Hyper-Crosslinked Polymer-Derived Nitrogen-Doped Hierarchical Porous Carbon as Metal-Free Electrocatalysts for High-Efficiency Oxygen Reduction

Abstract

The development of N-doped porous carbon from porous organic polymers (POPs), especially low-cost hyper-crosslinked polymers (HCPs) provides an ideal platform for constructing carbon-based metal-free electrocatalysts with tunable chemical compositions and porous structures. However, most of the HCPs do not contain nitrogen, which makes it difficult to fabricate N-doped porous carbon by direct pyrolysis. Herein, a sort of N-doped hierarchically porous carbon using HCPs as a precursor is prepared by simple NH3 activation. The key factors affecting the catalytic performance of the obtained carbon catalysts can be regularly tuned by the pyrolysis temperature and building blocks, which results in an optimal catalyst (Py-NHCP-1000) with abundant nitrogen content, a high surface area (1865 m2 g–1), and rich defects. Remarkably, Py-NHCP-1000 with an outstanding electrocatalytic performance presents a positive shift of 27 mV for E1/2 relative to commercial Pt/C, and well durable and affordable qualities for the oxygen reduction reaction. Therefore, this work paves an avenue for designing and preparing a kind of affordable and high-efficiency metal-free electrocatalyst from low-cost and scalable HCPs and extending it to other energy storage/conversion materials.