Self-terminated activation for high-yield production of N,P-codoped nanoporous carbon as an efficient metal-free electrocatalyst for Zn-air battery

To enhance the electrocatalytic activity of heteroatom doped carbon for oxygen reduction reaction (ORR), high surface area and favorable porous structure are commonly required for providing sufficient accessible active sites. However, these features usually come with the severe carbon loss during pyrolysis and activation process. Herein, we report a facile self-terminated activation strategy for high-yield production of nitrogen and phosphorus codoped nanoporous carbon (NP-NC) by using potassium phytate as carbonaceous source. The in-situ formed potassium species enable the effective carbon activation to create plenty of nanopores without additional corrosive chemicals while the formation of K4P2O7 properly terminates the activation, resulting in the extremely low weight loss less than 17%. Benefited from the high surface area of 1294 m(2) g(-1) and trimodal nanoporous structure, the resulted N, P-codoped catalyst exhibits superior ORR activity close to Pt/C, high catalytic current density as well as excellent methanol tolerance and durability. Importantly, as cathode catalyst for Zn-air battery, N, P-NC also exhibits current and power densities comparable to the state-of-the art 20% Pt/C. Therefore, such a facile, scalable and high-yield synthesis of N, P-codoped nanoporous carbon materials opens up opportunities for the mass-production of highly efficient cost-effective electrocatalysts for energy applications. (C) 2017 Elsevier Ltd. All rights reserved.