Elucidation of Ce/Zr ratio effects on the physical properties and catalytic performance of CuO/CeZrO catalysts

• Published in: Catalysis science & technology 2024-12, Vol.14 (24), p.717-7123
• Main Authors: Sifat, Mohammed, Luchowski, Michal, Pophali, Amol, Jiang, Wenhui, Lu, Yunfan, Kim, Byeongseok, Kwon, Gihan, Yoon, Kwangsuk, Kim, Jihun, An, Kwangjin, Shim, Sang Eun, Song, Hocheol, Kim, Taejin
• Format: Article
• ISSN: 2044-4753; 2044-4761
• DOI: 10.1039/d4cy01012d

Although cerium oxide (CeO 2 ) is widely used as a catalyst support, its limited defect sites and surface oxygen vacancy/mobility should be improved. The incorporation of zirconium (Zr) in the cerium (Ce) lattice is shown to increase the number of oxygen vacancies and improve catalytic activity. Using a fixed surface density (SD) of copper (∼2.3 Cu atoms per nm 2 ) as a surface species, the role of the support (Ce y Zr 1− y O 2 ( y = 1.0, 0.9, 0.6, 0.5, and 0.0)) and defect site effects in the CO oxidation reaction was investigated. Spectroscopic ( e.g. , Raman, XRD, XPS) and microscopic ( e.g. , SEM-EDX, HR-TEM) characterization techniques were applied to evaluate the defect sites, crystallite size, lattice parameters, chemical composition, oxidation states of elements and microstructure of the catalysts. The CO oxidation reaction with varied CO : O 2 ratios (1 : 5, 1 : 1, and 1 : 0.5 (stoichiometric)) was used as a model reaction to describe the relationship between the structure and the catalytic performance of each catalyst. Based on the characterization results of Ce y Zr 1− y O 2 materials, the addition of Zr causes physical and chemical changes to the overall material. The inclusion of Zr into the structure of CeO 2 decreased the overall lattice parameter of the catalyst and increased the number of defect sites. The prepared catalysts were able to reach complete CO conversion (∼100%) at low temperature conditions (