Acta Chimica Sinica ›› 2023, Vol. 81 ›› Issue (8): 874-883.DOI: 10.6023/A23040174 Previous Articles     Next Articles

Article

团簇Au/CeO2的制备及其催化CO氧化反应构效关系的研究

付信朴a, 王秀玲a, 王伟伟a, 司锐b, 贾春江a,*()   

  1. a 山东大学化学与化工学院 胶体与界面化学重点实验室 特种聚合材料重点实验室 济南 250100
    b 中山大学材料学院 广东深圳 518107
  • 投稿日期:2023-04-28 发布日期:2023-09-14
  • 作者简介:
    庆祝《化学学报》创刊90周年.
  • 基金资助:
    项目受国家重点研发项目(2021YFA1501103); 国家杰出青年基金项目(22225110); 国家自然科学基金(22075166); 国家自然科学基金(22271177); 山东大学未来学者项目资助

Fabrication and Mechanism Study of Clustered Au/CeO2 Catalyst for the CO Oxidation Reaction

Xinpu Fua, Xiuling Wanga, Weiwei Wanga, Rui Sib, Chunjiang Jiaa()   

  1. a Key Laboratory of Special Aggregated Materials, Key Laboratory for Colloid and Interface Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100
    b School of Materials, Sun Yat-Sen University, Shenzhen, Guangdong 518107
  • Received:2023-04-28 Published:2023-09-14
  • Contact: *E-mail: jiacj@sdu.edu.cn
  • About author:
    Dedicated to the 90th anniversary of Acta Chimica Sinica.
  • Supported by:
    National Key Research and Development Program of China(2021YFA1501103); National Science Fund for Distinguished Young Scholars of China(22225110); National Natural Science Foundation of China(22075166); National Natural Science Foundation of China(22271177); Young Scholars Program of Shandong University

Supported Au-based catalysts have been attracting continuous attention owing to their outstanding performance in various catalytic applications. However, the complicated environment on the catalyst surface severely hampered the unambiguous illustration of the structural-function relationship for Au-based catalysts. In this work, we developed a facile strategy to fabricate various Au species [Aun (n>1), Auδ (0<n<1) and Au0] onto the CeO2 support, which the Au/CeO2 interaction was distinctively modulated by the CeO2-x with different calcination temperatures. As-prepared Au/CeO2-x were valued as catalysts for CO oxidation reaction, which is important for both environmental application and model catalysis. The as-formed clustered Au with δ+ oxidation state on CeO2-400 demonstrates the best catalytic performance at 50 ℃, while the Au nanoparticles with dominant Au0 atoms are superior for catalyzing CO oxidation at room temperature. However, the monodispersed Aun single-sites with the highest dispersion are almost inactive for CO oxidation below 50 ℃. On the basis of structural characterizations and in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) results, we reasonably speculated that the electronic state of Au species plays a predominant role at room temperature for catalytic performance owing to the differentiated CO adsorption ability. This speculation is well in line with our former research finding that the Aun sites are weak in capturing CO molecules and Au0 is favorable for CO adsorption. The surficial O atoms, especially the lattice O atoms, play a minor role in catalyzing CO oxidation for the Au particles within Au/CeO2-700, implying that the reactant molecules might prefer a L-H pathway at room temperature. In contrast, the clustered Auδ with moderate CO adsorption ability and abundant interfacial site was apt to participate in the surface reaction with a MvK pathway, in which the reaction between surficial lattice O atoms and adsorbed CO molecules significantly contribute to the catalytic activity. Therefore, the Au/CeO2-400 catalyst coupling with moderate CO adsorption ability and abundant active O atoms displayed the best catalytic efficiency at elevated temperatures. These findings in this work provided a facile route for the fabrication efficient Au/CeO2 catalyst, and shed light on the molecular understanding of the reaction path over various Au sites.

Key words: supported gold catalyst, ceria-based material, CO oxidation, in-situ characterizations, reaction mechanism