High surface area Ce_(0.9)Cu_(0.1)O_(2-δ)and Ce_(0.9)Mn_(0.1)O_(2-δ) solid solutions for CO and HCHO oxidation

摘要

Ce_(0.9)Cu_(0.1)O_(2-δ) and Ce_(0.9)Mn_(0.1)O_(2-δ) solid solutions with high surface area (> 100 m~2 g~(-1)) have been prepared by a modified citrate sol-gel method. XRD results confirm the formation of Ce_(0.9)X_(0.1)O_(2-δ) (where X = Cu or Mn) solid solution. Raman results indicate that a higher concentration of oxygen vacancies is obtained on the Ce_(0.9)Cu_(0.1)O_(2-δ) catalyst compared to that of Ce_(0.9)Mn_(0.1)O_(2-δ). In situ DRIFTS results show the chemisorption of CO on the Ce_(0.9)Cu_(0.1)O_(2-δ) catalyst, but there is no chemisorption of CO on the Ce_(0.9)Mn_(0.1)O_(2-δ) catalyst. For CO oxidation, Ce_(0.9)Cu_(0.1)O_(2-δ) shows higher activity than Ce_(0.9)Mn_(0.1)O_(2-δ), due to the higher concentration of oxygen vacancies and the strong chemisorption of CO on the catalyst. For HCHO oxidation, Ce_(0.9)Mn_(0.1)O_(2-δ) shows slightly higher activity than Ce_(0.9)Cu_(0.1)O_(2-δ), due to the fact that the lattice oxygen is more easily reducible in Ce_(0.9)Mn_(0.1)O_(2-δ) than in Ce_(0.9)Cu_(0.1)O_(2-δ).