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Indexed by:期刊论文

Date of Publication:2017-02-28

Journal:APPLIED SURFACE SCIENCE

Included Journals:SCIE、EI

Volume:396

Page Number:986-993

ISSN No.:0169-4332

Key Words:Graphitization degree; N species; N-doped carbon; Oxygen reduction reaction; Chitosan

Abstract:It is of great interest to develop metal-free electrocatalysts derived from cheap and environmental friendly biomass for oxygen reduction reaction (ORR). Here we report a facile method to prepare graphene-like N-doped carbons with a high degree of graphitization and large surface area using chitosan as precursor and FeCl3 as soft template. The graphitization degree, surface area and the N species can be simply adjusted by controlling the annealing temperature. The soft template induced sample annealed at 800 degrees C (STS800) exhibits more positive onset potential than the samples annealed at 600 degrees C and 1000 degrees C (-0.08 V compared to -0.12 V and -0.15 V), which demonstrates that all of the high degree of graphitization, large surface area and the high percentages of pyridinic-N and graphitic-N play curial roles in the good ORR activity. The value of onset potential for STS800 is just 25 mV negative than that for Pt/C (-0.08 V to -0.055 V) and the ORR current density at merely -0.3 V for STS800 (-2.16 mA cm(-2)) is larger than that for Pt/C (-2.12 mA cm(-2)), which indicates its superior ORR activity even compared to Pt/C. Besides, the current for STS800 retains 95% at -0.2 V in 30000 s while that for Pt/C just retains 88%, which reveals its longer durability. With the addition of 3 M methanol, the CV curve of STS800 shows no noticeable current attenuation, indicating its good methanol tolerance. The excellent ORR activity, good methanol tolerance, and long durability demonstrate that STS800 could be a promising alternative for costly Pt-based electrocatalysts. (C) 2016 Elsevier B. V. All rights reserved.