In situ Fourier-transform infrared study of CO–H2 reactions over Rh/Al2O3 catalysts at high pressure and temperature

Abstract

Infrared spectra are reported of methanol and ethanol adsorbed on Rh/Al₂O₃ at 473 K, and of the adsorbed products of the reaction of CO(1 MPa)–H₂(2MPa) over alumina and Rh/Al₂O₃ at 553 K. Catalysis by rhodium leads to production of methanol and ethanol over Rh/SiO₂, but the alcohols interact further with the alumina support in Rh/Al₂O₃ to give surface methanoate and ethanoate anions. Methanoate species are also formed from CO–H₂ over alumina alone in the absence of rhodium. Rh/Al₂O₃ showed a higher selectivity towards methane than Rh/SiO₂ possibly via the involvement of methanoate as an intermediate species.