Photocatalytic hydrogen evolution by two comparable [FeFe]-hydrogenase mimics assembled to the surface of ZnS.

Two photocatalytic hydrogen evolution systems were constructed by assembling [FeFe]-hydrogenase mimics, either carboxyl group-containing ( C1) or not ( C2), on to the surface of ZnS using triethanolamine as electron donor in DMF-H₂O (9/1, v/v) solution. Upon irradiation for 30 h, the turnover numbers of hydrogen evolution were 3400 and 4950 for the hybrid system C1/ZnS and C2/ZnS, respectively. The photocatalytic activity of the C2/ZnS system was five times higher than the activity of the pristine ZnS, suggesting that the [FeFe]-hydrogenase mimics are crucial toward improving the activity of ZnS. On the basis of the spectroscopic studies and analyses, the photogenerated electron transfer from ZnS to the mimics is probably responsible for the activity enhancement of ZnS. The time dependence of hydrogen generation shows that the mimic C2 is more active than C1. The different hydrogen evolution activity can be attributed to the different adsorption modes of the two [FeFe]-hydrogenase mimics on the surface of ZnS. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]