NOVELTY - Converting gaseous mixture comprising water and at least one of carbon monoxide and carbon dioxide to hydrocarbons comprises: providing a flow of water and carbon monoxide and carbon dioxide into reaction chamber containing a supported metal catalyst; heating reaction chamber to a temperature greater than 100 degrees C; and exposing the supported metal catalyst to electromagnetic radiation, thus causing a reaction that generates hydrocarbons from the provided flow. The supported metal catalyst comprises a photoactive material support and many conductive particles disposed on the support.    USE - The method is useful for converting gaseous mixture comprising water and at least one of carbon monoxide and carbon dioxide to hydrocarbons.    ADVANTAGE - The method: produces heavier hydrocarbons using single reactor from C1 feedstock and water and renewable sources; is energy efficient; and provides hydrocarbons at yields greater than 100 mu g/g of catalyst per hour and even greater than 200 mu g/g of catalyst per hour and percentage greater than the percentage of methane and/or methanol.    DETAILED DESCRIPTION - INDEPENDENT CLAIM is also included for:    (1) an apparatus (a1) for carrying out thermocatalytic and photocatalytic reactions, comprising a reaction vessel comprising a vessel wall defining a chamber and having a gas inlet and a gas outlet in fluid communication with the chamber, where the reaction vessel is configured to operate at temperatures greater than 100 degrees C and to permit electromagnetic radiation to pass through at least a section of the vessel wall and into the chamber, a packed bed comprising a surface and disposed in the chamber, where disposed on the surface of the packed bed is a supported metal catalyst comprising a photoactive material support and a conductive material interspersed on the support and a gaseous mixture in the chamber consisting essentially of reaction products, water, and at least one carbon monoxide and carbon dioxide, where the chamber is at a temperature greater than 100 degrees C;    (2) an apparatus (a2) for carrying out thermocatalytic and photocatalytic reactions, comprising a reaction vessel comprising a vessel wall defining a chamber and having a gas inlet and a gas outlet in fluid communication with the chamber, a catalytic body comprising a surface and disposed in the chamber, where disposed on the surface of the catalytic body is a solid catalyst;    (3) a solar concentrating system comprising an optical concentrating device, a packed bed reactor configured to receive light from the optical concentrating device, where the reactor comprises a reaction vessel comprising a vessel wall having gas inlet having an inflow and a gas outlet having an outflow, both in fluid communication with the chamber, a packed bed, a gasification unit in fluid communication with the reaction chamber configured to convert liquid water to steam and carbon dioxide supply line in fluid communication with the reaction chamber;    (4) a solid catalyst comprising a photoactive material support having a surface and a conductive material interspersed on the surface of the support, where the conductive material comprises at least one of iron, cobalt, nickel, copper, ruthenium, rhodium, iridium, palladium, platinum or silver;    (5) coupling photochemical water oxidation with carbon dioxide or carbon monoxide reduction and thermochemical carbon-chain formation, comprising providing a flow of at least one of carbon dioxide and carbon monoxide, and water into a reaction chamber containing a supported metal catalyst, heating the reaction chamber to a reaction temperature greater than 100 degrees C and exposing the supported metal catalyst to electromagnetic radiation to cause photochemical water oxidation, carbon dioxide or carbon monoxide reduction, and thermochemical hydrocarbon formation, where the hydrocarbons comprise alkanes and alcohols having at least 2 carbons; and    (6) concentrating solar radiation to provide light for the photochemical excitation of a supported metal catalyst and to provide the thermal energy needed for carbon-chain formation reactions, comprising providing a flow of water and at least one of carbon dioxide or carbon monoxide into a reaction chamber containing a supported metal catalyst comprising a semiconductor, where the pressure in the reaction chamber is 1-15 atm and concentrating and directing solar radiation to the reaction chamber, thus heating the reaction chamber to a reaction temperature greater than 100 degrees C and causing the photochemical excitation of the semiconductor, where hydrocarbons having at least 2 carbons are formed in the reaction chamber.