Copper-ceria catalysis

Pale yellow cerium dioxide (ceria, ceric oxide) has the fluorite structure and is used in catalysis" ", solid oxide fuel cells (SOFC)", thin film optical waveguides" , reversible oxygen storage materials for automobile catalysts" and for doping copper oxide superconductors". The diverse cerium enolate precursors and deposition methods used in the formation of cerium oxide thin films are summarized in Table 6, whereby the most common precursor for ceria is Ce(thd)4. 

Figures 3 and 4 summarise the catalysis experiments results for the mixed copper-cerium oxide and pristine ceria samples for the NO denox reaction. It can be seen from Figure 3 that the selectivity towards N2 was very high, and for one of the samples higher than for pristine ceria. However, as it can be seen fi om Figure 4 the...

The nature of the outer-layer of the Cu-Zn based catalysts and the role of the different active sites are still a topic of investigation. Metallic copper is implicated as being the dominant oxidation state of the metal during the reaction. However, the presence of Cu+ is also important as a small amount of oxygen increases the reaction rate.51,66 Shen et al.67 found on ceria supported copper catalyst that in spite of the reductive reaction atmosphere, metallic copper particles on cerium oxide were oxidised during reaction and the catalyst was activated. The formation of the copper oxide species was considered indispensable for the onset of high catalytic activity. Synergy between Cu and ZnO in the catalysis of methanol synthesis... 

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