Dehydrogenation reactions of mechanically activated alkali metal hydrides with CO2 at room temperature.

Reactions between alkali metal hydrides MH (M = Li, Na, or K) and carbon dioxide (CO 2 ) at room temperature were systematically investigated for the first time. It was found that the raw alkali metal hydrides did not react with CO 2 under static-pressure conditions at room temperature, but the mechanically activated alkali metal hydrides reacted with CO 2 and released large amounts of hydrogen (H 2 ). Under the same ball-milling conditions, the order of reactivity of the alkali metal hydrides with CO 2 was KH > NaH > LiH. The particle size of the activated alkali metal hydrides had a large influence on the reactivity of the alkali metal hydrides with CO 2 . During the reactions, CO 2 was reduced by alkali metal hydrides, generating elemental carbon, alkali metal oxides and H 2 , and it was consumed by alkali metal oxides, forming carbonates. [ABSTRACT FROM AUTHOR]