A Cobalt Complex of Bis(Methylthioether)Pyridine Catalyst for Hydrogen Evolution from Water

A new cobalt-based catalyst, [(btep)CoBr 2 ] is produced by the reaction of CoBr 2 and bis(methylthioether)pyridine (btep), and its structure has been determined by X-ray crystallography. Our experiments suggest that this cobalt complex can used as a molecular catalyst for electrochemical and photochemical driven hydrogen evolution. As an electrocatalyst, this cobalt complex can provide 591.9 moles of hydrogen per mole of catalyst per hour (mol H 2 /mol catalyst/h) from a neutral water under an overpotential (OP) of 837.6 mV. As a co-catalyst, it was mixed with CdS nanorods (CdS NRs) as a photosensitizer, and ascorbic acid (H 2 A) as a sacrificial electron donor, and [(btep)CoBr 2 ] can provide 9326.4 mol H 2 per mole of catalyst during 40 h irradiation. The highest apparent quantum yield (AQY) is ~25.5%. The catalytic mechanism for H 2 production is investigated by several measurements and analysis.