NOVELTY - A composition comprises a first component capable of reversible catalytic hydrogenation and dehydrogenation, and a second component having an at least partially selectively oxidizable functional group by air or oxygen.    USE - As a composition for generating heat and for storage and release of hydrogen (claimed) useful in fuel cells or internal combustion engines.    ADVANTAGE - The composition generates hydrogen from a storage medium, with no or relatively small external input of heat.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) releasing hydrogen involving: contacting the composition with at least one catalyst under conditions sufficient to release hydrogen from the composition; contacting at least partially dehydrogenated composition under selective oxidation conditions with at least one catalyst to generate heat; and recovering the heat to provide at least part of the heat required to release the hydrogen;    (2) storing and releasing hydrogen involving: providing the composition; contacting the composition with at least one catalyst under conditions sufficient to release hydrogen from the composition; contacting the partially dehydrogenated composition under selective oxidation conditions with at least one catalyst to generate heat; recovering the heat to provide at least part of the heat required to release the hydrogen; and converting the partially dehydrogenated and selectively oxidized carrier to the composition via at least one catalytic hydrogenation processes; and    (3) releasing hydrogen and generating heat involving: providing a composition comprising a reversibly hydrogen reactive carrier having oxidizable functional groups; contacting the composition under selective oxidation conditions with at least one catalyst to generate heat; contacting the composition with at least one catalyst tinder conditions sufficient to release hydrogen from the composition; and recovering the heat to provide at least part of the heat required to release the hydrogen.