NOVELTY - Process-1 comprises contacting a metal-solute species with a catalyst, where the contacting of the catalyst with the metal-solute species forms molecular oxygen and a reduced form of the metal-solute species.    USE - The processes are useful for generating hydrogen and/or oxygen from water.    ADVANTAGE - The process for generating hydrogen and/or oxygen from water requires only water and/or light, and is substantially free of expensive sacrificial reagents, high temperatures and/or pressures, and/or large electrical over potentials.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) a process-2 comprising applying electromagnetic energy having a wavelength of 25-1000 nm to a metal-solute solution to form molecular hydrogen and an oxidized form of the metal-solute solution, where at least some of the electromagnetic energy is absorbed by the metal-solute solution;    (2) a process-3 comprising contacting, in a first compartment, a first metal-solute species with a catalyst, where the contacting of the first metal-solute species with the catalyst forms molecular oxygen and a second metal-solute species, the first metal-solute species is an oxidized form of the second metal-solute species, contacting, in a second compartment containing, photons with the second metal-solute species, where at least some of the photons are absorbed by the second metal-solute species to form hydrogen gas and the first metal-solute species, providing the second metal-solute species formed in the first compartment to the second compartment and providing the first metal-solute species formed in the second compartment to the first compartment; and    (3) a process-4 comprising contacting, in a first compartment, a cerium (IV)-containing sulfonate aqueous solution with a catalyst, where the contacting of the cerium (IV)-containing sulfonate solution with the catalyst forms oxygen gas and cerium (III), providing, in a second compartment, photons having a wavelength of 200-300 nm to a cerium (III)-containing sulfonate aqueous solution, where at least some of the photons are absorbed by the cerium(III)-containing sulfonate solution to form hydrogen gas and cerium (IV), providing the cerium (III) formed in the first compartment to the second compartment and providing the cerium (IV) formed in the second compartment to the first compartment.