Studies of the Catalytic Oxidation of CO Over Ag/CeO2 Catalyst

• Published in: Catalysis letters 2012-12, Vol.142 (12), p.1498-1504
• Main Authors: Kang, Yan, Sun, Min, Li, Aimin
• Format: Article
• Language: English
• Subjects: Catalysis; Catalysts; Catalytic activity; Catalytic oxidation; Cerium oxides; Chemistry; Chemistry and Materials Science; Industrial Chemistry/Chemical Engineering; Lattice vacancies; Organic chemistry; Organometallic Chemistry; Oxidation; Oxygen; Physical Chemistry; Physical properties; Raman spectroscopy; Silver; Sol-gel processes; X ray photoelectron spectroscopy
• ISSN: 1011-372X; 1572-879X
• DOI: 10.1007/s10562-012-0893-2

CO oxidation was investigated over Ag/CeO 2 and CeO 2 catalysts prepared by sol–gel method in this work. The catalytic activity of Ag/CeO 2 was higher than pure CeO 2 . The chemico-physical properties of catalysts were characterized by XRD, TEM, XPS, H 2 -TPR and Raman spectroscopy. The characterization results indicated that a part of silver was inserted into the lattice of CeO 2 and aroused the expansion of lattice. Raman studies of Ag/CeO 2 demonstrated that the concentration of oxygen vacancies greatly increased at 5 vol.% CO/N 2 atmosphere and gradually decreased at O 2 atmosphere with the rising temperature from 30 to 300 °C respectively. However, a different behavior was observed over pure CeO 2 . The obtained Raman results showed that the oxygen storage capability of Ag/CeO 2 was superior to that of CeO 2 and larger amount of lattice oxygen of the former took part in the oxidation reaction evidenced by changes of oxygen vacancy. On the basis of characterization data, it was proposed that the introduction of Ag into CeO 2 facilitated the activation of lattice oxygen and formation of oxygen vacancies. These features may be responsible for the higher catalytic activity of Ag/CeO 2 for CO oxidation. Graphical Abstract