Vicente Cortés Corberán

Hydrogen from Bioethanol

Bioethanol, ethanol produced from biomass by fermentation, is the most promising renewable source for hydrogen production. Ethanol is advantageous over other conventional substrates because it is readily available, easy to obtain from biomass and to transport, CO 2 neutral and safe to handle. Ethanol is a well-established source of hydrogen by catalytic steam reforming, oxidative reforming or partial oxidation. An efficient catalyst for hydrogen production from ethanol has to dissociate the C–C bond, maintain a low CO concentration and be stable under catalytic operation. Noble metal-based catalysts perform well; they are stable and exhibit high activity. However, they are expensive and need high temperatures to be active. Nickel- and cobalt-based catalysts are inexpensive but under reaction conditions, they suffer from sintering and deactivation by carbon deposition. Supports with redox properties, based on CeO 2 , can oxidize carbon residues and prevent extensive carbon deposition due to its oxygen storage capacity and high oxygen mobility. The use of catalytic membrane reactors, with simultaneous generation and separation of hydrogen, appears as an attractive approach to simplify on-site/on-demand ethanol reformers and to reduce downstream separation costs. Looking for mobile applications, microreactor technologies have been applied to ethanol reforming processes as well. Recently, photocatalytic generation of hydrogen at room temperature from water–ethanol mixtures has been accomplished over noble metals supported over semiconductors.

Novel KF-TiO2catalysts for oxidative dehydrogenation of isobutane

A novel type of catalysts, KF-TiO2, efficient for the oxidative dehydrogenation (ODH) of isobutane is presented. The effect of KF content and calcination temperature was studied. In the reaction conditions explored, the best performance (73 % selectivity to isobutene at 10.5 % conversion of isobutane) was observed over a catalyst with KF/TiO2 = 0.2 (mol/mol). The surface properties of the catalysts were investigated by SPS (Surface Photo-voltage Spectroscopy) and XPS. The promotion effect of KF in the catalysts can be attributed to the formation of an oxyfluoro-compound, K2Ti4O8F2.

Oxidative Dehydrogenation of Propane on Large-Pore Zeolites

Transformation of low molecular weight alkanes to alkenes and aromatics via oxidative and non-oxidative routes presents a major challenge since the implementation of the “Cyclar” process. Catalysts containing ZSM-5 zeolite modified with Ga or Zn species were investigated widely for this purpose [1]. Recently other zeolites (faujasite, ferrierite, Beta) were studied in the title reaction [2,3]. We showed that the already few gallium ions accommodated by the faujasite matrix significantly increase the selectivity to propene [2]. Preliminary results on zeolite Beta modified with Ga- and B-species [3] have also shown that this structure possesses promising activity and selectivity in the oxidative dehydrogenation (ODH) of propane.