In situ FT-IR studies on the CO2 hydrogenation over the SiO2-supported RhM(M = Cr, Mo, W) complex catalysts

The in situ FT-IR spectra were used to study the CO2 hydrogenation reaction s over the SiO2-supported heterobinuclear metal complex catalysts, RhM (M = Cr, Mo, W). The bands, which correspond to the formate species adsorbed on the catalysts, were observed. During the hydrogenation reactions, the adso rbed linear and bridged bridging CO were not observed. The experimental res ults suggest that for the CO2 and CO hydrogenation reactions over the same catalysts, their catalytic active intermediate species and the reaction mec hanisms should be different. (C) 2001 Elsevier Science B.V. All rights rese rved.