Graphene quantum dots piecing together into graphene on nano Au for overall water splitting

Abstract

Utilizing photocatalysts to split water into H2 and H2O2 simultaneously is an ideal but challenging process to obtain clean H2 energy and high valuable H2O2. Most of the photocatalysts currently studied for the overall water splitting are converting water into H2 and O2, resulting in further need of gas separation. Here, we reported a photocatalyst which can utilize the nano-Au based localized surface plasmonic resonance (LSPR) effect to produce H2 and H2O2 simultaneously. Nitrogen doped graphene quantum dots (N-GQDs) pieced together into large graphene through a catalytic process by chloroauric acid, in which dodecahedron nano-Au particles can also be obtained concurrently. Then Au wrapped up by graphene can be in situ formed with good interfaces. Photocatalytic activity tests revealed that the as prepared graphene@Au catalysts show efficient photocatalytic overall water splitting activity with a H2 evolution rate of 65.6 μmol g−1 h−1 and H2O2 generation rate of 49.7 μmol g−1 h−1. This work provides a feasible route for the facile fabrication of graphene through the bottom-up polycondensation of N-GQDs by amide bonds and new insights into the synthesis of photocatalysts for overall water splitting into H2 and H2O2.