Structure and Reactivity of Ni−Au Nanoparticle Catalysts

TLDR: In this paper, the Ni−Au nanoparticle catalyst system is designed based on the detailed experimental and theoretical understanding of the alloying and the chemical reaction processes on single-crystal surfaces.

Abstract: We discuss the design of a Ni−Au nanoparticle catalyst system, which is based on the detailed experimental and theoretical understanding of the alloying and the chemical reaction processes on single-crystal surfaces. The alloy formation and structure of Ni−Au catalysts supported on SiO2 and on MgAl2O4 are simulated by Monte Carlo schemes as well as experimentally studied by a combination of in situ X-ray absorption fine structure, transmission electron microscopy, and in situ X-ray powder diffraction. On-line mass spectrometry is used to follow the reactivity of the catalyst and thermogravimetric analysis provided information on the deposition rate of carbon during steam reforming of n-butane. The simulations and the experiments give evidence for the formation of a Ni−Au surface alloy on the Ni particles for both supports. The Ni−Au catalysts exhibiting the surface alloy are active for steam reforming and are more resistant toward carbon formation than the pure Ni catalyst. Blocking of highly reactive Ni ...