文献类型：期刊文献

英文题名：Catalytic conversion of polyethylene into aromatics with Pt/ZSM-5: insights into reaction pathways and rate-controlling step regulation

作者：Wang, Wenjie[1];Yao, Chang[1];Ge, Xiaohu[1];Pu, Xin[1];Yuan, Jiangchun[1];Sun, Weixiao[1];Chen, Wenyao[1];Feng, Xiang[2];Qian, Gang[1];Duan, Xuezhi[1];Cao, Yueqiang[1];Yang, Zhirong[3];Zhou, Xinggui[1];Zhang, Jing[1]

机构：[1]East China Univ Sci & Technol, State Key Lab Chem Engn, 130 Meilong Rd, Shanghai 200237, Peoples R China;[2]China Univ Petr, State Key Lab Heavy Oil Proc, Qingdao 266580, Peoples R China;[3]Zhengzhou Univ, Sch Chem Engn, Zhengzhou 450001, Peoples R China

年份：2023

卷号：11

期号：27

起止页码：14933

外文期刊名：JOURNAL OF MATERIALS CHEMISTRY A

收录：;EI(收录号：20232814380399);WOS:【SCI-EXPANDED(收录号:WOS:001018099900001)】；

基金：This work was financially supported by the National Key R&D Program of China (2022YFA1503502 and 2022YFA1503503), the National Natural Science Foundation of China (22008074, 21991103, 22008067, 22008072, and 21991104), Shanghai Rising-star Program (23QA1401900) and the Natural Science Foundation of Shanghai (20ZR1415700).

语种：英文

外文关键词：Activation energy - Aromatization - Atmospheric pressure - Crystal structure - Dehydrogenation - Density functional theory - Ethylene - Platinum - Pyrolysis - Reaction intermediates

摘要：Catalytic pyrolysis of polyethylene (PE) can produce benzene, toluene, and xylene (BTX) as important building-block chemicals, and selectivity control is key to its economic and ecological efficiency. Here, we report a synergistic effect between Pt and ZSM-5 for selective production of BTX from catalytic pyrolysis of PE by providing mechanistic insights into reaction pathways of key intermediates and regulation of the rate-controlling step. A high yield (52%) of BTX was obtained at 450 degrees C under atmospheric pressure using a Pt/ZSM-5 catalyst, where Pt mainly exists in the metallic state with a cuboctahedral crystal structure. In contrast, thermal pyrolysis of PE produced linear alkenes/alkanes of wide carbon number distribution, and catalytic pyrolysis of PE over ZSM-5 led to a low BTX yield of 21% with C1-C4 alkenes/alkanes being the major products even at a higher temperature (500 degrees C). It was found that the introduction of Pt into ZSM-5 significantly decreased the aromatization onset temperature, suggesting a reduction of apparent activation energy for the aromatization of alkene intermediates during catalytic pyrolysis of PE. Density functional theory calculations reveal that the aromatization of intermediate ethylene proceeds via oligomerization, cyclization, and dehydrogenation, and the energy barrier of the rate-controlling step, i.e., dehydrogenation of C6H*(11); on Pt/ZSM-5 is much lower than that on ZSM-5. As a result, Pt enhanced the aromatization rates of light alkenes formed by PE cracking over the acid sites in ZSM-5, the synergistic effects of which contributed to the high BTX yield on Pt/ZSM-5.