A N, P Dual-Doped Carbon with High Porosity as an Advanced Metal-Free Oxygen Reduction Catalyst

摘要

Oxygen reduction reaction (ORR) is the critical reaction in metal-air batteries and fuel cells. This reaction suffers from sluggish kinetics and use of Pt-based catalysts that are prohibitively expensive and in shortage of resource. Therefore, an alternative advanced metal-free catalyst for ORR is highly desired. Herein, a N, P dual-doped porous carbon (NPPC) with large surface area is obtained through the CO2 activation of a novel N, P-doped aerogel (NPA). Ascribed to the CO2 activation of NPA, NPPC possesses a large Brunauer-Emmett-Teller specific surface area (2850 m(2) g(-1)) and N, P dual doping. CO2 activation as an environmentally friendly method with no corrosion can not only produce abundant micropores and mesopores in NPPC, but also provide a positive influence for the transformation of N species from pyrrolic N to pyridinic and graphitic N, which can promote the ORR activities. Therefore, compared with carbonized NPA, NPPC exhibits a higher ORR activity, including a larger transfer electron number (3.95 at 0.2 V vs reversible hydrogen electrode). Additionally, NPPC possesses a much better long-term stability compared with commercial 20 wt% Pt/C. This work gives an inspiration on the new strategy for preparing the future catalyst for ORR.