Ru-Cu/SiO2 catalysts: Characterization by FTIR spectroscopy

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 asymmetric 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 RUCl(3).