A highly efficient metal-free electrocatalyst of nitrogen-doped porous carbon nanoflowers toward oxygen electroreduction†

Metal-free catalysts offer a desirable alternative to traditional metal-based catalysts. However, it remains challenging to improve the catalytic performance of metal-free catalysts to be as promising as that of metal-based materials. Herein, a polymer-assisted method followed by pyrolysis treatment was employed to synthesize nitrogen (N)-doped porous carbon nanoflowers with nanosheet subunits. Leveraging the unique geometry structure and abundant pyridinic-N active sites, the optimized catalyst exhibits a good half-wave potential of 0.85 V versus reversible hydrogen electrode (vs. RHE) and long-term stability with only 17.0 mV negative shift of the half-wave potential after 10 000 cyclic voltammetry cycles in alkaline electrolyte. This research presents a viable strategy for advancing metal-free catalysts.