Alumina Supported Copper-Manganese Catalysts for Combustion of Exhaust Gases: Catalysts Characterization

In recent research copper and manganese systems were found to be the most active in CO and organic compounds oxidation among the base catalysts. The mixed copper manganese oxide has been widely studied in oxidation reactions because of their higher activity at low temperatures in comparison with single oxide catalysts. The results showed that the formation of spinel CuxMn3−xO4 in the oxidized catalyst is responsible for the activity even at room temperature. That is why the most of the investigations are focused on the hopcalite catalyst (CuMn2O4) as the best coppermanganese catalyst. Now it’s known that this is true only for CO oxidation, but not for mixture of CO and VOCs. The purpose of this study is to investigate the alumina supported copper-manganese catalysts with different Cu/Mn molar ratio in terms of oxidation of CO, methanol and dimethyl ether. The catalysts were prepared by impregnation of γ-Al2O3 with copper and manganese nitrates and the catalytic activity measurements were carried out in two stage continuous flow equipment with an adiabatic reactor for simultaneous oxidation of all compounds under the conditions closest possible to the industrial. Gas mixtures on the input and output of the reactor were analyzed with a gas chromatograph, equipped with FID and TCD detectors. The texture characteristics were determined by low-temperature (- 196oС) nitrogen adsorption in a Quantachrome Instruments NOVA 1200e (USA) specific surface area & pore analyzer. Thermal, XRD and TPR analyses were performed. It was established that the active component of the mixed Cu- Mn/γ–alumina catalysts strongly depends on the Cu/Mn molar ratio. Highly active alumina supported Cu-Mn catalysts for CO, methanol and DME oxidation were synthesized. While the hopcalite is the best catalyst for CO oxidation, the best compromise for simultaneous oxidation of all components is the catalyst with Cu/Mn molar ratio 1:5.

Authors:

• Krasimir I. Ivanov
• Elitsa N. Kolentsova
• Dimitar Y. Dimitrov
• Georgi V. Avdeev
• Tatyana T. Tabakova

Keywords:

• Supported copper-manganese catalysts
• CO and VOCs oxidation.

References:

[1] C. Jones, K. J. Cole, S. H. Taylor, M. J. Crudace, G. J. Hutchings,
“Copper manganese oxide catalysts for ambient temperature carbon
monoxide oxidation: Effect of calcination on activity”, Journal of
Molecular Catalysis A: Chemical, Volume 305, Issues 1–2, pp. 121–
124, June 2009.
[2] G. J. Hutchings, A. A. Mirzaei, R. W. Joynerb, M. Siddiqui, S. H.
Taylor, “Effect of preparation conditions on the catalytic performance of
copper manganese oxide catalysts for CO oxidation”, Applied Catalysis
A: General 166, pp. 143-152, 1998.
[3] J. Papavasiliou, G. Avgouropoulos, T. Ioannides, “Combined steam
reforming of methanol over Cu–Mn spinel oxide catalysts”, Journal of
Catalysis, Vol. 251, pp. 7–20, October 2007.
[4] Y. Ren, Z. Ma, L. Qian, S. Dai, H. He, P.G. Bruce, “Ordered Crystalline
Mesoporous Oxides as Catalysts for CO Oxidation”, Catal. Lett., Vol.
131, pp. 146–154, 2009.
[5] M. Morales, L. Barbero, L. Cadús, “Combustion of volatile organic
compounds on manganese iron or nickel mixed oxide catalysts”, Applied
Catalysis B: Environmental, Vol. 67, Issues 3–4, pp. 229–236, 2006.
[6] Y. Hasegawa, K. Fukumoto, T. Ishima, H. Yamamoto, M. Sano, T.
Miyake, “Preparation of copper-containing mesoporous manganese
oxides and their catalytic performance for CO oxidation”, Appl. Catal.
B: Environ., Vol. 89, pp. 420–424, 2009.
[7] S. Vepřek, D. L. Cocke, S. Kehl, H.R. Oswald, “Mechanism of the
deactivation of Hopcalite catalysts studied by XPS, ISS, and other
techniques”, Journal of Catalysis, Vol. 100, Issue 1, pp. 250–263, 1986.
[8] M. Kramer, T. Schmidt, K. Stowe, W. F. Maier, “Structural and catalytic
aspects of sol–gel derived copper manganese oxides as low-temperature
CO oxidation catalyst”, Applied Catalysis A: General, Vol. 302, pp.
257–263, 2006.
[9] P. Larsson, A. Andersson, “Oxides of copper, ceria promoted copper,
manganese and copper manganese on Al2O3 for the combustion of CO,
ethyl acetate and ethanol”, Applied Catalysis B: Environmental, Vol. 24,
pp. 175–192, 2000.
[10] S. Kanungo, “Physiochemical properties of MnO2 and MnO2-CuO
and their relationship with the catalytic activity for H2O2 decomposition
and CO oxidation”, J. Catal., Vol. 58, pp. 419-435, 1979.
[11] A. Cremona, C. Rubini, and E. Vogna, “Oxidation catalysts”,
EP1197259 (A1), 2002.
[12] K. Ivanov, “Oxide catalyst for purifying exhaust gases and method of
obtaining it”, BG Patent 66069 (B1), 2011.
[13] K. Ivanov, E. Kolentsova, D. Dimitrov, “Alumina Supported Coppermanganese
Catalysts for Combustion of Exhaust Gases: Effect of
Preparation Method”, XIII International Conference on Chemical
Engineering and Technology, 2015, submitted for publication.
[14] K. Ivanov, D. Dimitrov, B. Boyanov, “Deactivation of Cu - Cr/γ-
alumina catalysts for combustion of exhaust gases”, World Academy of
Science, Engineering and Technology, Volume 5, pp. 270 – 276, 2011.
[15] Z. Ding, W. Martens, R. L. Frost, “Thermal activation of copper nitrate”,
J. of Mat. Sci. Letters, Vol.21, pp. 1415-1417, 2002.
[16] S. A. Kondrat, T. E. Davies, Z. Zu, P. Boldrin, J. K. Bartley, A. F.
Carley, S. H. Taylor, M. J. Rosseinsky, G. J. Hutchings, “The effect of
heat treatment on phase formation of copper manganese oxide: Influence
on catalytic activity for ambient temperature carbon monoxide
oxidation”, Journal of Catalysis, Vol. 281, pp. 279–289, 2011.
[17] P. Wei, M. Bieringer, L.M. D. Cranswick, and A. Petric, “In situ hightemperature
X-ray and neutron diffraction of Cu–Mn oxide phases”, J.
Mater. Sci., Vol. 45, pp. 1056–1064, 2010.
[18] X. Li, J. Xu, L. Zhou, F. Wang, J. Gao, C. Chen, J. Ning, H. Ma,
“Liquid-phase oxidation of toluene by molecular oxygen over copper
manganese oxides”, Catalysis Letters, Vol. 110, 1–2, pp. 149-154, 2006.
[19] Y. Tanaka, T. Utaka, R. Kikuchi, T. Takeguchi, K. Sasaki, and K.
Eguchi, “Water gas shift reaction for the reformed fuels over Cu/MnO
catalysts prepared via spinel-type oxide”, Journal of Catalysis, Vol. 215,
pp. 271-278, 2003.