Noble Metal-Perovskite Hybrid Materials

As already mentioned, one of the principal aims of using perovskite-type oxides as oxidation catalysts is to avoid the use of expensive and low thermally stable noble-metal-supported catalysts (e.g., Pt/Al203). Thus, by modifying the perovskite composition using alkaline earth metal or metal transition cations (A- and/ or B-substituted materials) and by improving their textural and defective properties during the synthesis process, it is possible to obtain perovskite-based catalysts as active as noble-metal-supported ones for the low-temperature CO oxidation reaction. Nevertheless, some authors have recently claimed the 

Therefore, the presence of gold in a relatively high loading (3-8 wt%) strongly boosted the efficiency of the catalysts, even at the subambient temperature range 

For all the catalysts studied by these authors, it was concluded that the high catalytic performance might be associated with the relatively high surface area, an improved Oads concentration (measured by XPS analysis Table 20.1), their 

Catalyst r o%(°c) Oads/Oiatt molar ratio Reference 

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