  Dehydrogenation of alkanes is of increasing importance in fulfilling global
demand for olefins and offers a potential source of carbon-neutral hydrogen as
a co-product. Currently commercial dehydrogenation processes occur at
high-temperatures (500-900$^\circ$C) which is energy intensive and results in
side reactions and rapid coking of the catalysts. In addition the hydrogen
produced is often burned to maintain temperature and to inhibit the back
reaction. Here we demonstrate pressure as a parameter to enable novel chemical
catalytic processes and demonstrate ambient-temperature dehydrogenation of
alkanes by palladium at 50-100 MPa pressures, with both hydrogen gas and
olefins recovered on decompression. This reaction follows a fundamentally
different path to current commercial high-temperature low-pressure
dehydrogenation processes with the palladium catalyst reversibly forming a
hydride intermediate.
