Abstract: Water is fed into a high temperature pressurized vessel containing hydrated zeolite material loaded with a metal cation in its highest oxidation state. The high temperature causes an endothermic redox reaction to occur that produces oxygen gas and, as a solid reaction product, hydrated zeolite material containing the metal cation in a lower oxidation state and protons. The solid reaction product is passed through a heat exchanger, where it is cooled, and then into a second pressurized reaction vessel at low temperature. Carbon dioxide is fed into the low temperature reaction vessel whereby an exothermic redox reaction occurs that produces a mixture of hydrocarbons and water and that oxidizes the cation back to its highest oxidation state. The oxidized-cation containing hydrated zeolite material generated in the second reaction vessel is passed through the formentioned heat exchanger, where it is heated, and then passed back to the first reaction vessel for recycling.

Abstract: Water is fed into a high temperature pressurized vessel containing hydrated large-port mordenite having a high Si/Al ratio and containing a cation that is selected from a specified group of metals and that is in its highest oxidation state. The high temperature causes an endothermic redox reaction that produces oxygen gas and, as a solid reaction product, a large-port mordenite wherein the metal cation is in a lower oxidation state. The solid reaction product is passed through a heat exchanger, where it is cooled and then into a second pressurized reaction vessel at low temperature whereby there occurs an exothermic redox reaction that produces hydrogen gas and which oxidizes the cation back to its highest oxidation state. The large-port mordenite generated in the second reaction vessel is passed through the heat exchanger, where it is heated, and then back into the first reaction vessel for recycling.

Abstract: A process is disclosed which produces hydrogen and oxygen from water by means of a multi-step, closed, thermochemical cycle. Hydrogen and oxygen are produced at separate stations. Hydrogen and a halogen are produced by a sub-cycle involving transition metal or lanthanide compounds (depending on the halogen) and a hydrogen halide. Oxygen and the hydrogen halide are produced in a sub-cycle involving magnesium or transition metal compounds (depending on the halogen), the halogen and water. When the halogen is chlorine the transition metals in the oxygen producing sub-cycle can be nickel, cobalt, or yttrium and the lanthanide metals in the hydrogen producing sub-cycle can be samarium, europium, or ytterbium. When the halogen is bromine, the metals in the oxygen producing sub-cycle can be manganese or cobalt and the metals in the hydrogen producing sub-cycle can be vanadium or chromium.