Effective integration of hierarchically porous architecture and high-density distribution of dopant sites into carbon is essential to improve the activity of heteroatom-doped carbon for oxygen reduction reaction (ORR). Herein, we present a general sealed space-assisted approach to fabricate N, P-codoped porous carbon networks (NP-PCN) by calcination of a self-assembled mixture of C6H14N2O2, NH4H2PO4, and NaCl. The NaCl assemblies serve as a space-enclosed nanoreactor for the effective formation of hierarchical pores with high surface area and dense N, P-induced dopants by preventing the loss of N, Pcontaining gasses from the decomposition of precursors during annealing. The NP-PCN is applied as an ORR catalyst and exhibits excellent performance with a positive half-wave potential of 0.82 V vs. RHE, a low Tafel slope of 59 mV dec(-1), high tolerance to methanol, and high durability in alkaline media, making NP-PCN a promising alternative to costly platinum for the ORR. The enhanced performance is attributed to the combination of hierarchical pores and optimized N, P codoping, which significantly enhances the available number of catalytic sites by exposing the N, P-induced dopants and facilitates mass transfer in the ORR process. This finding opens a new avenue for the design of advanced porous carbons to improve their electrocatalytic activity. (C) 2017 Published by Elsevier Ltd.