An integrated process by coupling hydrothermal reactions, including CO2 reduction and H2O dissociation with metals, is proposed. The hydrogen could be rapidly produced under hydrothermal conditions, owing to the special characteristics of high temperature water, generating metal hydrides as intermediates. Hydrogen production from the H2O dissociation under hydrothermal conditions is one of the most ideal processes due to its environmentally friendly impact. Recent experimental and theoretical studies on the hydrothermal reduction of CO2 to value-added products by in situ generated metal hydrides are introduced, including the production of formic acid, methanol, methane, and long-chain hydrocarbons. These results indicate that this process holds promise in respect to the conversion of CO2 to useful chemicals and fuels, and for hydrogen storage, which could help alleviate the problems of climate change and energy shortage.
Keywords: CO2; hydrogen storage; hydrogenation; hydrothermal reduction; metal hydrides.