Preparation Of Heaaluminates Catalysts And Their Catalytic Activity For Methane Combustion

The La-, Ba-hexaaluminate catalysts for high temperature combustion of methane have been prepared using a chemically controlled co-precipitation method and reverse microemulsion method. The effect of Mn- and Fe-substitution on specific surface, structure and catalytic activity for methane combustion was investigated over heaaluminate catalysts through XRD, TPR, XPS, BET and TEM characterization. XRD analysis revealed that the heaaluminate phase was observed when precursors had been calcined at 1200 ℃ for 4 hours. The ion substitute of Mn and Fe can promote the formation of pure single heaaluminate phase, but incorporation of Mn and Fe on excess leads to another phase formation. The specific surface area of catalysts was decrease with the increase of Mn or Fe substitute content. As far as the valence state of transition metal ions is concerned, the introduced Fe ions were always trivalent, whereas the Mn ones were either divalent or trivalent. Activity for methane combustion has been measured for La- and...