Effect of ZrO2-doping of nanosized Fe2O3/MgO system on its structural, surface and catalytic properties

Abstract Fe 2 O 3 /MgO system was prepared by wet impregnation method followed by treatment with different amounts of Zr-dopant salt then heating at 500 and 700 °C. The dopant concentrations were 0.48, 0.95 and 1.4 mol% ZrO 2 . Pure and variously doped solids were characterized using XRD, N 2 -adsorption isotherms carried out at −196 °C and catalytic decomposition of H 2 O 2 in aqueous solution at 25–35 °C. The results revealed that the nanosized MgO phase was only detected in the diffractograms of pure and doped solids calcined at 500 °C. Heating pure and doped solids at 700 °C produced nanosized MgFe 2 O 4 phase together with MgO phase. Pure and ZrO 2 -doped solids calcined at 500 and 700 °C are mesoporous adsorbents. The doping process brought about a measurable decrease in the S BET of Fe 2 O 3 /MgO system with subsequent increase in its catalytic activity. The catalytic activity of the investigated system toward H 2 O 2 decomposition, expressed as reaction rate constant per unit surface area was found to increase as a function of dopant concentration. The maximum increase in the reaction rate constant per unit surface area measured for the reaction carried out at 30 °C attained 125% for the heavily doped samples. This significant increase was based on the catalytic activity of pure catalyst sample measured under the same conditions.