Biomass-derived graphene-like carbon nanoflakes for advanced supercapacitor and hydrogen evolution reaction

It is valuable that graphene-like carbon materials are prepared from the biomass resources due to their unique two-dimensional structure, heteroatom enriched, and high specific surface area. Herein, we use egg white and graphene oxides as precursor and employ post-hydrothermal carbonization approach, freeze-drying technique, carbonization, and activation methods by KOH to prepare the graphite carbon nanoflakes with Fe7C3 @graphite carbon nanoflakes hybrid materials. Morphology tests imply that the formation of graphite carbon nanoflakes are mainly depended by activation step, it implies that carbon flakes are exfoliated via introducing K+ into carbon layers and further destroying the van der Waals force (VDWF). As a result, this hybrid materials exhibit an attractive capacitance (528 mF·cm−2 @1 mA·cm−2) and durability (91 @10 mA·cm−2, 4000 cycles). For hydrogen evolution reaction (HER), the as-collected samples also deliver a low overpotential and remarkable stability. We believe that the as-obtained hybrid materials have a greatly application value in energy storage devices. •A high-quality of biomass-based graphene carbon nanosheets are developed.•N/O-GCN/Fe7C3@GCN displays the high specific surface area and abundant micropore.•N/O-GCN/Fe7C3@GCN demonstrates the promising specific area capacity and durability.•N/O-GCN/Fe7C3@GCN also deliver a low overpotential and superior stability.