Effect of MnOx in the catalytic stabilization of Co2MnO4 spinel during the ethanol steam reforming reaction

Co-based spinel-structured Co2MnO4 was assessed as a catalyst for the ethanol steam reforming reaction. Ethanol conversion over spinet-structured Co2MnO4/SBA-15 was comparable to that over CoxOy/SBA-15 and CoxOy/MnxOy/SBA-15 after a reduction treatment. The spinel structure of Co2MnO4 exhibited extremely stable performance until 71 h, whereas the catalytic activities of the CoxOy/SBA-15 and CoxOy/MnxOy/SBA-15 were reduced by carbon deposition involving different reforming mechanisms. The catalytic stability for the reforming reaction was closely related to the stability of the cobalt oxidation states through the assistance of manganese oxides and its spinet structure. The Co2MnO4/SBA-15 exhibited the highest activity for the reforming reaction at 700 degrees C. Cobalt in the spinel structure of Co2MnO4 is believed to make a major contribution to the absolute catalytic activity because there is little or no catalytic deactivation induced by aggregation between their particles compared to the impregnated cobalt ingredients. On the other hand, manganese oxide in the spinel structure of Co2MnO4 was suggested to provide oxygen to the cobalt catalytic active sites, resulting in increases in hydrogen production and the suppression of CO generation. (C) 2015 Elsevier B.V. All rights reserved.