SIZE AND SHAPE EFFECTS IN NANOSTRUCTURED CATALYSTS BASED ON COMBINATIONS OF COPPER AND CERIUM OXIDES FOR PREFERENTIAL OXIDATION OF CO IN H2-RICH STREAMS

摘要

Catalysts based on combinations between copper and ceriumrnoxides are an interesting alternative to noble metal ones for processesrninvolved in production/purification of hydrogen produced fromrnhydrocarbons or biomass like the water-gas shift or preferentialrnoxidation of CO reactions. Active sites for such processes have beenrnproposed to correspond to reduced species formed at the interfacernbetween both oxides. The morphological characteristics of suchrninterfaces appear therefore most interesting in order to determinernredox and catalytic properties of this type of systems for suchrnprocesses. In principle, the combination of the two oxides can berndone in direct (ceria as support of copper oxide) or inverse (copperrnoxide as support of ceria) configurations. Every one of these twornconfigurations displays specific redox/catalytic properties. Thernpresentation will discuss structure/activity relationships for this typernof catalyst/process with the use of a multitechnique characterizationrnapproach including in situ-XAFS –XPS and –DRIFTS as well asrnconventional structural characterization, DFT+U calculations andrnactivity tests.