NOVELTY - The invention relates to an electrocatalytic system for producing hydrogen or liquid hydrocarbons which is then used as fuel for supplying an engine or an energy-producing installation. According to the invention, the system comprises a body (1) with a cylindrical vessel-type structure manufactured from plastic material, having an upper cover (11) wherein there are provided some tubular pipe fittings (a and b) for supplying with water and discharging the hydrogen, and also another coupling for the connection to a direct current source allowing at the same time a module (5) for generating the hydrogen to be fastened in an enclosure (E), said module having a cylindrical structure and being provided with a lower and an upper cover (3 and 9) and having a stainless steel gauze (c) as a lateral surface, and having, at its ends, a disk-shaped electrode (4 and 4') manufactured from complex metal carbide, electrically insulated from the rest of the enclosure (E) and provided with a contact for being coupled to a source of direct contact: some lower and upper contacts (2 and 3) and an electrical contact (6) for the lateral surface (c) and a charge of granular activated carbon which fills the inner of the above-mentioned enclosure (E), another cylindrical vessel (F) manufactured of plastic material, inserted into the water circuit of the body (1), the water from inside the vessel playing the role of a liquid membrane for coarsely separating the generated hydrogen, a polymer membrane (G) with great selectivity for hydrogen which is installed in the upper cover (11) of the water-containing vessel (F) for the purification of the generated hydrogen, a conduit (J) for conveying the generated hydrogen to a pump (D) for the circulation of the water in hydrogen-generating system and an electronic system for adjusting the potential of electrodes and for changing intermittently the polarity thereof, and also for adjusting the water flow rate or for adapting the hydrogen amount generated upon request by a consumer and a source of direct current (A).