Metal-Free Triazine-Based\nPorous Organic Polymer-Derived\nN‑Doped Porous Carbons as Effective Electrocatalysts for Oxygen\nReduction Reaction

Abstract

In recent years, porous heteroatom-doped carbon materials\nhave\nbeen very promising for energy conversion. A newly designed porous\norganic polymer (POPQ) has been synthesized using two organic monomers, <i>i.e.</i>, 2,6-diaminoanthraquinone and cyanuric chloride, under\nreflux conditions for 72 h in an inert atmosphere. The triazine-containing\nporous organic polymers undergo pyrolysis, which produces two nitrogen-doped\nporous carbon materials, N/POPQ600 and N/POPQ800, at 600 and 800 °C\ntemperatures, respectively. Since the resultant N-doped porous materials\nhave a higher surface area than the parent porous organic polymer\nand the materials have a synergistic effect due to the enriched nitrogen\ncontent throughout the matrix, the metal-free N/POPQ600 and N/POPQ800\nmaterials exhibit good electrocatalytic activity toward oxygen reduction\nreaction (ORR). Among these, the N/POPQ800 material shows excellent\nORR activity with a nearly four-electron oxygen reduction pathway\nwhere the half-wave potential is estimated to be 0.728 V vs reversible\nhydrogen electrode (RHE), comparable with the commercially available\nPt/C catalyst. Most interestingly, the N/POPQ800 catalyst displays\noutstanding long-lasting stability. It shows a better methanol tolerance\ncapability than Pt/C, which can be attributed to the high specific\nsurface area and N-doped well-defined crystalline porous structure.\nAlso, the homogeneously distributed active sites throughout the carbon\nframework are the most precious for the electrochemical oxygen reduction\nreaction.