Silica-Templated Covalent Organic Framework-Derived Fe–N-Doped Mesoporous Carbon as Oxygen Reduction Electrocatalyst

The rational design and synthesis of mesoporous functional materials is of great significance to tackle fundamental challenges in materials science and to yield practical solutions for efficient energy utilization. Here, a novel p-toluenesulfonic acid-assisted mechanochemical approach is used to prepare a silica-templated bipyridine-containing covalent organic framework (COF), which can be further converted into an iron–nitrogen-doped mesoporous carbon (mC-TpBpy-Fe) upon carbonization and template removal. The resulting mC-TpBpy-Fe exhibits a large pore volume and surface area, which significantly promote the mass transfer efficiency and increase the accessibility of the active sites, yielding a high ORR activity with a competitive half-wave potential of 0.845 V and limiting current density of 5.92 mA/cm2 (vs 0.852 V and 5.57 mA/cm2 for Pt/C). Application of this COF derived mesoporous carbon within a Zn–air battery revealed that it can operate in ambient conditions with a competitive discharge performance, showing its potential for practical applications.