Abstract
The physicochemical, surface and catalytic properties of pure and doped Fe
2O
3/Al
2O
3 solid catalysts with Au and Mn
2O
3 calcined at 300, 500 and 700
°C were investigated. The dopant concentration of Au was varied between 0.4 and 1.6
mol%, while Mn
2O
3 concentration was varied between 1.0 and 8.0
mol%. The techniques employed were DTA, XRD, TPR, EDX, nitrogen adsorption at −196
°C, CO oxidation by O
2 at 225–275
°C and H
2O
2 decomposition in aqueous solution at 30–50
°C.
The results obtained revealed that the doping of Fe
2O
3/Al
2O
3 solids with different amounts of Au and Mn
2O
3 changed the degree of crystallinity of Al
2O
3 and Fe
2O
3 phases. The doping process led to a progressive increase in the specific surface area of the treated solid catalysts to an extent proportional to the amount of Au and Mn
2O
3 added. This process led also to a progressive increase in the catalytic activities of the investigated solid catalysts towards CO oxidation by O
2 and H
2O
2 decomposition. The doping of solid catalysts with Au calcined at 300, 500 and 700
°C exhibited catalytic activity in CO oxidation by O
2 higher than those measured for solid catalysts doped with Mn
2O
3 calcined at the same temperatures. Opposite results have been observed in case of H
2O
2 decomposition. These findings indicate that the active sites taking part in CO oxidation by O
2 are different from those involved in H
2O
2 decomposition.