Single-step Synthesis of Highly Porous Nitrogen-doped Carbon by Solid–gas Mechanochemical Treatment as an Oxygen Reduction Electrocatalyst (Supporting Information)

Herein, we report a single-step mechanochemical synthesis of highly porous nitrogen-doped carbon and its electrocatalytic oxygen reduction activity. X-ray diffraction and X-ray photoelectron spectroscopy measurements revealed that solid–gas mechanochemical treatment (MT) using a planetary ball mill cleaved the C–C bonds in carbon black (CB) and simultaneously incorporated nitrogen atoms with a high proportion of quaternary N into the carbon network. MT at a milling speed of 600 rpm yielded nitrogen-doped porous carbon (N-PC) with an optimal combination of nitrogen content of 2.20 at% and surface area of 516 m2 g−1, which is 10 times larger than that of CB (51.1 m2 g−1). Owing to the high nitrogen content and large surface area, N-PC synthesized by MT at a milling speed of 600 rpm exhibited higher oxygen reduction activity than N-PC synthesized by MT at a milling speed of 800 rpm and porous carbon synthesized by MT at a milling speed of 300 rpm.

本文报道了一种一步法机械化学合成高孔隙氮掺杂碳的方法，并考察了其电催化氧还原活性。通过X射线衍射（X-ray diffraction, XRD）与X射线光电子能谱（X-ray photoelectron spectroscopy, XPS）表征可知，采用行星式球磨机开展的固-气机械化学处理（solid–gas mechanochemical treatment, MT）可断裂炭黑（carbon black, CB）中的碳碳键，并将高占比的季氮（quaternary N）原子引入碳骨架网络中。当球磨转速为600 rpm时，所制备的氮掺杂多孔碳（nitrogen-doped porous carbon, N-PC）的氮含量为2.20 at%，比表面积达516 m²·g⁻¹，该性能组合为最优；其比表面积是原始炭黑（51.1 m²·g⁻¹）的10倍。得益于较高的氮含量与较大的比表面积，600 rpm转速下制备的N-PC，其氧还原活性优于800 rpm转速下制备的N-PC，以及300 rpm转速下经MT制备的纯多孔碳。