Ru–Cu/SiO2 catalysts: characterization by FTIR spectroscopy

Abstract

Silica supported Ru–Cu bimetallic catalysts have been studied by FTIR Spectroscopy. Experiments have been carried out on two series of samples prepared from RuCl₃ and Ru(NO)(NO₃)₃. The systems studied contained a total amount of metal of ca. 2 wt.%. On the monometallic Ru/SiO₂ samples, adsorption of CO led to an asymetric band centred at 2036 cm^–1 and two small bands at a higher frequency. The band intensity was greater for the samples prepared from Ru(NO)(NO₃)₃. CO adsorption on Cu/SiO₂, leads to a band at 2117 cm^–1 which easily disappears upon outgassing at room temperature. On the bimetallic samples, the IR spectra indicate the formation Ru–Cu particles having a surface covered mainly by Cu; there is more Cu on the surface of the samples prepared from RuCl₃.