Chem. J. Chinese Universities ›› 2025, Vol. 46 ›› Issue (2): 20240455.doi: 10.7503/cjcu20240455

• Physical Chemistry • Previous Articles     Next Articles

Preparation of MO δ /3DOM ZSM-5 Catalysts and Their Catalytic Performance for the Simultaneous Removal of Soot and NOx

WANG Lanyi1, WANG Shiwei1, CHEN Xinyu1, YU Di2, ZHANG Chunlei2, FAN Xiaoqiang1, YU Xuehua1(), ZHAO Zhen1,2()   

  1. 1.Institute of Catalysis for Energy and Environment,College of Chemistry and Chemical Engineering,Shenyang Normal University,Shenyang 110034,China
    2.State Key Laboratory of Heavy Oil Processing,China University of Petroleum,Beijing 102249,China
  • Received:2024-10-08 Online:2025-02-10 Published:2024-12-07
  • Contact: YU Xuehua, ZHAO Zhen E-mail:yuxuehua1986@163.com;zhenzhao@cup.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(22402129);the National Key R&D Program of China(2022YFB3506200);the Fundamental Research Funds for the Liaoning Universities, China(LJ202410166024);the Postgraduate Education Reform Project of Liaoning Province, China(LNYJG2023280);the Excellent Youth Science Foundation of Liaoning Province, China(2022-YQ-20);the Liaoning Xingliao Talented Youth Top Talent Program, China(XLYC2203007);the Doctoral Initiation Fund of Shenyang Normal University, China(BS202416)

Abstract:

Soot particles and NOx, as the main pollutants in diesel engine exhaust, have caused a serious threat to people's health and the surrounding environment. Therefore, the catalytic purification of soot and NOx is of wide concern. In this work, the three-dimensionally ordered macroporous(3DOM) ZSM-5 zeolite catalyst with unique pore structures was prepared and taken as a carrier. The 3DOM ZSM-5 supported MOδ(M=Mn, Fe, Co, Ce, Pr, W) catalysts were also prepared. The prepared catalysts have a unique hierarchical pore structure, which is conducive to the capture and mass transfer of soot and small molecules such as NOx, thereby enhancing the catalytic performance of the catalysts. Among the prepared catalysts, MnOδ/3DOM ZSM-5 catalyst exhibits the best catalytic performance for the simultaneous removal of soot and NOx, and its peak temperature for soot combustion is the lowest(453 ℃), the initial temperature for NO conversion above 80% is the lowest(184 ℃) and the temperature window(184—362 ℃) over 80% NO conversion is wider. The excellent catalytic performance of MnOδ/3DOM ZSM-5 is related to the good redox ability, abundant acid sites, sufficient reactive oxygen species, and rich hierarchical pore structures. Meanwhile, MnOδ/3DOM ZSM-5 catalyst also has the highest intrinsic activity according to the kinetic test results. In addition, based on the results of the activity test and in situ diffuse reflectance infrared spectroscopy(in situ DRIFTS), the reaction mechanisms of the catalyst at different temperatures were proposed. At low temperatures (<300 ℃), the reaction mainly belongs to denitrification, following the Eley-Rideal(E-R) mechanism. Soot combustion mainly occurs at high temperatures(>300 ℃), including activated oxygen mechanism and NO2 assisted mechanism.

Key words: MOδ/3DOM ZSM-5 catalyst, Soot combustion, NOx removal, Reaction mechanism

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