Hydrogel-derived heteroatom-doped porous carbon networks for supercapacitor and electrocatalytic oxygen reduction

Novel boron and nitrogen co-doped hierarchically porous carbon networks were prepared through a green, simple, and innovative template-free pyrolysis of agarose hydrogel containing TBE buffer (Tris base, boric acid and ethylenediaminetetraacetic acid) followed by chemical activation (KOH). The resulting materials with 3D interconnected hierarchically pore structure, high specific surface area of 2666 m² g^-1 and moderate heteroatoms contents exhibit a high specific capacitance of 214 F g^-1 at 0.2 A g^-1 in 6 M KOH electrolyte and excellent electrocatalytic oxygen reduction activity comparable to and methanol tolerance better than those of commercial 20 wt% Pt/C catalysts in O₂-saturated 0.1 M KOH solution.