Study of Ce-Zr-Co fluorite-type oxide as catalysts for hydrogen production by steam reforming of bioethanol Julio Ce ´sar Vargas a,b, * , Suzanne Libs b , Anne-Ce ´cile Roger b , Alain Kiennemann b a Departamento de Ingenierı ´a Quı ´mica, Universidad Nacional de Colombia, Ciudad Universitaria, Avenida Carrera 30 N8 45-03, Edificio 453, Bogota ´ D.C., Colombia b Laboratoire des Mate ´riaux, Surfaces et Proce ´de ´s pour la Catalyse LMSPC, UMR CNRS 7515 ECPM, Universite ´ Louis Pasteur, 25 rue Becquerel, 67087 Strasbourg Cedex 2, France Available online 24 August 2005 Abstract Bioethanol, obtained by biomass fermentation, could be an important hydrogen supplier as a renewable source. The development of active, selective and stable catalysts for bioethanol steam reforming is a key point. In this work, a fluorite type Ce-Zr-Co oxide, Ce 2 Zr 1.5 Co 0.5 O 8d , is studied for hydrogen production by steam reforming of ethanol/water mixture and bioethanol solution. The catalyst is characterized before and after catalytic test by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy with energy dispersive X-ray spectroscopy (TEM-EDX). The preparation method based on propionate polymerization in solution ensures the insertion of cobalt in the mixed oxide lattice and provides high micro-homogeneity at nanoscale level. The reduction procedure to activate the catalysts is controlled by thermo programmed reduction (TPR). The partially reduced Ce-Zr-Co oxide catalyst presents high ethanol conversion and high hydrogen selectivity. Superior alcohols (fusel oils) arising from the fermentation process do not influence the catalytic behavior compared to a model ethanol/water mixture. Decreasing activity is related to the formation of carbon filaments, evidenced by thermo programmed oxidation (TPO) measurements and transmission electron microscopy. # 2005 Elsevier B.V. All rights reserved. Keywords: Hydrogen; Bioethanol; Steam reforming; Fluorite; Ce-Zr-Co 1. Introduction As a consequence of the more and more stringent environmental standards and of the decline of the fossil fuels reserves, the growing energy demand has to be supplied from renewable and sustainable, efficient and cost-effective, convenient and safe energy systems [1]. Bioethanol, produced by biomass fermentation, has a great potential for the production of hydrogen and energy. The design of an active, selective and stable catalytic system for the steam reforming of ethanol is one of the key points. The catalyst has to optimize the hydrogen production and to discourage the by-products formation. Various catalysts are studied for the reaction of ethanol steam reforming: oxides [2], oxide-supported transition metals [3–7] or noble metals [8,9]. Among the reported catalysts, the cobalt-based systems seem to be the most promising. They are generally prepared by impregnation of various supports [4,5,7]. The catalysts deactivation is attributed to carbon formation and deposition [3,5,6]. The metal-oxide interaction, which appears as essential for the stability, and the understanding of the active phase are reported only recently [5,10]. The studies of the ethanol steam reforming are not systematically carried out under realistic reaction conditions as regards the ethanol/water ratio as well as the ethanol composition. www.elsevier.com/locate/cattod Catalysis Today 107–108 (2005) 417–425 * Corresponding author. E-mail addresses: jcvargass@unal.edu.co, vargasjc@ecpm.u-strasbg.fr (J.C. Vargas). 0920-5861/$ – see front matter # 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.cattod.2005.07.118