Surface and catalytic properties of Cu–Ce–O composite oxides prepared by combustion method

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Vol. 220; no. 1; pp. 261 - 269
• Main Authors: Rao, G.Ranga, Sahu, H.Ranjan, Mishra, Braja Gopal
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.06.2003
• Subjects: Combustion synthesis; CuO clusters and dimers on CeO 2; Cu–Ce–O composite catalyst; Electron paramagnetic resonance (EPR); H 2O 2 decomposition; Temperature programmed reduction (TPR); Combustion synthesis; Cu–Ce–O composite catalyst; H 2O 2 decomposition; Electron paramagnetic resonance (EPR); CuO clusters and dimers on CeO 2; Temperature programmed reduction (TPR)
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/S0927-7757(03)00080-3

Surface and catalytic properties of Cu–Ce–O composite materials prepared by solution combustion method have been investigated. The materials are characterized by X-ray diffraction (XRD), temperature programmed reduction (TPR) and electron paramagnetic resonance spectroscopy (EPR). The results of EPR and TPR show finely dispersed Cu 2+ species on ceria matrix with low copper content. The Cu 2+ species exists in the form of dimers and clusters which are not evident in XRD. In addition CuO is also present as small clusters which grow to larger size at higher Cu content. There is no evidence of CuO forming a solid solution with fluorite CeO 2 in combustion method. The Cu 2+ species mostly appear on surface rather than in the bulk. Hydrogen peroxide decomposition kinetics has been carried out on Cu–Ce–O composite materials to investigate the effect of crystalline and well-dispersed copper oxide phases on CeO 2. From kinetic results, the catalyst materials can be grouped into highly dispersed as well as crystalline CuO phases present on CeO 2 matrix. Two parallel compensating lines for dispersed and crystalline CuO phases on CeO 2 are observed in ln A versus E a plot indicating the compensation effect in H 2O 2 decomposition. This observation is consistent with XRD and EPR results.