Gold nanoparticles supported on soda-lime glass exhibit a photochemical water splitting activity under infrared femtosecond laser excitation. Both H-2 and hydroxyl radicals productions were characterized. The hydroxyl radicals production mechanism was identified by comparison with three prototypal mechanisms, photoionization of organic compound in the UV, VUV dissociation of water and water gamma radiolysis. The mechanisms involved in the case of laser femtosecond seem to be water ionization events occurring at distance from the gold particles. (C) 2012 Elsevier B.V. All rights reserved.