The presence of three transition metal oxides in a nanocomposite made it possible to have higher catalytic CO oxidation than that of two. At higher annealing temperatures, the obtained nanocomposite had more crystallinity and thus exhibited lower activity toward the oxidation of CO. The 50 % CO conversion was observed at about 82 °C for the CuO−MnOx−Fe2O3-300 catalyst.
Abstract
By using a simple co-precipitation method, new Fe2O3-based nanocatalysts (samples) were synthesized. The samples were composites of two or three transition metal oxides, MOx (M=Fe, Mn, Co, Ni, and Cu). The average size of CuO crystallites in the composites composed of two oxide components (CuO−Fe2O3) was about 14.3 nm, while in those composed of three (CuO−MnOx−Fe2O3), the composite's phase compositions were almost in the amorphous form when annealing the sample at 300 °C. The latter sample had a specific surface area higher than that of the former, 207.9 and 142.1 g/m2, respectively, explaining its higher catalytic CO oxidation. The CO conversion over the CuO−MnOx−Fe2O3-300 catalyst (1 g of catalyst, 2600 ppm of CO concentration in air, and 1.0 L/min of gas flow rate) begins at about 40 °C; the temperature for 50 % CO conversion (t 50) is near 82 °C; and CO removal is almost complete at t 99 ≈110 °C. The activity of the optimal sample was tested in different catalytic conditions, thereby observing a high durability of 99–100 % CO conversion at 130 °C. The obtained results were derived from XRD, FTIR, BET, SEM, elemental analysis and mapping, as well as catalytic experiments.
