A method of synthesizing a metal foam of at least one metal M having a porous micrometric structure, the method including a step of contact glow discharge electrolysis in an electrolytic plasma reduction conducted in an electrolytic solution in which are immersed an anode and a cathode connected to a continuous electrical power supply, the electrolytic solution including at least one first electrolyte in a solvent, the first electrolyte being the at least one metal M in cationic form, the electrolytic solution further including a gelatine, as well as a metal foam obtained by this method, and a device comprising such a foam.