塔菲尔方程
碳化
化学
共价键
氧气
材料科学
化学工程
纳米技术
电化学
物理化学
电极
有机化学
复合材料
扫描电子显微镜
工程类
作者
Sumin Wang,Zhiruo Shen,Qiguan Wang,Hongyan Wang
标识
DOI:10.1016/j.electacta.2021.139475
摘要
• An assembly motif of hydrogen-bonded organic frameworks is used to prepare a novel expanded and holey NCM (EH-NCM) with interlayer distance of 0.44 nm. • EH-NCM shows ORR activity with half wave potential of 0.93 V and H 2 O 2 yield of less than 4%, superior to the commercialized Pt/C. • The zinc-air battery (ZAB) based on EH-NCM shows a high capacity and excellent cycled stability, compared with Pt/C-based ZAB. • The theoretical calculation and potentiostatic intermittent titration technique (PITT) proved that the mass transfer is greatly improved in EH-NCM. We herein design a non-covalent assembly motif of hydrogen-bonded organic frameworks (HOF), which is experienced by a simple carbonization process to form a novel both expanded interlayer and holey in-plane nitrogen-containing nanocarbon material (EH-NCM). The escaped species in pyrolysis from the element decomposition in the HOF plays an important role in the simultaneous construction of holey defect and expanded interlayer. The potentiostatic intermittent titration experiment shows that oxygen diffusion coefficient in EH-NCM is improved by 1 order of magnitude compared with the commercial Pt/C and the unexpanded NCM. Calculations also show in-plane defects can efficiently bind with O 2 and benefit to four-electron oxygen reduction reaction (ORR) process, assisted by the enlarged interlayer distance. The as-prepared EH-NCM delivers ORR activity with half wave potential and onset potential at 0.93 V and 1.05 V respectively, limited current density of 6.1 mA cm −2 , and a low Tafel slope of 67 mV dec −1 , showing H 2 O 2 yield of less than 4% superior to the commercialized Pt/C. Also EH-NCM-based Zn–air battery displays excellent cathode performances. The accelerated mass transfer and maximum exposure of the active sites resulted from the holey and expanded dual structure of EH-NCM is responsible for the outstanding ORR performances. A non-covalent assembly motif of hydrogen-bonded organic frameworks is designed to simultaneously realize a novel both expanded and holey defective NCM (EH-NCM). Stimulated by the greatly boosted mass transfer, EH-NCM shows ORR activity with half wave potential of 0.93 V and H 2 O 2 yield of less than 4%, as well as a high capacity and excellent stability for zinc-air battery.
科研通智能强力驱动
Strongly Powered by AbleSci AI