Acta Chimica Sinica ›› 2023, Vol. 81 ›› Issue (7): 691-696.DOI: 10.6023/A23030074 Previous Articles     Next Articles



刘洵a,b, 江辉波a, 荆凯强a, 徐忠宁a,*(), 郭国聪a,*()   

  1. a 中国科学院福建物质结构研究所 结构化学国家重点实验室 福建福州 350002
    b 中国科学院大学 北京 100049
  • 投稿日期:2023-03-10 发布日期:2023-05-17
  • 基金资助:
    国家重点研发计划项目(2021YFB3801600); 国家重点研发计划项目(2017YFA0700103); 国家重点研发计划项目(2018YFA0704500); 中国科学院战略性先导专项课题(XDA29030600); 国家自然科学基金(22172171); 福建省自然科学基金(2022H0039); 中科院洁净能源创新研究院-榆林学院联合基金(2022010)

Introduction of Zn2+ Promotes the Catalytic Performance of Pd-based Catalyst for CO Esterification Reaction via Electron Transfer

Xun Liua,b, Hui-Bo Jianga, Kai-Qiang Jinga, Zhong-Ning Xua(), Guo-Cong Guoa()   

  1. a State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002
    b University of Chinese Academy of Sciences, Beijing 100049
  • Received:2023-03-10 Published:2023-05-17
  • Contact: *E-mail:;
  • Supported by:
    National Key Research and Development Program of China(2021YFB3801600); National Key Research and Development Program of China(2017YFA0700103); National Key Research and Development Program of China(2018YFA0704500); Strategic Priority Research Program of the Chinese Academy of Sciences(XDA29030600); National Natural Science Foundation of China(22172171); Natural Science Foundation of Fujian Province(2022H0039); Grant YLU-DNL Fund(2022010)

Coal to ethylene glycol is a crucial route in modern coal chemical industry, and the CO esterification reaction, which synthesizes dimethyl oxalate (DMO), is a key step in this process. While supported Pd-based catalysts are effective for this reaction, research on support effect is limited. In this study, we employed a two-dimensional material CoAl-LDH (layered double hydroxides) as a catalytic support to investigate the support effect for the CO esterification reaction. We prepared various LDH supports with different Co/Al molar ratios and loaded Pd metal using the ALD (atomic layer deposition) method. The successful preparation of LDH carriers was confirmed by TEM (transmission electron microscopy), XRD (X-ray diffraction), and Fourier infrared spectroscopy characterizations. The catalysts were evaluated for their catalytic performance in the CO esterification to DMO reaction. Based on the results, the support with a Co/Al molar ratio of 1∶1 was chosen for further study, as it exhibited the highest Lewis basicity in CO2-TPD (temperature programmed desorption) tests. We then prepared the Pd/ZnCoAl-LDH catalyst by doping Zn2+ into the selected CoAl-LDH support. Compared to the Pd/CoAl-LDH catalyst, the Pd/ZnCoAl-LDH catalyst exhibited better catalytic activity for the CO esterification to DMO reaction, with the conversion of CO increasing from 51.5% to 61.8%. XPS (X-ray photoelectron spectroscopy) characterization results indicated that the introduction of Zn2+ promoted electron transfer between the Pd active species and ZnCoAl-LDH, which is responsible for the higher activity of the Pd/ZnCoAl-LDH catalyst. In situ DRIRS (diffuse reflectance infrared spectroscopy) experiments demonstrated a red-shift in the adsorption peak of CO, which further confirmed the increase in electron density around the Pd active species. In addition, the 100 h stability test results showed that the introduction of Zn2+ can also enhance the stability of the catalyst. After 100 h of evaluation, the catalytic activity of Pd/CoAl-LDH catalyst decreased significantly, while the activity of Pd/ZnCoAl-LDH remained basically unchanged. This study focused on the structural design for promoting catalytic activity through enhanced Lewis-basicity, providing a reference for improving the performance of Pd-based heterogeneous catalysts.

Key words: ZnCoAl-LDH, Lewis base site, dimethyl oxalate, electron transfer