CO oxidation over Pd/<img src='/image/spc_char/gamma.gif' border=0>-FeMnO₃ catalyst

Abstract

<img src='/image/spc_char/gamma.gif' border=0>-FeMnO₃ samples with and without Pd metal impregnation have been prepared by co-precipitation method and investigated by powder X-ray diffraction and ⁵⁷Fe Mossbauer spectroscopy techniques, for its bulk characteristics. Catalytic activity of these samples has been studied for CO oxidation reaction by injecting CO or (CO+O₂) pulses over their surface, with a view to delineate the role of Pd metal and reducible cations during this reaction. Pd metal impregnation over the surface of <img src='/image/spc_char/gamma.gif' border=0>-FeMnO₃, leads to significant improvement in its catalytic activity, particularly at lower temperatures. Based on these experiments, clear evidence for the low temperature (T~350 K) disproportionation of CO over the surface of Pd metal particles and lattice oxygen incorporation during CO oxidation reaction, have been presented. From the comparative study of Fe₂O₃, Mn₂O₃ and FeMnO₃, the existence of any synergistic effects between Fe³⁺ and Mn³⁺ cations, is ruled out for FeMnO₃, mixed oxide system.