The term “Hydrogen Economy” refers to a forward-looking approach where this gas, synthesized in a clean and economic way, would feed the major part of society energy requirements. This proposal would reduce the present fossil fuel dependence, because hydrogen could be generated from other primary energy sources such as renewable or nuclear. Moreover, both air pollution and greenhouse effect gases emission would decrease, due to the fact that the only product generated by the hydrogen combustion in a fuel cell is water.
	On this context, the present Doctoral Thesis tries to contribute to the energy efficiency improvement and the cost reduction (both installation and operating costs) of alkaline water electrolysis for hydrogen production. This objective has been achieved by means of the development of new electrode materials (cathodes), key components of electrolyzers.
	The most important properties of electrode materials are: large surface area (porosity), strong intrinsic catalytic activity, stability/durability of performance, and low cost. In the present Doctoral Thesis Nickel based porous electrodes have been synthesized by electrodeposition on stainless steel substrates, in order to obtain a material which combines the properties pointed out. The development of a pre-treatment process of the substrates has been necessary to guarantee a good adhesion of the deposited layers. Electrodic materials have been fabricated following different electrodeposition strategies: on the one hand, type Raney materials, characterized by a cracked surface; on the other hand, macroporous materials obtained on gaseous dynamic templates (generated by the application of very high current densities). Following these procedures, Nickel-Cobalt co-depositions have been carried out. These alloys improve, in determined composition ranges, the intrinsic catalytic activity as a consequence of the synergism between the properties of Nickel and Cobalt.
	The developed electrodes have been preliminary characterized by steady-state polarization curves and electrochemical impedance spectroscopy (EIS). EIS permits us to determine the roughness factor of the fabricated cathodes, a key parameter in electrocatalysis. From the obtained results, it has been possible to evaluate the intrinsic and apparent catalytic activities, and the reaction mechanism. Hydrogen evolution reaction (HER) takes place on all the developed electrodes by means of the VolmerHeyrovsky mechanism, being the electrochemical desorption the rate determining step.
	The best electrode materials have been characterized by hydrogen discharge curves and galvanostatic tests. The use of Raney Ni electrodes and Ni-Co electrodes obtained at a high current density (with 42.5 at.% in superficial Co) as cathodes reduces the energetic costs of hydrogen production in a percentage higher than 25%, in the same conditions at which industrial alkaline water electrolysis takes place (i.e. 80°C and the highest overpotentials), in comparison with the smooth commercial Ni cathodes.