ABSTRACT This study introduces a gold nanoparticles catalyst (AuNPs) supported on ceria‐zirconia oxide, prepared by deposition‐precipitation (Au/CZ‐dep) and chemical reduction (Au/CZ‐red). The as‐prepared catalysts were tested in CO oxidation by O 2 and soot oxidation under different oxidizing atmospheres (O 2 , NO 2 +NO+O 2 ). The characterization results confirm the formation of AuNPs. The XPS results indicate the formation of Au 0 and Au 3+ species on the surface of Au/CZ‐dep, while the surface of Au/CZ‐red contained only metallic Au 0 species. The latter exhibited higher homogeneity, smaller particle size, and better dispersion on the CeZrO 2 surface., compared to Au/CZ‐dep. CO oxidation is easier in the presence of gold and is better oxidized on the Au/CZ‐dep catalyst. However, the Au/CZ‐red catalyst has better reaction stability, making it more attractive. Structural and reactive characterizations show that higher dispersion of Au 0 particles on the support and smaller particle sizes lead to better catalytic performance. In terms of soot oxidation, good results are obtained. The Au/CZ‐dep catalyst improves the performance of CeZrO 2 support not only in terms of activity but also in terms of CO 2 selectivity, which is an important parameter in the oxidation of exhaust gases. In this reaction, the presence of both Au 0 and Au 3+ seems to enhance the performance.
Akef et al. (Thu,) studied this question.