Calcination of Porphyrin-Based Conjugated Microporous Polymers Nanotubes As Nanoporous N-Rich Metal-Free Electrocatalysts for Efficient Oxygen Reduction Reaction

Abstract

The development of non-noble metal electrocatalysts with high-performance and low cost are promising to replace expensive Pt or Pt-based alloy electrocatalysts for the oxygen reduction reaction (ORR). Herein, we demonstrate the fabrication of N-rich metal-free electrocatalysts based on hard carbon nanotubes derived from carbonization of nanotube-like porphyrin-based conjugated microporous polymers (denoted as TPP-CMP) for ORR. Taking advantage of their high specific surface, excellent porosity, and importantly, exposed N–C active site originating from the N-doping carbon nanotubes with unique hollow cylindrical geometry, the as-synthesized TPP-CMP exhibits excellent catalytic activity for ORR in alkaline medium. It shows a half-wave potential of 0.83 V, an onset potential of 0.95 V (vs RHE), a high diffusion limiting current density of 4.6 mA cm–2, which is comparable to the commercial Pt/C catalyst. More importantly, the TPP-CMP manifests higher methanol immunity and long-term stability than that of commercial Pt/C (20 wt %) catalyst for ORR in an alkaline medium. Furthermore, TPP-CMP exhibits a favorable a 4-electron reduction of oxygen (n ≈ 3.95) and lower H2O2 yield. These results make the TPP-CMP promising candidate as efficient electrocatalysts for ORR. In view of the designable flexibility and synthetic diversity of porous organic polymers (POPs), the findings obtained from this study may also open new possibilities for the future tailored design of POPs for creation of high-performance, metal-free ORR electrocatalyst only by a simple calcination process.

Pyrrole-Based Conjugated Microporous Polymers as Efficient Heterogeneous Catalysts for Knoevenagel Condensation

“…On account of the many functions and broad prospects of pyrrole-based materials, it is interesting to develop new kind of pyrrole-based architectures and explore their properties and applications. In this respect, even though several porphyrin-based CMPs have been reported ( Chen et al, 2010b ; Modak et al, 2013 ; Liu et al, 2014 ; Xu et al, 2019 ; Zhu et al, 2020 ), to the best of our knowledge, pyrrole-based CMPs are very rare ( Lee and Cooper, 2020 ).…”

N‐rich mesoporous carbon supported CoNC and FeNC catalysts derived from o‐phenylenediamine for oxygen reduction reaction

“…The result implied the presence of more defective sites in Co-OPD-800, which are conductive to current conduction. 44,49 It indicates that the Co-OPD catalyst has more oxygen reduction activity at the pyrolysis temperature of 800 C, which has a significant influence on its ORR performance.…”

“…The content of pyridine nitrogen is consistent with the subsequent electrochemical performance, which verifies the conjecture that the Lewis basic carbon atom connected to the pyridine nitrogen is the catalytically active site. 43,44,49 Moreover, to further explore the degree of graphitization and defects of the samples, the experiments are carried out the Raman analysis of three catalysts. The ID/IG ratios of Co-OPD-800, FeCl 3 -Co-OPD-800, and FeCl 3 -OPD-800 are 1.348, 1.369, and 1.42, respectively.…”

“…42 In our previous works, we have reported the fabrication of carbon-based ORR electrocatalysts using porous organic polymers (POPs) bearing with N-or Sheteroatoms as precursors through simple one-step carbonization. [43][44][45][46][47] Benefiting from their porous framework architecture and variable chemical composition, these POPs-based electrocatalysts show better ORR activity and stability. Inspired by these investigations, herein, we report the synthesis of CP based on poly(o-phenylenediamine) as a nitrogen-containing precursor for preparation of Co-and FeCl 3 -doped N-rich carbon for ORR (abbreviated as Co-OPD, FeCl 3 -OPD, and FeCl 3 -Co-OPD).…”

Ultrastable Conjugated Microporous Polymers Containing Benzobisthiadiazole and Pyrene Building Blocks for Energy Storage Applications

“…CMPs are porous compounds that are constructed from a covalent connection of π-conjugated building units that extended along with the skeleton, providing them 3D microporosity networks and especially high surface area at times [ 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. They can be easily synthesized by using numerous C–C coupling reactions such as Yamamoto, Sonogashira, and Suzuki coupling, and also oxidative polymerization [ 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 ] which are characterized by a high degree of polymerization and crosslinking densities, as well as facilities the incorporation of different moieties [ 45 , 46 , 47 , 48 , 49 , 50 ]. These coupling methods allow CMPs to highly possess CMPs to differentiate from other conventional polymers, with rapid ion/diffusion kinetics that originates from their individual porous properties [ 51 , 52 , 53 , 54 , 55 ].…”