Formula omitted] catalysts: characterization by FT-IR spectroscopy

Abstract

H-ZSM5 supported RuCu bimetallic catalysts have been studied by FT-IR spectroscopy. Experiments have been carried out on samples prepared from Ru(NO)(NO 3) 3 and RuCl 3. On the monometallic Ru ZS M5 samples adsorption of CO led to a band at 2046 cm −1, due to CO linearly adsorbed on Ru 0, and several bands at higher frequencies related to CO on Ru δ+ species. A higher amount of Ru δ+ species is formed on the ex-Ru(NO)(NO 3) 3 sample, due to the smaller metal particle size of this sample compared to the ex-RuCl 3 one. On monometallic Cu ZSM5 two bands at 2151 and 2158 cm −1 are observed, both related to CO adsorbed on Cu +1 sites, formed through a reaction with the OH groups of the zeolite. On the bimetallic RuCu samples, besides all the characteristic bands of the Ru and Cu monometallic samples, a band at 2138 cm −1, attributed to CO adsorbed on Cu bound to Ru has been detected, denoting the formation of RuCu bimetallic particles. The FT-IR spectra indicate that on the samples prepared from RuCl 3 the extent of bimetallic RuCu particles is higher than on those prepared from Ru(NO)(NO 3) 3. This behaviour, attributed to the presence of chlorine on the ex-RuCl 3 samples, is in agreement with the catalytic performance of these systems in the hydrogenolysis of propane.