Catalysis Today 228 (2014) 40–50 Contents lists available at ScienceDirect Catalysis Today j o ur na l ho me page: www.elsevier.com/locate/cattod Effect of lanthanum on the properties of copper, cerium and zirconium catalysts for preferential oxidation of carbon monoxide Jadson Santos Moura a , Juliana da Silva Lima Fonseca a , Nicolas Bion b , Florence Epron b , Tatiana de Freitas Silva c , Cristhiane Guimarães Maciel c , José Mansur Assaf c , Maria do Carmo Rangel a,∗ a GECCAT Grupo de Estudos em Cinética e Catálise, Instituto de Química, Universidade Federal da Bahia, Campus Universitário de Ondina, Federac¸ ão, 40170-280 Salvador, Bahia, Brazil b Université de Poitiers, CNRS UMR7285 Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), 4 rue Michel Brunet, 86022 Poitiers Cedex, France c Universidade Federal de São Carlos, Departamento de Engenharia Química, Via Washington Luiz, km 235, 13565-905 São Carlos, São Paulo, Brazil a r t i c l e i n f o Article history: Received 5 July 2013 Received in revised form 6 November 2013 Accepted 11 November 2013 Available online 12 December 2013 Keywords: Fuel cell CO-PROX Copper Cerium Zirconium Lanthanum a b s t r a c t Catalysts based on copper and cerium oxides are active and selective in preferential oxidation of car- bon monoxide (CO-PROX) and then considered as promising for obtaining hydrogen with acceptable purity for proton exchange membrane fuel cell. However, the low specific surface area of cerium oxide leads to the production of large copper particles, which do not contribute to the catalyst activity. Aiming to find more efficient catalysts for this reaction, the effect of lanthanum on the properties of catalysts based on copper, cerium and zirconium was studied in this work. The samples (CuO–Ce 1−x La x O 2−x/2 and CuO–Ce 0.5−x/2 Zr 0.5−x/2 La x O 2−x/2 ; x = 0.0; 0.05; 0.10) were prepared by precipitation in alkaline medium and heated under air flow at 450 ◦ C. They were characterized by ICP-OES, Fourier transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, specific surface area and porosity measurements, temperature programmed reduction, oxygen storage capacity measurements and isotopic exchange with oxygen-18. The catalysts were evaluated in CO-PROX from 150 to 300 ◦ C. The zirconium-containing sam- ples presented tetragonal structure while the zirconium-free ones showed face-centered cubic structure. Lanthanum and copper were incorporated into ceria lattice, while zirconia and ceria formed solid solu- tions. Zirconium increases the specific surface area by decreasing the particle crystal size and also created mesoporosity. Lanthanum decreased the interaction between copper and ceria while zirconium did the opposite. On the other hand, lanthanum increased the oxygen storage capacity and oxygen mobility whereas zirconium decreased it. Lanthanum did not improve the activity and selectivity of the cata- lysts in CO-PROX. Moreover, zirconium increased the activity, by increasing the interaction between cerium and copper and then increasing the interface where the reaction occurs. All catalysts were resis- tant against deactivation by water and the activity and selectivity could be recovered after poisoning by carbon dioxide. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Over the years, the increasingly search for more efficient and cleaner routes for energy production as well as the concerning for protecting the environment have led to the development of new technologies, such as fuel cells. These devices have been pointed out as the most promising alternatives for the production of electricity in the future [1], especially when fed with hydrogen. Among the several available kinds, the proton exchange membrane fuel cell (PEMFC) is the most advanced one, being able to operate in both mobile and stationary applications [2]. ∗ Corresponding author. Tel.: +55 7133790922; fax: +55 7132374117. E-mail addresses: mcarmov@ufba.br, mcarmog@gmail.com (M.d.C. Rangel). In spite of the high stage of development, there are still some drawbacks to be overcome before the PEMFC can be widely used in commercial applications. One of them is related to the need of using CO-free hydrogen due to the susceptibility of the platinum electro- catalysts to be poisoned by carbon monoxide. Since nowadays most hydrogen is produced by steam reforming of naphtha or natural gas, the purification of the hydrogen-rich stream obtained is required, so that it becomes free or up to about 10 ppm of carbon monoxide [3]. In general, these streams contain around 0.5–2.0% of carbon monoxide [4,5], even after the purification steps by water gas shift reaction over iron based-catalysts at high temperatures [6,7] and then over copper and aluminum-based solids at low temperatures [8,9]. A promising route to purify the hydrogen-rich streams for fuel cells is through the preferential oxidation of carbon monoxide 0920-5861/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.cattod.2013.11.016