Study of Ce-Zr-Co fluorite-type oxide as catalysts for hydrogen production by steam reforming of bioethanol

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, Ce2Zr1.5Co0.5O8−δ, 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.