Cobalt-Bisglyoximato Diphenyl Complex as a Precatalyst for Electrocatalytic H₂ Evolution

Electrochemical investigation of the title Co II compound in acetonitrile with a strong acid (HClO 4 ) showed no sign of proton catalysis at the Co II /Co I wave, but instead revealed the formation of Co based nanoparticles at the surface of the carbon electrode. Catalytic proton reduction of the resulting nanometer sized cobalt particles at pH 7 was found to occur efficiently. Partial coverage of the carbon substrate by the particles leads to an apparent exchange current density as high as those obtained at a pure cobalt electrode or cobalt films.