Photocatalytic system with water soluble nickel complex of S,S′-bis(2-pyridylmethyl)-1,2-thioethane over CdS nanorods for hydrogen evolution from water under visible light

In this paper, we report a new nickel complex, (bpte)NiCl₂] (bpte = S,S′-bis(2-pyridylmethyl)-1,2-thioethane) that can serve as a catalyst both for electrochemical and photochemical driven hydrogen production from water. As an electrocatalyst, (bpte)NiCl₂] can electrocatalyze hydrogen generation from a neutral buffer with a turnover frequency (TOF) of 555.78 mol of hydrogen per mole of catalyst per hour (mol H₂/mol catalyst/h) at an overpotential (OP) of 837.6 mV. Together with CdS nanorods (CdS NRs) as a photosensitizer, and ascorbic acid (H₂A) as a sacrificial electron donor, the nickel complex also can photocatalyze hydrogen evolution in heterogeneous environments and can work for 107 h. Under an optimal condition, the photocatalytic system can afford 24900 mol of H₂ per mole of catalyst during 83 h irradiation, with a TOF of 300H₂ per catalyst per hour. The average value of apparent quantum yield (AQY) is ～24% at 420 nm.