Metal-free carbon semi-tubes for oxygen reduction electrocatalysis
Menghui Chen, Junxiang Chen, Chunguang Jia, Jin Luo, Zhili Yang, Joey Chung‐Yen Jung, Jiujun Zhang, Shengli Chen, Shiming Zhang
Abstract
New carbon morphologies are desirable in the development of high-performance carbon-based electrocatalysts for cathodic oxygen reduction reaction (ORR) of polymer electrolyte membrane fuel cells. In this work, a carbon semi-tube (CST) is successfully constructed by polymerizing m-phenylenediamine (mPDA) using surfactant-assembled micelles as a soft template. After pyrolysis, the CST morphology is retained in the formed N-doped CST (N-CST) catalyst. This mPDA-induced catalyst can provide rich micropores, high N-content, and good conductivity, imbuing it with superior catalytic ORR activity, stability, and methanol tolerance to the commercial Pt/C catalyst. By using such a metal-free N-CST as a cathode catalyst, an alkaline polymer electrolyte fuel cell exhibits a maximum power density of about 200 mW cm−2. Furthermore, density functional theory (DFT) calculations suggest that high curvature can be greatly conducive to the excellent catalytic ORR activity by the induced strong OOH∗ adsorption on active sites through a strong dipole-electric field interaction.