Adsorption and catalytic reactions of acetonitrile and acetonitrile–oxygen mixture on TiO 2-supported rhodium catalysts

Abstract

The adsorption and surface reactions of acetonitrile and acetonitrile–oxygen gas mixture were studied on TiO 2-supported Rh catalysts at 300–673 K. FTIR spectra show different kinds of molecularly adsorbed CH 3CN; acetonitrile can be bonded to weak Lewis acid sites (2295 cm −1), to strong Lewis acid sites (2319 cm −1), to very strong Lewis acid centres (2347 cm −1) of titania; it can be coordinated linearly through the lone electron pair of the N atom on Rh sites (2193 cm −1) and η 2 (C,N) CH 3CN species can be formed on Rh particles (1691–1708 cm −1). CH 3CN dissociates on Rh sites, the resulting CN (a) can be oxidized into NCO surface species. CN (a) can be dissociated only on Rh particles into N (a) and C (a). The hydrogenation of N (a) resulted in the appearance of NH 3 among the gaseous products from Rh/TiO 2 catalysts. The formation of other products (CH 3NH 2, H 2, CO 2, CH 4, C 2H 4 and CO) was demonstrated and discussed.