Methanol oxidation over copper supported catalysts.

Abstract

Oxidation of methanol has been studied over a range of temperature and contact times with a synthesised, 1wt % copper catalysts supported over Al2O3 and SiO2. Characterisation of these catalysts was performed by nitrogen adsorption and porosity measurements (BET), X-Ray Diffraction (XRD), and IR spectroscopy of adsorbed CO. BET measurement revealed surface areas reducing from 105 to 104 m2g-1 for pure alumina to copper supported catalyst while the silica ones reduced from 247 to 240 m2g-1 for pure silica to the copper supported respectively. Pore sizes also reduced from 32 – 23 nm and 23 – 20.3 nm for the alumina and silica catalysts respectively. No crystalline phases from the diffraction patterns of the loaded metals were found to be present on the XRD. CO adsorption studies showed the presence of small cluster metal atoms adsorbed on the surface of the catalysts with Temperature Programmed Reduction (TPR) experiments revealing the presence of partially oxidised and well dispersed Cu atoms. The alumina supported catalyst were more active than the silica ones while for selectivity and yield for formaldehyde, the reverse was the case. The alumina supported significantly showed high yields of Dimethyl ether (DME) while the silica showed high yield for methyl formate (MF) with COx and CH4 detected in very small quantities.