Metal-Free Triazine-Based Porous Organic Polymer-Derived N-Doped Porous Carbons as Effective Electrocatalysts for Oxygen Reduction Reaction

Abstract

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

Self-Sacrificial Templated Nanoarchitectonics of Nitrogen-Doped Carbon Derived from Viologen-Based Covalent Triazine Polymer: An Oxygen Reduction Electrocatalyst in Zinc–Air Batteries

“…The electrocatalytic activity of ACTP-2 was compared with the catalysts, similar to our work from the recent literature, and summarized in Table S1. Biswajit et al reported a metal-free triazine-based covalent−organic polymer-derived carbon which shows an onset potential of 0.83 V, with a half-wave potential of 0.728 V. 53 Yong et al reported an ultrasound-induced assembled covalent triazine polymer which showed good ORR activity with onset and a half-wave potential of 0.97 and 0.85 V, respectively. 54 Zhihu et al made an attempt to synthesize a metal-free covalent−organic framework with an onset potential of 0.89 V and half-wave potential of 0.74 V, 55 whereas Nana et al explored an isomeric covalent−organic framework with onset potential and limiting current density of 0.86 V and 5.4 mA/cm 2 , respectively.…”

“…The electrocatalytic activity of ACTP-2 was compared with the catalysts, similar to our work from the recent literature, and summarized in Table S1. Biswajit et al reported a metal-free triazine-based covalent–organic polymer-derived carbon which shows an onset potential of 0.83 V, with a half-wave potential of 0.728 V . Yong et al reported an ultrasound-induced assembled covalent triazine polymer which showed good ORR activity with onset and a half-wave potential of 0.97 and 0.85 V, respectively .…”

Molecular Design of Porous Organic Polymer-Derived Carbonaceous Electrocatalysts for Pinpointing Active Sites in Oxygen Reduction Reaction

“…During the subsequent one-step pyrosis process, abundant nitrogen content with a precise position, i.e., the regulated graphitic N and pyridine N, was successfully achieved ( Figure 4 b), demonstrating advanced ORR performance that was comparable to that of the commercial 20 wt% Pt/C catalyst. Nayak et al [ 29 ] synthesized N-doped carbon materials from triazine-based porous organic polymers (POPQs) by using 2,6-diaminoanthraquinone and cyanuric chloride as the building blocks. The derivative N/POPQ800 carbocatalyst with enriched N content, which was distributed uniformly throughout the framework, exhibited a low E onset = 0.832 Vvs.…”

Redox-Active Organic Materials: From Energy Storage to Redox Catalysis

“…Considering the utility of (immobilized) molecular redox mediators in electrocatalysis and of organic electrode materials for electrochemical energy storage, it is surprising that redox-active polymers remain understudied as heterogeneous electrocatalysts for organic synthesis (Figure ). This gap is particularly notable because redox-active organic materials have been widely studied as photoredox catalysts in organic synthesis − and as electrocatalysts in the context of clean energy and sustainability. − Herein, we outline the challenges and opportunities available for polymers as heterogeneous redox mediators relevant to organic synthesis, with an emphasis on amoprhous porous organic polymers (POPs) and crystalline covalent organic frameworks (COFs). − First, we present promising examples of photoredox catalysis with POPs and COFs, focusing on examples in which unique reactivity patterns can be achieved compared to molecular systems (section ). This discussion highlights the potential of polymeric organic materials to facilitate further redox transformations.…”