Secondary coordination sphere accelerates hole transfer for enhanced hydrogen photogeneration from [FeFe]-hydrogenase mimic and CdSe QDs in water

Achieving highly efficient hydrogen (H(2)) evolution via artificial photosynthesis is a great ambition pursued by scientists in recent decades because H(2) has high specific enthalpy of combustion and benign combustion product. [FeFe]-Hydrogenase ([FeFe]-H(2)ase) mimics have been demonstrated to be promising catalysts for H(2) photoproduction. However, the efficient photocatalytic H(2) generation system, consisting of PAA-g-Fe(2)S(2), CdSe QDs and H(2)A, suffered from low stability, probably due to the hole accumulation induced photooxidation of CdSe QDs and the subsequent crash of [FeFe]-H(2)ase mimics. In this work, we take advantage of supramolecular interaction for the first time to construct the secondary coordination sphere of electron donors (HA(−)) to CdSe QDs. The generated secondary coordination sphere helps realize much faster hole removal with a ~30-fold increase, thus leading to higher stability and activity for H(2) evolution. The unique photocatalytic H(2) evolution system features a great increase of turnover number to 83600, which is the highest one obtained so far for photocatalytic H(2) production by using [FeFe]-H(2)ase mimics as catalysts.