In Situ Phase Separation of NiAu Alloy Nanoparticles for Preparing Highly Active Au/NiO CO Oxidation Catalysts

Journal Article · Tue Jan 01 00:00:00 EST 2008 · ChemPhysChem

DOI:https://doi.org/10.1002/cphc.200800587· OSTI ID:1059305

Zhou, Shenghu ^[1]; Yin, Hongfeng ^[1]; Schwartz, Viviane ^[1]; Wu, Zili ^[1]; Mullins, David R ^[1]; Dai, Sheng ^[1]

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1. ORNL

In this communication, we report the synthesis of NiAu alloy nanoparticles (NPs) and their use in preparing Au/NiO CO oxidation catalysts. Because of the large differences in Ni and Au reduction potentials and the immiscibility of the two metals at low temperatures,1, 2 NiAu alloy NP colloids are inherently difficult to prepare by reducing metal salts with common reducing agents. This study describes the first solution-based synthesis of NiAu alloy NPs by way of a fast butyllithium reduction method. By supporting the particles on SiO2 and subsequent conditioning, one obtains a NiO-stabilized Au NP catalyst that exhibits remarkable resistance to sintering and is highly active for CO oxidation. The active NiO-stabilized Au NP catalyst is prepared by in situ phase transformation of NiAu alloy NPs through an Au@Ni core-shell like NP intermediate. In contrast, the corresponding NiO-free Au NPs prepared by an analogous method show negligible low-temperature catalytic activity and a high propensity for coalescence.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1059305
• Journal Information: ChemPhysChem, Vol. 9, Issue 17; ISSN 1439-4235
• Country of Publication: United States
• Language: English