2D stacking of graphene and boron nitride for efficient metal free overall water splitting

Abstract

Constructing bifunctional electrocatalysts is essential for efficient water splitting. Rational interface engineering is an effective method for modifying active sites and promoting electronic charge transfer, resulting in improved water splitting efficiency. In this study, we designed a metal-free, 2D structure of graphene and boron nitride (h-BN). 2D stacking of two different layers generated abundant interfaces as well as huge electrochemical active sites. As a result, the graphene/h-BN stacked structure has a very low overpotential of 28 mV (for 10 mA/cm2 current density) for hydrogen evolution. At the same time, a significantly low overpotential of 360 mV (for 50 mA/cm2 current density) was achieved for oxygen evolution. The stacked structure of graphene/h-BN has been effectively utilized as a promising cathode and anode in a two-electrode system for accomplishing overall water splitting. Thus, our investigation suggests that rational construction of heterogeneous interfaces by stacking different 2D nanostructures can accelerate the overall water splitting by maximizing the electrochemical performance.