Enhanced catalytic performance of Cu- and/or Mn-loaded Fe-Sep catalysts for the oxidation of CO and ethyl acetate

The Fe-modified sepiolite-supported Mn–Cu mixed oxide (CuxMny/Fe-Sep) catalysts were prepared using the co-precipitation method. These materials were characterized by means of the XRD, N2 adsorption–desorption, XPS, H2-TPR, and O2-TPD techniques, and their catalytic activities for CO and ethyl acetate oxidation were evaluated. The results show that catalytic activities of the CuxMny/Fe-Sep samples were higher than those of the Cu1/Fe-Sep and Mn2/Fe-Sep samples, and the Mn/Cu molar ratio had a distinct influence on catalytic activity of the sample. Among the CuxMny/Fe-Sep and Cu1Mn2/Sep samples, Cu1Mn2/Fe-Sep performed the best for CO and ethyl acetate oxidation, showing the highest reaction rate and the lowest T50 and T90 of 4.4×10−6mmol·g−1·s−1, 110, and 140°C for CO oxidation, and 1.9×10−6mmol·g−1·s−1, 170, and 210°C for ethyl acetate oxidation, respectively. Moreover, the Cu1Mn2/Fe-Sep sample possessed the best low-temperature reducibility and the lowest temperature of oxygen desorption as well as the highest surface Mn4+/Mn3+ and Cu2+/CuO atomic ratios. It is concluded that factors, such as the strong interaction between the Cu or Mn and the Fe-Sep support, good low-temperature reducibility, and good mobility of chemisorbed oxygen species, might account for the excellent catalytic activity of Cu1Mn2/Fe-Sep.