Synthesis of silica supported AuCu nanoparticle catalysts and the effects of pretreatment conditions for the CO oxidation reaction

Journal Article · Sat Jan 01 04:00:00 EST 2011 · Physical Chemistry Chemical Physics. PCCP (Print)

DOI:https://doi.org/10.1039/c0cp01859g· OSTI ID:1060263

Bauer, J. Chris; Mullins, David; Li, Meijun; Wu, Zili; Payzant, E. Andrew; Overbury, Steven H.; Dai, Sheng

Supported gold nanoparticles have generated an immense interest in the field of catalysis due to their extremely high reactivity and selectivity. Recently, alloy nanoparticles of gold have received a lot of attention due to their enhanced catalytic properties. Here we report the synthesis of silica supported AuCu nanoparticles through the conversion of supported Au nanoparticles in a solution of Cu(C₂H₃O₂)₂ at 300 °C. The AuCu alloy structure was confirmed through powder XRD (which indicated a weakly ordered alloy phase), XANES, and EXAFS. It was also shown that heating the AuCu/SiO₂ in an O₂ atmosphere segregated the catalyst into a Au–CuO_x heterostructure between 150 °C to 240 °C. Heating the catalyst in H₂ at 300 °C reduced the CuO_x back to Cu0 to reform the AuCu alloy phase. It was found that the AuCu/SiO₂ catalysts were inactive for CO oxidation. However, various pretreatment conditions were required to form a highly active and stable Au–CuO_x/SiO₂ catalyst to achieve 100% CO conversion below room-temperature. This is explained by the in situFTIR result, which shows that CO molecules can be chemisorbed and activated only on the Au–CuO_x/SiO₂ catalyst but not on the AuCu/SiO₂ catalyst.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1060263
• Journal Information: Physical Chemistry Chemical Physics. PCCP (Print), Journal Name: Physical Chemistry Chemical Physics. PCCP (Print) Journal Issue: 7 Vol. 13; ISSN PPCPFQ; ISSN 1463-9076
• Publisher: Royal Society of Chemistry
• Country of Publication: United States
• Language: English

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36 MATERIALS SCIENCE