A decomposition system providing the decomposition of gaseous hydrogen sulfide into hydrogen gas and elementary sulfur, characterized by comprising - at least one pump providing the supply of H 2 S gas from a source into the system in the form of bubbles; - an aqueous acidic phase with a pH below 4, providing the ionization of H 2 S gas in water and comprising at least one redox couple; - and at least one column reactor comprising an organic phase, which is immiscible in aqueous phase, with a density above the density of water and capable to dissolve elementary sulfur, wherein the organic phase stays below the aqueous acidic phase, wherein the aqueous phase and the organic phase do not mix with each other because of density difference and thus form an interface where they contact each other and an oxidation reaction takes place in the interface by which the H 2 S bubbles carried into the organic phase through the pump are converted into elementary sulfur; - at least one cooling unit to which the elementary sulfur generated in the column reactor is transferred and is crystallized to be taken out of the system; - at least one photo-/electrochemical cell, which comprises at least one first chamber comprising at least one anode electrode, at least one second chamber comprising at least one cathode electrode, and at least one membrane separating the first chamber from the second chamber, and to which the aqueous acidic phase in the column reactor is transferred, and in which the oxidation of the redox couple and the reduction reaction of H + to H 2 take place, wherein following the reduction reaction, the aqueous acidic phase is transferred back to the column reactor; - and at least one energy source generating the required potential difference to be conducted to at least one of the electrodes for the oxidation of the redox couple and the reduction reaction of H + to H 2. - at least one pump providing the supply of H 2 S gas from a source into the system in the form of bubbles; - an aqueous acidic phase with a pH below 4, providing the ionization of H 2 S gas in water and comprising at least one redox couple; - and at least one column reactor comprising an organic phase, which is immiscible in aqueous phase, with a density above the density of water and capable to dissolve elementary sulfur, wherein the organic phase stays below the aqueous acidic phase, wherein the aqueous phase and the organic phase do not mix with each other because of density difference and thus form an interface where they contact each other and an oxidation reaction takes place in the interface by which the H 2 S bubbles carried into the organic phase through the pump are converted into elementary sulfur; - at least one cooling unit to which the elementary sulfur generated in the column reactor is transferred and is crystallized to be taken out of the system; - at least one photo-/electrochemical cell, which comprises at least one first chamber comprising at least one anode electrode, at least one second chamber comprising at least one cathode electrode, and at least one membrane separating the first chamber from the second chamber, and to which the aqueous acidic phase in the column reactor is transferred, and in which the oxidation of the redox couple and the reduction reaction of H + to H 2 take place, wherein following the reduction reaction, the aqueous acidic phase is transferred back to the column reactor; - and at least one energy source generating the required potential difference to be conducted to at least one of the electrodes for the oxidation of the redox couple and the reduction reaction of H + to H 2.