%0 Journal Article
%T Zeolites: Promised Materials for the Sustainable Production of Hydrogen
%A Antonio Chica
%J ISRN Chemical Engineering
%D 2013
%R 10.1155/2013/907425
%X Zeolites have been shown to be useful catalysts in a large variety of reactions, from acid to base and redox catalysis. The particular properties of these materials (high surface area, uniform porosity, interconnected pore/channel system, accessible pore volume, high adsorption capacity, ion-exchange ability, and shape/size selectivity) provide crucial features as effective catalysts and catalysts supports. Currently, new applications are being developed from the considerable existing knowledge about these important and remarkable materials. Among them, those applications related to the development of processes with less impact on the environment (green processes) and with the production of alternative and cleaner energies are of paramount importance. Hydrogen is believed to be critical for the energy and environmental sustainability. It is a clean energy carrier which can be used for transportation and stationary power generation. In the production of hydrogen, the development of new catalysts is one of the most important and effective ways to address the problems related to the sustainable production of hydrogen. This paper explores the possibility to use zeolites as catalysts or supports of catalysts to produce hydrogen from renewable resources. Specifically, two approaches have been considered: reforming of biomass-derived compounds (reforming of bioethanol) and water splitting using solar energy. This paper examines the role of zeolites in the preparation of highly active and selective ethanol steam reforming catalysts and their main properties to be used as efficient water splitting photocatalysts. 1. Zeolites: Composition, Structure, Properties, and Applications Zeolites were first described in 1756 by the Swedish mineralogist Cronstedt [1]. However, the systematic research efforts on synthetic zeolites were initiated by Barrer in the late 1930s [2, 3]. Barret offered the first classification of zeolites based on molecular size [4]. Inspired by the work of Barrer, researchers at Union Carbide developed synthesis procedures for preparation of the first synthetic zeolites (i.e., zeolites A, X, and Y) that would find industrial applications [5¨C7]. Initially zeolites were applied as materials for drying and separation substances. Later, with the development of the concept of acid zeolite catalyst, in 1959, they were used as catalysts in the isomerization of hydrocarbons [8]. Previously, Houdry et al. [9] used them in catalytic cracking of hydrocarbons. Since the development of the first concepts, to date many business processes based on zeolites as
%U http://www.hindawi.com/journals/isrn.chemical.engineering/2013/907425/