Abstract: Present invention refers to a device and method for obtaining a mixture of hydrogen Hz and oxygen Oz through the activity of UV radiation on ice microcrystals. The device comprises a source of UV radiation (2); optical fibre (3) via which the UV radiation is directed from the source of the UV radiation (2) towards the chamber (10) containing the ice microcrystals subjected to the activity of the UV rays; internal chamber (6) in which water vapour is introduced via an injector, in which the internal chamber (6) is situated within the chamber (10) from which it is separated by longitudinal barriers (9); a rotating hollow cylinder (5) around whose perimeter fibres (4) are distributed, cooling device (7) that provides ice microcrystals on the fibres (4), where the cooling device (7) is placed within the rotating hollow cylinder (5) and the outflow (8) for the gaseous Oz and Hz towards the feeder.