Abstract: The present invention relates to the conversion of water into hydrogen and oxygen, and more particularly to a conversion of water into hydrogen and oxygen using sunlight and an inorganic catalyst. More specifically, the invention relates to systems and processes for generating hydrogen molecules from sunlight and water, such as a process comprising the steps of: i) contacting the water with nanoparticles of an inorganic photocatalyst compound in a reaction zone of a reaction chamber; ii) concentrating sunlight with an optical intensifier such that the intensity is increased by a factor greater than 2; iii) heating the reaction zone to one or more reaction temperatures greater than 140° C.