Study of the activity of Pt-Fe, Pd-Fe and Pt-Cu structured bi-metallic catalysts. Oxidation of VOC: toluene and ethyl acetate

In this work, Pt-Fe and Fe-Cu bi-metallic catalysts supported on monolithic structures composed of a clay mixture with alumina and zeolite FMI (3% Fe), were prepared separately. The incorporation of the metals was carried out using the simultaneous impregnation method in an approximate time of 30 min. then dried in air and calcinated for 4 h at 500°C. The catalysts obtained were used for VOC oxidation. For all catalysts studied, toluene completely oxidized to CO 2 and H 2 O. In the case of ethyl acetate, at relatively low temperatures, partial oxidation products such as ethanol, ethers, acetic acid and acetaldehyde were formed. While oxidation was complete above 280°C. For Pt-Fe catalysts, the influence of the catalytic bed size in the activity was studied. The monolith with the greatest length (6 cm) was the most efficient, reaching toluene conversion > 90%, at elevated flow rate and lower temperatures than those of the remaining catalysts: Pd-Fe and Pt-Cu. The existence of extensive surface zones was determined by the SEM (mapping) technique, where the Pt-Fe and Pd-Fe bi-metallic pair separately, are associated. Iron improves dispersion of Pt microcrystals. XPS results obtained for the Pt-Fe catalyst, indicate an electronic promoter effect between Pt and Fe.