t-ZrO2/SAPO-34质量比对t-ZrO2/SAPO-34复合催化剂物化性质及其甲醇制烯烃催化性能的影响

采用介孔t-ZrO2对微孔SAPO-34分子筛进行复合改性，利用水热包覆技术制备了t-ZrO2/SAPO-34复合催化剂，研究了t-ZrO2与SAPO-34质量比对复合催化剂物化性质和MTO催化性能的影响。采用XRD、FT-IR、SEM、NH3-TPD和BET等手段对不同复合催化剂的晶相组成、骨架结构、微观形貌、表面酸性及孔结构进行分析表征。结果表明，质量比对t-ZrO2/SAPO-34复合催化剂的物化性质和催化性能影响较大。过高或过低t-ZrO2:SAPO-34质量比制得复合催化剂中SAPO-34分子筛结晶度和骨架结构特征均有所减弱，分别呈现以介孔为主和以微孔为主的孔结构特征；当质量比为1:1时，制得复合催化剂形成了包覆相结构和微-介孔层级结构（微孔比表面积112.91 m2·g-1，介孔比表面积176.02 m2·g-1，总比表面积为288.93 m2·g-1，总孔容0.19 cm3·g-1），总酸量较大（0.344 mmol/g）；在常压、反应温度380 ℃、N2流速20 mL·min-1、进料空速2 h-1MTO反应条件下，复合催化剂表现出优越催化性能、稳定性及反应寿命，甲醇转化率和低碳烯烃选择性分别达100%和90.54%，催化寿命达1130 min，与单一SAPO-34分子筛相比，催化寿命延长了768 min。

Effects oft-ZrO2/SAPO-34 Mass Ratio on the Physicochemical Properties and Catalytic Performance oft-ZrO2/SAPO-34 Composite Materials in Methanol-to-Olefin Reaction

The microporous SAPO-34 molecular sieve was promoted by using mesoporous t-ZrO2 to prepare t-ZrO2/SAPO-34 composite catalyst, hydrothermal coating method and effect of mass ratio for t-ZrO2:SAPO-34 on the physicochemical properties and MTO catalytic performance of the composite catalyst fabricated via hydrothermal coating route was investigated in this paper. These obtained composite catalysts were extensively characterized by XRD, FT-IR, SEM, NH3-TPD and BET techniques to investigate their crystalline phase, skeletal structure, morphology, surface acidity and pore structure. The results indicated that various mass ratios for t-ZrO2:SAPO-34 posed significant impact on the physicochemical properties and MTO catalytic performance of t-ZrO2/SAPO-34 composite catalyst. The crystallinity and skeleton characteristics of SAPO-34 molecular sieve in composite catalyst were significantly weakened with higher or lower t-ZrO2:SAPO-34 mass ratio, and the pore structure of these obtained composite catalysts were dominated with almost mesopore and practically microporous system respectively. As the mass ratio of 1:1, the homogeneous continuous coating phase and hierarchical structure (microporous specific surface area of 112.91 m2·g-1, mesoporous specific surface area of 176.02 m2·g-1, total specific surface area of 288.93 m2·g-1, the total pore volume of 0.19 cm3·g-1) with total amount of acid of 0.344 mmol/g were successfully obtained in the composite catalyst, and the composite catalyst exhibited excellent catalytic performances, stability and reaction life with methanol conversion of 100%, light olefins selectivity of 90.54%, and catalytic lifetime of 1130 min under the conditions of atmospheric pressure, reaction temperature of 380 ℃, nitrogen flow rate of 20 mL·min-1 and feed speed of 2 h-1. Compared with the single SAPO-34 molecular sieve, the catalytic lifetime of the t-ZrO2/SAPO-34 composite catalyst was extended by 768 min.