Rapid water reduction to H2 catalyzed by a cobalt bis(iminopyridine) complex.
A cobalt bis(iminopyridine) complex is a highly active electrocatalyst for water reduction, with an estimated apparent second order rate constant k(app) ≤ 10(7) M(-1)s(-1) over a range of buffer/salt concentrations. Scan rate dependence data are consistent with freely diffusing electroactive species over pH 4-9 at room temperature for each of two catalytic reduction events, one of which is believed to be ligand based. Faradaic H(2) yields up to 87 ± 10% measured in constant potential electrolyses (-1.4 V vs SCE) confirm high reactivity and high fidelity in a catalyst supported by the noninnocent bis(iminopyridine) ligand. A mechanism involving initial reduction of Co(2+) and subsequent protonation is proposed.
Department of Chemistry, California Institute of Technology, Pasadena, California 91125, United States.
Bryan D
BD
Stubbert
Jonas C
JC
Peters
Harry B
HB
Gray
D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010084:Oxidation-Reduction; D011725:Pyridines / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
D009942:Organometallic Compounds; D011725:Pyridines; D014867:Water; D003035:Cobalt; D006859:Hydrogen