The synergetic effect of hydrophilic and hydrophobic carbon can be used to obtain tunable hydrogen evolution reaction (HER) at the interface. Herein, graphene oxide (GO-Hummers method) was coated on graphene foam (GF) synthesized via chemical vapor deposition to develop mixed-dimensional heterostructure for the observation of HER. The porosity of GF not only provides an optimized diffusion coefficient for better mass transport but also modified surface chemistry (GF/GO-hydrophobic/hydrophilic interface), which results in an onset potential 50 mV and overpotential of 450 mV to achieve the current density 10 mA/cm2. The surface analysis shows that inherent functional groups at the surface played a key role in tuning the activity of hybrid, providing a pathway to introduce non-corrosive electrodes for water splitting.
