Copper Manganese Oxides Supported on Multi-Walled Carbon Nanotubes as an Efficient Catalyst for Low Temperature CO Oxidation

Multi-walled carbon nanotubes (MWCNTs) with unique properties are finding increasing utility in catalytic applications. In this work, Cu-Mn@MWCNTs (copper manganese oxides supported on MWCNTs) was synthesized as an efficient catalyst for low temperature CO oxidation. The catalyst was characterized by N-2 adsorption-desorption, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The CO oxidation activity and long-term working stability of the catalyst were evaluated in 0.1-0.5 % CO and balanced air using a modified fixed-bed reactor. The effects of CO concentration and Cu/Mn molar ratio on the CO oxidation performances were also demonstrated. The increasing CO concentration (0.1-0.5 %) will impair the CO oxidation performances due to the covering of active sites and formation of carbonates and/or hydroxyl species. The increased CO oxidation activity with the changing Cu/Mn molar ratio (1:8-1:1) is ascribed to the improving oxygen utilization in the redox process by increasing Cu content. The synergistic interaction within the Cu-Mn bimetallic catalytic system and the unique properties of the MWCNTs support are also highlighted for the enhanced CO oxidation activity. The catalyst could be considered as a promising option for removing trace CO from typical confined spaces such as space-crafts, submarines and mine refuge chambers.