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 ESR reaction.
• The spinel structure of Co2MnO4 exhibited extremely stable performance until 71 h.
• The Co2MnO4/SBA-15 exhibited the highest catalytic activity for ESR at 700 °C.
• Spinel structured-Co2MnO4 is a major contribution to the absolute catalytic activity.
• Manganese oxide in the spinel structure of Co2MnO4 provided oxygen to the cobalt catalytic active sites.

Co-based spinel-structured Co2MnO4 was assessed as a catalyst for the ethanol steam reforming reaction. Ethanol conversion over spinel-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 spinel structure. The Co2MnO4/SBA-15 exhibited the highest activity for the reforming reaction at 700 °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.

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