Engineering dual defective graphenes to synergistically improve electrocatalytic hydrogen evolution

Abstract

Herein, we have demonstrated the assembly of the N-doped defects and disordered structures into the typical sp2 carbon layers by nitrogen doping coupled to KOH etching at room temperature to achieve dual defective graphene-based materials (DDGMs) for excellent electrocatalytic hydrogen evolution reaction (HER). In our protocol, etching at high concentration KOH solution does result in lots of the disordered structures on the N-doped graphene materials (NGMs). Furthermore, the N-doped defects can be remained to a great extent after etching rather than completely remove them from carbon layers, which for the first time paves a feasible approach to disorder engineering toward NGMs to realize DDGMs. More importantly, such DDGMs exhibit significantly enhanced HER activity over the single defective graphene-based materials, including the N-doped or the etched N-undoped samples. Our data further reveal that the excellent HER activity comes from rich active sites of DDGMs. That is, the N-doped defects and disordered structures on DDGMs, might supply more active sites so as to synergistically enhance HER activity of the graphene-based electrocatalysts. This work opens up a novel approach to improving electrocatalytic activity of such metal-free catalysts, and promises the important applications in fields of electrocatalysis or energy conversion.