Selective Hydrogenation of CO<sub>2</sub> to Aromatics over Composite Catalyst Comprising NaZnFe and Polyethylene Glycol-Modified HZSM-5 with Intra- and Intercrystalline Mesoporous Structure
Qisheng Jiang, Guiyao Song, Yangzhou Zhai, Chonghao Chen, Zihao Wang, Huimin Yuan, Zhixiang Zhang, Dianhua Liu
Abstract
CO 2 hydrogenation to aromatics can significantly reduce emissions of the CO 2 and provide a complementary route for the production of aromatics. Herein, we report a composite catalyst comprising Na- and Zn-promoted Fe catalyst (NaZnFe) and highly stable hierarchical nanocrystalline HZSM-5 modified by PEG for CO 2 hydrogenation to aromatics. The subtle synergy between Na and Zn in NaZnFe promoted the formation and exposure of active iron species and the conversion of CO 2 and intermediates. In addition, the PEG modification of HZSM-5 cannot only fabricate intracrystalline mesopores to improve mesoporosity but also provide appropriate acidity, endowing high aromatic selectivity and catalytic stability. Significantly, the high-efficiency diffusion on hierarchical HZSM-5 intensifies the synergistic effect in the catalytic system. The composite catalyst could suppress the total selectivity of CO and CH 4 to less than 15% with an aromatic selectivity of up to 63.68% among all hydrocarbons and BTX selectivity in aromatics of up to 56.35% at a CO 2 conversion of 42.08%.