Photocatalytic water-splitting processes are described using an aqueous solution of at least one neutral salt, where the process is conducted at a temperature of 200-400 C. When compared with conventional photocatalytic water-splitting processes, the processes of the invention give rise to notably increased activity and quantum efficiency.

A photocatalytic device includes a substrate and an array of conductive projections supported by the substrate and extending outward from the substrate. Each conductive projection of the array of conductive projections has a semiconductor composition configured for charge carrier generation in response to solar radiation. Each conductive projection of the array of conductive projections is decorated with a co-catalyst arrangement. The co-catalyst arrangement includes gold and an oxide material.

A device (1) and method are claimed for converting thermal energy into dissociation energy of molecules of a gas medium (3). The device incorporates a reaction vacuum chamber (2), designed to enable a gas medium (3) to be supplied therein, at least one thermal radiator (4), of which at least one emission spectral line of a medium (5), in the temperature range 350 C. to 1500 C., at least partially corresponds to the absorption spectral line of molecules of the gas medium (3). At least part of the volume of the vacuum chamber (2) is positioned in the zone of optical visibility of the radiator (4) and is a reaction volume (7) for the gas medium (3), in which reaction volume, as a result of resonance oscillations of molecules of the gas medium (3), excited by the radiator (4), at least partial dissociation of the gas medium (3) takes place. The device also incorporates a system (8) for drawing off at least one product of dissociation of molecules of the gas medium (3).

The present invention relates to a method and device for producing hydrogen by dissociating the water molecule through thermochemical reactions, using a small amount of active material. The thermochemical reactions are induced by solar energy with a moderate concentration of up to 50 suns, which can be achieved through linear or parabolic concentrators.