Edge-selectively amidated graphene for boosting H2-evolution activity of TiO2 photocatalyst

To accelerate the H-2-evolution performance of graphene-modified photocatalytic materials, increasing effective interfacial active sites on graphene surface is greatly important. In this paper, ethylenediamine (EDA) as new and efficient interfacial H-2-evolution active sites was edge-selectively grafted on the reduced graphene oxide (rGO). Herein, the EDA-amidated graphene/TiO2 (TiO2/rGO-EDA) was successfully prepared by a facile acylation reaction via a selective reaction of amino groups in EDA with carboxylic groups on graphene edge. The highest H-2-evolution activity of TiO2/rGO-EDA reached 224.9 mu mol h(-1) g(-1), which was 3.96 and 1.53 times as high as that of TiO2 and TiO2/rGO, respectively. This can be attributed to the fact that the amino groups of amidated graphene act as active sites to efficiently adsorb H+ due to their strong nucleophilicity and then to accelerate the interfacial H-2-evolution reaction. Our paper demonstrates that the amino group is a promising H-2-evolution active site for developing new functionalized graphene-based photocatalysts.