphology,pore structure and physical property parameter of the catalysts were characterized by XRD,SEM,TEM, 27Al MAS NMR,N2 adsorption-desorption and FTIR techniques. The results show that the catalysts have ball-like morphologies formed by cross-stacking of nanosheets with 20-40 nm in thickness,and mesoporous structures,and the Pt particles are well dispersed on the surface of nanosheets zeolite. The results indicate that both PtSnNa/MFI-100 and PtSnNa/MFI-500 catalysts exhibit excellent catalytic performance. After reacting for 40 h under the reaction temperature of 600 ℃,WHSV of propane of 3 h-1,and atmospheric pressure,the propane conversion and propylene selectivity still remain around 40% and 94% respectively.