Abstract
Metal-organic framework (MOF)-derived carbon, which contains metal nanoparticles embedded in a carbon matrix, is becoming an important group of catalysts. We report the synthesis of tungsten carbide-carbon nanocomposites using a similar concept, i.e., by pyrolysis of organotungsten compounds under high-temperature and high-pressure conditions. We characterized the product using various analytical techniques and examined its electrocatalytic activity. Two precursors, Bis(cyclopentadienyl)tungsten (IV) dichloride (Cp(2)WCl(2)) and Bis(cyclopentadienyl)tungsten (IV) dihydride (Cp(2)WH(2)) were pyrolyzed at 4.5 GPa and 600 °C. Tungsten carbide (β-WC(1-x)) crystals with a size of 2 nm embedded in graphitic carbon were formed from Cp(2)WH(2)-derived samples. Electrochemical measurements showed that all samples were active in the oxygen reduction reaction (ORR), with the Cp(2)WH(2)-derived sample having the best catalytic performance.