Facile preparation of N-doped corncob-derived carbon nanofiber efficiently encapsulating Fe2O3 nanocrystals towards high ORR electrocatalytic activity

• 来源期刊: 能源化学
• 年，卷（期）: 2020,（5）
• 页码范围: 121-130
• 页数: 10页
• 语种: 英文

摘要

Facile preparation of cost-effective and durable porous carbon-supported non-precious-metal/nitrogen electrocatalysts for oxygen reduction reaction (ORR) is extremely important for promoting the commercialized applications of such catalysts.In this work,the FeCl3-containing porphyrinato iron-based covalent porous polymer (FeCl3.FePor-CPP) was fabricated in-situ onto porous corncob biomass supports via a simple one-pot method.Subsequent thermal-reduction pyrolysis at 700 ℃-900 ℃ with CO2 gas as an activating agent resulted in Fe2O3-decorated and N-doped graphitic carbon composite Fe2O3@NC&bio-C with a high degree of graphitization of Fe-involved promotion during pyrolysis (Fe2O3 =FeCl3.FePor-CPP derived Fe2O3;NC =N-doped graphene analog;bio-C =the corncob-derived hierarchically porous graphitic biomass carbon framework).The derived α-Fe2O3 and γ-Fe2O3 nanocrystals (5-10nm particle diameter)were all immobilized on the N-doped bio-C micro/nanofibers.Notably,the Fe2O3@NC&bio-C obtained at the pyrolysis temperature of 800 C (Fe2O3@NC&bio-C-g00),exhibited unusual ORR catalytic efficiency via a 4-electron pathway with the onset and half-wave potentials of 0.96V and 0.85V vs.RHE,respectively.In addition,Fe2O3@NC&bio-C-800 also exhibited a high and stable limiting current density of-6.0mAcm-2,remarkably stability (larger than 91％ retention after 10000s),and good methanol tolerance.The present work represents one of the best results for iron-based biomass material ORR catalysts reported to date.The high ORR activity is attributed to the uniformly distributed α-Fe2O3 and y-Fe2O3 nanoparticles on the N-enriched carbon matrix with a large specific surface area of 772.6m2 g-1.This facilitates favor faster electron movement and better adsorption of oxygen molecules on the surface of the catalyst.Nevertheless,comparative studies on the structure and ORR catalytic activity of Fe2O3@NC&bioC-800 with Fe2O3@bio-C-800 and NC&bio-C-800 clearly highlight the synergistic effect of the coexisting Fe2O3 nanocrystals,NC and bio-C on the ORR performance.