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<p>As a crucial raw material in the polyester industry, coal-based ethylene glycol often fails to meet the polyester-grade standard due to the presence of trace unsaturated impurities that compromise its ultraviolet (UV) transmittance, thereby limiting its high-end applications. In this study, a series of Zn–Ni/ZSM-5 bimetallic catalysts were successfully synthesized via a two-step in-situ hydrothermal method, wherein Zn and Ni species were confined within the ZSM-5 zeolite matrix. Their catalytic performance was systematically evaluated in the&#xa0;liquid-phase hydrogenation refining of trace unsaturated impurities in industrial-grade coal-based ethylene glycol (rather than hydrogenation of the bulk ethylene glycol solvent).&#xa0;The structure and physicochemical properties of the catalysts were comprehensively characterized by XRD, SEM, XPS, H<sub>2</sub>-TPR, NH<sub>3</sub>-TPD, and HAADF-STEM. The results reveal that Zn and Ni species are uniformly dispersed within the ZSM-5 channels and exhibit a significant electronic synergy, wherein electron transfer from Zn to Ni increases the electron cloud density of Ni species, enhances their reduction stability, and promotes the homogenization of the Ni chemical environment. Under optimal reaction conditions (120&#xa0;°C, 0.8&#xa0;MPa H<sub>2</sub>, LHSV = 2.26&#xa0;h<sup>−1</sup>), the 9%Zn-3%Ni/ZSM-5 catalyst exhibited the best hydrogenation performance, achieving UV transmittances of 64, 97, and 100% at 220&#xa0;nm, 275&#xa0;nm, and 350&#xa0;nm, respectively. These values represent increases of 24, 4, and 3% compared to the monometallic Ni<sub>3</sub>/ZSM-5 catalyst, successfully meeting the polyester-grade ethylene glycol standard. The catalytic performance surpasses that of γ-Al<sub>2</sub>O<sub>3</sub>- and SBA-15-supported metal catalysts, as well as conventional distillation and resin-based purification methods. This study demonstrates that the Zn–Ni bimetallic synergistic catalytic system constructed via in-situ hydrothermal encapsulation provides a viable route for the efficient hydrogenation refining of industrial-grade coal-based ethylene glycol, offering new insights for the development of low-cost, high-performance non-noble metal hydrogenation catalysts.</p> Graphical Abstract <p></p> <p>This figure shows an intuitive process diagram (<b>a</b>) and detailed hydrogenation performance (<b>b</b>-<b>c</b>)</p>

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Construction of In-Situ Encapsulated Zn–Ni Bimetallic ZSM-5 Catalyst and Its Application in Hydrogenation Refining of Coal-Based Ethylene Glycol

  • 期刊论文

  • 发表日期：

    2026年5月30日

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  • Haoyu Jiang,
  • Yingwen Huang,
  • Wei Wei,
  • Huidan Lu,
  • Jianjian Yang,
  • Yongping Liu

摘要

As a crucial raw material in the polyester industry, coal-based ethylene glycol often fails to meet the polyester-grade standard due to the presence of trace unsaturated impurities that compromise its ultraviolet (UV) transmittance, thereby limiting its high-end applications. In this study, a series of Zn–Ni/ZSM-5 bimetallic catalysts were successfully synthesized via a two-step in-situ hydrothermal method, wherein Zn and Ni species were confined within the ZSM-5 zeolite matrix. Their catalytic performance was systematically evaluated in the liquid-phase hydrogenation refining of trace unsaturated impurities in industrial-grade coal-based ethylene glycol (rather than hydrogenation of the bulk ethylene glycol solvent). The structure and physicochemical properties of the catalysts were comprehensively characterized by XRD, SEM, XPS, H2-TPR, NH3-TPD, and HAADF-STEM. The results reveal that Zn and Ni species are uniformly dispersed within the ZSM-5 channels and exhibit a significant electronic synergy, wherein electron transfer from Zn to Ni increases the electron cloud density of Ni species, enhances their reduction stability, and promotes the homogenization of the Ni chemical environment. Under optimal reaction conditions (120 °C, 0.8 MPa H2, LHSV = 2.26 h−1), the 9%Zn-3%Ni/ZSM-5 catalyst exhibited the best hydrogenation performance, achieving UV transmittances of 64, 97, and 100% at 220 nm, 275 nm, and 350 nm, respectively. These values represent increases of 24, 4, and 3% compared to the monometallic Ni3/ZSM-5 catalyst, successfully meeting the polyester-grade ethylene glycol standard. The catalytic performance surpasses that of γ-Al2O3- and SBA-15-supported metal catalysts, as well as conventional distillation and resin-based purification methods. This study demonstrates that the Zn–Ni bimetallic synergistic catalytic system constructed via in-situ hydrothermal encapsulation provides a viable route for the efficient hydrogenation refining of industrial-grade coal-based ethylene glycol, offering new insights for the development of low-cost, high-performance non-noble metal hydrogenation catalysts.

Graphical Abstract

This figure shows an intuitive process diagram (a) and detailed hydrogenation performance (b-c)