Cobalt-embedded in ultrahigh boron and nitrogen codoped hierarchically porous carbon nanowires as excellent catalysts toward water splitting

The low heteroatoms doping amount and uncontrollable formation of electrochemically inactive boron (B)–nitrogen (N) bonds have hindered the electrocatalytic activities of B and N codoped carbonaceous catalysts. Herein, the novel three-dimensional (3D) cobalt (Co) nanoparticles (NPs)-embedded and ultrahigh B and N doped hierarchically porous carbon nanowires (denoted as [email protected]) have been successfully synthesized via pyrolyzing the 3D cobalt acetate/hydroxybenzeneboronic acid/polyvinylpyrrolidone precursor networks woven by electrospinning. After optimizing the pyrolysis temperatures, the optimal [email protected] owns a large surface area and abundant carbon edges/defects. Especially, 6.86 atom % of B and 6.59 atom % of N atoms are doped into carbon frameworks with affording 13.45 atom % of B/N active centers (i.e. BC3, pyridinic-N, Co-Nx-C, pyrrolic-N, and graphitic-N). In alkaline solution, the hydrogen evolution reaction overpotential at 10 mA cm−2 of the optimal [email protected] (151.3 mV) is just 82.4 mV larger than 20 wt% Pt/C (68.9 mV). Especially, the oxygen evolution reaction potential at 10 mA cm−2 of the optimal [email protected] (1.554 V vs. RHE) is even 2 mV more negative than RuO2 (1.556 V vs. RHE). For full water splitting, [email protected]s-800 based electrolysis cell just requires a small voltage of 1.596 V to achieve 10 mA cm−2, which is 19 mV smaller than that of the state-of-the-art 20 wt% Pt/C||RuO2 benchmark (1.615 V). The perfect 3D hierarchically porous structures and fairly abundant electrocatalytic active sites dispersed along [email protected]′s surface are responsible for the outstanding water splitting performances. In addition, as the good structural and chemical stabilities, [email protected] nanowires based water electrolysis cell also displays excellent water electrolysis stability.