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4268119 
Journal Article 
Unexpected stability of CuO/Cryptomelane catalyst under Preferential Oxidation of CO reaction conditions in the presence of CO2 and H2O 
Davo-Quinonero, A; Lozano-Castello, D; Bueno-Lopez, A 
2017 
Yes 
Applied Catalysis B: Environmental
ISSN: 0926-3373 
217 
459-465 
WOS:000405158000046 
The catalytic activity of CuO/Cryptomelane for the preferential oxidation of CO in H-2-rich streams has been studied in the absence and presence of H2O and CO2, paying special attention to the catalyst stability and to changes on its physical-chemical properties under CO-PROX reaction conditions.



For fresh CuO/cryptomelane catalyst, the presence of CO2 and/or H2O in the CO-PROX feed partially inhibits CO oxidation due to chemisorption of H2O and CO2 on the catalyst. H2O chemisorption on CuO/Cryptomelane is stronger than CO2 chemisorption, and simultaneous CO2 and H2O adsorption has a synergetic effect that enhances co-adsorption and significantly hinders CO oxidation.



On the contrary, the presence of CO2 + H2O in the CO-PROX reaction mixture has a positive effect in the CuO/Cryptomelane stability upon several consecutive reaction cycles in the 25-200 degrees C range. XRD showed that chemisorbed CO2 + H2O species partially prevent the catalyst deactivation due to cryptomelane reduction to hausmannite (Mn3O4) under the strongly reductive environment of the CO-PROX reaction, and H-2-TPR and Raman spectroscopy characterisation support that the cryptomelane structure is less damaged under CO-PROX conditions in the presence of CO2 and H2O than in the absence of these species. Therefore, interestingly under CO2+ H2O environment (realistic CO-PROX conditions) CuO/Cryptomelane catalyst performs an improved catalytic activity. (C) 2017 Elsevier B.V. All rights reserved. 
PROX; Copper; Cryptomelane; CO oxidation; H-2 purification; PEMFC