The effect of copper content on the reactivity of Cu/Co6Al2 solids in the catalytic steam reforming of methane reaction

Abstract

The steam reforming of methane over Cu/Co6Al2 mixed oxides with different copper contents was studied. The Co6Al2 support was prepared via the hydrotalcite route. It was thermally stabilized at 500 °C, impregnated with 5 wt.%, 15 wt.% or 25 wt.% copper using copper (II) nitrate Cu(NO3)2·3H2O precursor and then calcined again at 500 °C under an air flow. The impregnation of copper enhanced significantly the reactivity of the solids in the considered reaction. The 5Cu/Co6Al2 solid was the most reactive one, with a methane conversion of 96% at 650 °C. The selectivities of H2 and CO2 were also better for the catalyst containing 5 wt.% copper compared to higher copper loadings. The decrease in the catalytic reactivity with increasing the copper content was attributed to the formation of agglomerated and less reactive CuO species, which were detected by XRD and TPR analyses.