Abstract

Two different series of titania-supported iron catalysts prepared by the sol-gel method have been characterised and tested in the combustion of methane at atmospheric pressure. In each series, the effect of metal loading (1,5 and 10 wt%) and gelation pH (3 and 9) were studied. Characterisation data of calcined catalysts, carried out by specific area measurement, TPR, X-ray diffraction, XPS and EPR revealed no significant changes in metal dispersion. The catalytic activity of the solids were evaluated in the combustion of methane under stoichiometric mixture of CH4/O2 from 473 K up to the temperature required for total combustion. The best performance was shown by catalysts having 5 wt. %, which is ascribed to a balance of factors like the presence of a sufficient concentration of iron at the surface, achievement of relatively high dispersion state for iron and the presence of Fe+3 ions incorporated to the lattice of titania.