Highly Efficient CuO/α-MnO₂ Catalyst\nfor Low-Temperature CO Oxidation

Abstract

Copper manganese\ncomposite (hopcalite) catalyst has been widely\nexplored for low-temperature CO oxidation reactions. However, the\nprevious reports on the stabilization of such composite catalysts\nhave shown that they deactivated severely under moist conditions.\nHerein, we developed an α-MnO₂ nanorod-supported\ncopper oxide catalyst that is very active and stable for the conditions\nwith or without moisture by the deposition precipitation (DP) method.\nIncredibly, the CuO/MnO₂ DP catalyst (with 5 wt % copper\nloading) achieves superior activity with a reaction rate of 9.472\nμmol^–1·g_cat^–1·s^–1 even at ambient temperatures, which is\nat least double times of that for the reported copper-based catalyst.\nAdditionally, the CuO/MnO₂ DP catalyst is significantly\nmore stable than the copper manganese composite catalysts reported\nin the literature under the presence of 3% water vapor as well as\nwithout moisture. A correlation between the catalytic CO oxidation\nactivity and textural characteristics was derived <i>via</i> multitechnique analyses. The results imply that the superior activity\nof the CuO/MnO₂ DP catalyst is associated with the proper\nadsorption of CO on partially reduced copper oxide as Cu­(I)–CO\nand more surface oxygen species at the interfacial site of the catalyst.