Hala R. Mahmoud

Effect of Ag-doping of nanosized FeMgO system on its structural, surface, spectral, and catalytic properties

The effects of Ag-doping on the physico-chemical, spectral, surface, and catalytic properties of the FeMgO system with various Fe2O3 loadings were investigated. The dopant (Ag) molar ratio varied between 0.01 % and 0.05 %. The techniques employed for characterisation of catalysts were TG/DTG, XRD, ESR, N2 adsorption at −196°C, and catalytic decomposition of H2O2 at 25–35°C. The results obtained revealed that the investigated catalysts consisted of nanosized MgO as the major phase, apart from the MgFe2O4 and/or Fe3O4 phases. ESR result of the FeMgO system revealed the presence of paramagnetic species as a result of Ag-doping. The textural properties including SBET, porosity and St were modified by Ag-doping. The doping process with Ag-species improved the catalytic activity of the FeMgO system. Increasing the calcination temperature from 400°C to 800°C increased the catalytic activity (k*30 °C) of 0.05 AgFeMgO in H2O2 decomposition by 21.2 times.

Effect of Ag-doping of Nanosized FeAlO System on its Structural, Surface and Catalytic Properties

The effects of Ag2O-doping on the physicochemical, surface and catalytic properties FeAlO system with various extent of Fe2O3 loading have been investigated. The dopant concentration was changed between 1.5 and 4.0 mol % Ag2O. Pure and variously doped solids were subjected to heat treatment at 400-800?C. The techniques employed for characterization of catalysts were TG/DTG, XRD, N2-adsorption at ?196?C and the catalytic decomposition of H2O2 at 25-40?C. The obtained results revealed that, the investigated catalysts consisted of nanosized ?-Al2O3 phase. The textural properties including SBET, porosity and St were modified by Ag2O-doping. The doping process with Ag-species improved the catalytic activity of FeAlO system. Increasing the precalcination temperature from 400 to 800?C increased the catalytic activity (k30°C) of 3.5 % AgFeAlO with 1.9 fold towards H2O2 decomposition. Furthermore, the maximum increase in the k30°C value due to doping with 3.5 mol% Ag2O attained about 15.1 fold for the solids calcined at 800°C.