Thermal activation of Pd/CeO2-SnO2 catalysts for low-temperature CO oxidation

• Published in: Applied catalysis. B, Environmental Vol. 277; p. 119275
• Main Authors: Slavinskaya, E.M., Zadesenets, A.V., Stonkus, O.A., Stadnichenko, A.I., Shchukarev, A.V., Shubin, Yu.V., Korenev, S.V., Boronin, A.I.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.11.2020; Elsevier BV
• Subjects: Activation; Carbon monoxide; Catalysts; Catalytic activity; CeO2-SnO2 composite; Ceria; Cerium oxides; CO oxidation; Fluorite; Low temperature; Nanoparticles; Oxidation; Roasting; Solid solutions; Thermal stability; Tin dioxide; Water resistance; Pd; CO oxidation; Thermal stability; Ceria; CeO2-SnO2 composite
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2020.119275

[Display omitted] •The counter precipitation method was used to synthesise composite catalysts Pd/CeO2-SnO2•The calcination at 800−1000 °C results in strong enhancement of low-temperature CO oxidation•Pd/CeO2-SnO2 catalysts are thermally stable up 1100 °C due to formation of nanoheterogeneous structure•SnO2 nanoparticles serve as stabilisers of PdxCe1-xO2-δ nanoparticles•Pd/CeO2-SnO2 catalysts are characterized by high water resistance in CO oxidation In this work, the counter precipitation method was used to synthesise Pd/CeO2-SnO2 catalysts, which possess excellent low-temperature activity and high thermal stability. It was revealed that calcination of Pd/CeO2-SnO2 catalysts at 800−1000 °C induces significant growth of catalytic activity in CO oxidation at T<150 °C. This effect of thermal activation for Pd/CeO2-SnO2 catalysts was enhanced when water was admitted to the reaction mixture. In the presence of water the T50 value for the Pd/CeO2-SnO2 catalyst calcined at 900 °C becomes 45 °C lower than for the Pd/CeO2 catalyst. It was found that calcination of the catalysts at T<600 °C leads to the formation of solid solutions based on the fluorite and rutile structures. As the calcination temperature is raised above 600 °C, the solid solutions decompose with formation of catalytically active PdxCe1-xO2-δdispersed phase on the surface of SnO2 nanoparticles. The formed nanoheterogeneous structure provides both high thermal stability and high water resistance of Pd/CeO2-SnO2 catalysts.