Luo Wenbo, Liu Haoyu, Yuan Hong, Liu Hao
School of Chemistry and Chemical Engineering, North Minzu University, Yinchuan 750021, China.
State Key Laboratory of National Ethnic Affairs Commission Chemical Technology, North Minzu University, Yinchuan 750021, China.
ACS Omega. 2024 Apr 2;9(15):17054-17065. doi: 10.1021/acsomega.3c08748. eCollection 2024 Apr 16.
Hierarchical zeolites can provide multidimensional spatial networks and, therefore, have significant potential as catalysts for the cracking of biomass to generate light olefins. The present work synthesized the diquaternary ammonium-type surfactant [CH-N(CH)-(CH)-N(CH)-CH]Br, incorporating hydrophobic 18-carbon alkyl groups for usage as a structure-directing agent. This compound was subsequently used to prepare nanosheets of a hierarchical ZSM-5 two-dimensional zeolite (HNZSM-5) through a one-pot hydrothermal method. The crystal phase, morphology, and hierarchical structure of the HNZSM-5 were analyzed using various techniques, including X-ray diffraction, electron microscopy, and N adsorption/desorption. When applied to the catalytic cracking of a waste cooking oil model compound, the HNZSM-5 exhibited superior activity and stability compared with a conventional ZSM-5. This performance was attributed to the more accessible acid sites and unique lamellar structure of the former material. The HNZSM-5 also outlasted the conventional zeolite, showing deactivation after 45 h of reaction compared with 20 h, indicating exceptional stability and excellent resistance to coking.
分级沸石可以提供多维空间网络，因此作为生物质催化裂解制备轻质烯烃的催化剂具有巨大潜力。本工作合成了含有疏水18碳烷基的双季铵型表面活性剂[CH-N(CH)-(CH)-N(CH)-CH]Br，用作结构导向剂。随后通过一锅水热法用该化合物制备了分级ZSM-5二维沸石（HNZSM-5）的纳米片。使用包括X射线衍射、电子显微镜和N吸附/脱附在内的各种技术对HNZSM-5的晶相、形貌和分级结构进行了分析。当应用于废食用油模型化合物的催化裂解时，与传统ZSM-5相比，HNZSM-5表现出优异的活性和稳定性。这种性能归因于前者材料中更容易接近的酸性位点和独特的层状结构。HNZSM-5的使用寿命也比传统沸石更长，传统沸石在反应20小时后失活，而HNZSM-5在反应45小时后才失活，表明其具有出色的稳定性和优异的抗结焦性能。
