TY - JOUR
T1 - Preferential oxidation of CO in excess of H2 on Pt/CeO2-Nb2O5 catalysts
AU - Jardim, E. O.
AU - Rico-Francés, S.
AU - Coloma, F.
AU - Anderson, J. A.
AU - Ramos-Fernandez, Enrique V.
AU - Silvestre-Albero, J.
AU - Sepúlveda-Escribano, A.
N1 - The authors gratefully acknowledge the financial support from the MINECO (Spain, Project MAT2010-21147) and Generalitat Valenciana (PROMETEO/2009/002–FEDER and PROMETEOII/2014/004–FEDER). EVRF thanks the MINECO for his Ramón y Cajal Fellowship RYC-2012-11427. EOJ thanks the CNPq – Brazil for her grant. We thank Drs. S.B. Campbell and F.M. McKenna, University of Aberdeen for assistance in performing the DRIFT experiments.
PY - 2015/2/25
Y1 - 2015/2/25
N2 - A series of CeO2 -Nb2 O5 mixed oxides with different Nb content, as well as the pure oxides, have been synthesized by co-precipitation with excess urea. These materials have been used as supports for platinum catalysts, with [Pt(NH3) 4](NO3)2 as precursor. Both supports and catalysts have been characterized by several techniques: N2 physisorption at 77 K, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, UV-vis spectroscopy, scanning electron microscopy, transmission electron microscopy, temperature-programmed reduction and temperature-programmed desorption (CO and H2), and their catalytic behaviour has been determined in the PROX reaction, both with an ideal gas mixture (CO, O2 and H2) and in simulated reformate gas containing CO2 and H2O. Raman spectroscopy analysis has shown the likely substitution of some Ce4+ cations by Nb5+ to some extent in supports with low niobium contents. Moreover, the presence of Nb in the supports hinders their ability to adsorb CO and to oxidize it to CO2. However, an improvement of the catalytic activity for CO oxidation is obtained by adding Nb to the support, although the Pt/Nb2O5 catalyst shows very low activity. The best results are found with the Pt/0.7CeO2-0.3Nb2O5 catalyst, which shows a high CO conversion (85%) and a high yield (around 0.6) after a reduction treatment at 523 K. The effect of the presence of CO2 and H2O in the feed has also been determined.
AB - A series of CeO2 -Nb2 O5 mixed oxides with different Nb content, as well as the pure oxides, have been synthesized by co-precipitation with excess urea. These materials have been used as supports for platinum catalysts, with [Pt(NH3) 4](NO3)2 as precursor. Both supports and catalysts have been characterized by several techniques: N2 physisorption at 77 K, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, UV-vis spectroscopy, scanning electron microscopy, transmission electron microscopy, temperature-programmed reduction and temperature-programmed desorption (CO and H2), and their catalytic behaviour has been determined in the PROX reaction, both with an ideal gas mixture (CO, O2 and H2) and in simulated reformate gas containing CO2 and H2O. Raman spectroscopy analysis has shown the likely substitution of some Ce4+ cations by Nb5+ to some extent in supports with low niobium contents. Moreover, the presence of Nb in the supports hinders their ability to adsorb CO and to oxidize it to CO2. However, an improvement of the catalytic activity for CO oxidation is obtained by adding Nb to the support, although the Pt/Nb2O5 catalyst shows very low activity. The best results are found with the Pt/0.7CeO2-0.3Nb2O5 catalyst, which shows a high CO conversion (85%) and a high yield (around 0.6) after a reduction treatment at 523 K. The effect of the presence of CO2 and H2O in the feed has also been determined.
KW - Ceria
KW - DRIFT
KW - Niobia
KW - Platinum
KW - PROX
UR - http://www.scopus.com/inward/record.url?scp=84921650751&partnerID=8YFLogxK
U2 - 10.1016/j.apcata.2014.12.032
DO - 10.1016/j.apcata.2014.12.032
M3 - Article
AN - SCOPUS:84921650751
VL - 492
SP - 201
EP - 211
JO - Applied Catalysis A: General
JF - Applied Catalysis A: General
SN - 0926-860X
ER -