Self-nitrogen-doped porous carbon prepared via pyrolysis of grass-blade without additive for oxygen reduction reaction

Biomass-derived N-doped carbon as oxygen reduction reaction (ORR) catalyst has captured great attention, for its low-cost, environment-friendly and high-activity. However, most preparations of biomass-derived N-doped carbon expend a lot of fossil nitrogen compounds and corrosivity chemical activators. Herein, this paper proposes a green strategy using spermacoce latifolia leaf as precursor without any additive by direct pyrolyzing to N-doped porous carbon. The as-synthesized spermacoce latifolia-derived carbon (SL-C-800) make a feature of high specific surface area (274.12 m2 g−1), abundant mesoporous, and rich doped nitrogen. The optimal SL-C-800 exhibits high four-electron ORR selectivity with high half-wave potential of 0.75 V, and long-term stability in alkaline medium, which is same to N-doped carbon nanotube. The experiments indicate that graphitic-N is the main active sites, while abundant mesoporous facilitates the O2 diffusion. Additionally, other porous carbons were synthesized by the same method, also exhibited excellent ORR performance. This work offers a new approach to design and synthesize carbon catalysts for ORR.