Adsorption and oxidation of carbon monoxide on Au and Ni nanoparticles deposited on Al2O3 by laser electrodispersion

Abstract

Dissociative adsorption of CO on Au and Ni nanoparticles deposited on Al2O3 by laser electrodispersion (LED) was for the first time observed using diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. The average particle size was 4.0 nm for the Au nanoparticles and 1.5–2.0 nm for the Ni nanoparticles. The process on alumina-supported Au nanoparticles of similar size, prepared by ion exchange proceeds with lower efficiency. The Ni/Al2O3 catalyst prepared by LED exhibits unusually high activity in the oxidation of CO at T > 600 K. When the catalyst was reused, the temperature of CO oxidation decreased to 450 K. The activity of the Au- and Ni-catalysts prepared by LED is higher than that of the catalysts of identical composition prepared by traditional methods, namely, ion exchange and impregnation. The DRIFT and X-ray photoelectron spectroscopy (XPS) data are used to analyze the structure of the catalysts prepared by LED that is associated with specific features of their adsorption and catalytic properties.