无机材料学报2024，Vol.39Issue(8)：945-954,中插11-中插14,14.DOI:10.15541/jim20240016
晶种诱导合成ZSM-5多晶聚集体及其在甲醇制碳氢化合物中的催化性能
Polycrystalline ZSM-5 Aggregates Induced by Seed and Catalytic Performance in Methanol to Hydrocarbon
摘要
Abstract
Synthesis of ZSM-5 zeolite typically utilizes small molecule polyamines or quaternary ammonium salts as organic structure guiding agent(OSDA).By contrast,the OSDA-free hydrothermal synthesis system eliminates the use of organic templates and the subsequent calcination procedure.This not only reduces the cost of synthesis,but also prevents environmental pollution from the combustion of organic templates,representing an eco-friendly approach.Despite this,literature suggests that even so-called template-free synthesis systems often involve trace amount of organic substances like alcohol.In the present work,a calcined commercial ZSM-5 zeolite was served as seed,with sodium aluminate as aluminum source and silica sol as silicon source,ensuring an entirely template-free synthesis system.Polycrystalline ZSM-5 aggregates consisted of rod-like nanocrystals were successfully prepared in the completely OSDA-free system.Effects of the Si/Al ratio in ZSM-5 seed,dosage and crystallization conditions such as crystallization temperature and crystallization time on ZSM-5 synthesis were investigated.The results show that a highly crystallinity ZSM-5 aggregate consisting of primary nano-sized crystals less than 100 nm is produced from a gel precursor with 5.6%(in mass)seed after hydrothermal treatment for 48 h.Furthermore,the Si/Al ratio in ZSM-5 seed has little effect on the topological structure and pore structure of the synthesized samples.However,the seeds with a low Si/Al ratio facilitate faster crystallization of zeolite and enhance the acidity,especially the strong acid centers,of the catalyst.The catalytic performance of the synthesized polycrystalline ZSM-5 was evaluated during dehydration of methanol and compared with a commercial reference ZSM-5r.The results exhibit that as compared with the reference catalyst,the fabricated sample has a longer catalytic lifetime(16 h vs 8 h)attributed to its hierarchical pores derived from the loosely packed primary nanoparticles.Additionally,the prepared polycrystalline catalyst also exhibits a higher aromatics selectivity(28.1%-29.8%vs 26.5%).关键词
ZSM-5/多晶聚集体/晶种/结构导向剂Key words
ZSM-5/polycrystalline aggregate/crystal seed/structure guiding agent分类
化学化工引用本文复制引用
王旭昌,焦楚钰,季卓,焦其瑞,秦波,杜艳泽,郑家军,李瑞丰..晶种诱导合成ZSM-5多晶聚集体及其在甲醇制碳氢化合物中的催化性能[J].无机材料学报,2024,39(8):945-954,中插11-中插14,14.基金项目
National Natural Science Foundation of China(U19B2003,21706177,21975174) （U19B2003,21706177,21975174）
Foundation Supported by China Petroleum&Chemical Corporation(121014-2) （121014-2）
