Mn–Co oxide decorated on Cu nanowires as efficient catalysts for catalytic oxidation of toluene

Abstract

Mn–Co mixed oxides were electrodeposited on Cu nanowires generated on Cu foam (CF) and used for effectively catalytic oxidation of toluene. The physical and chemical properties of the prepared catalysts were characterized by SEM, TEM, XRD, H2-TPR, O2-TPD and XPS. It is found that the Mn–Co mixed metal oxides were uniformly coated on the Cu nanowires by the electrochemical method, whose Mn/Co ratio can be tuned by adjusting the molar ratio of Mn/Co in the initial solution for the electrodeposition. The intimate contact between Mn and Co nanocrystals was found by HRTEM, which is important for realizing synergetic effects on improving catalytic activity. Meanwhile, the formation of the active surface oxygen species and the increase of the active species of Mn4+ and Co3+ were considered to make significant contribution to the catalytic oxidation of toluene. Mn–Co mixed metal oxide catalysts exhibited higher performance than the single metal oxide, and especially 0.10Mn–0.01Co/CF catalyst with the Mn/Co molar ratio of 10:1 in the initial solution for the electrodeposition achieved the highest catalytic activity with a low toluene conversion temperature (T90%) of 251 °C, and displayed excellent catalytic stability even in the presence of water vapor. It is expected that such a simply-electrodeposited mixed metal oxides based catalysts could be applied for the oxidation of volatile organic compounds (VOCs) in a practical process.