H 2 evolution by a cobalt selenolate electrocatalyst and related mechanistic studies.

[Co(bds)(2)][nBu(4)N] (where bds = 1,2-benzenediselenolate) was identified as an electrocatalyst for the hydrogen evolution reaction. Mechanistic studies indicated that a black precipitate, which formed upon treating [Co(bds)(2)](-) with acid, aswell as the one-electron reduced species, [Co(bds)(2)](2-) , were viable catalytic intermediates. We propose two kinetically-competent pathways for H-2 evolution: EC and CE (E = electrochemical, C = chemical step).