Oxidized Diamond: Novel Catalyst Support Material for Various Catalytic Reactions

As a new catalyst support, powdered diamond was first investigated. Although diamond has been considered to be a stable material, the surface carbon was found to react to give C-H and C-O-C or C=O bonds by hydrogenation and oxidation. Oxygen treated diamond (O-Dia) was evaluated as a catalyst support material, which was considered to be a pseudo solid carbon oxide phase corresponding to the well known catalyst support SiO2. Following reactions were successfully carried out using O-Dia supported metal oxides or metal catalysts: Dehydrogenation of light alkanes and ethylbenzene to give light alkenes and styrene on Cr2O3 and V2O5/O-Dia catalysts; direct oxidation of C2H6 and CH4 to aldehydes using CO2 as the oxidant over V2O5/O-Dia catalyst; oxidation of methane to syn-gas over Ni or Co/O-Dia catalysts; carbon nanofilament or nanotube synthesis over Ni and Pd/O-Dia catalysts; ammonia synthesis over Ru/O-Dia catalyst. This review article summarizes the characteristics of these reactions.