Abstract
Synthesis of metal-free carbon-based electrocatalysts for oxygen reduction reaction (ORR) to replace the conventional platinum-based catalysts has currently become a hot topic of research. This work proposes an activation-assisted carbonization strategy for the fabrication of nitrogen-doped nanoporous carbon microfibers (Me-CFZ-900) with a high BET surface area (~ 929.4 m2 g−1) via using melamine as a promoter/nitrogen source and bamboo-carbon biowastes as the carbon source with the help of a zinc chloride activator. Electrochemical tests showed that the Me-CFZ-900 material has exhibited excellent ORR electrocatalytic activity and long-term stability, and also displayed a quasi-four-electron ORR pathway in alkaline electrolyte. We also find that the graphitic-N may be the catalytically active site for the ORR, but the formation of planar-N can further help to promote the ORR activity for our catalysts. The results open a new space and provide a new idea to prepare valuable porous nanocarbon materials on the basis of carbonaceous solid wastes for catalysis of a wide range of electrochemical reactions in the future.
Highlights
Advanced electrochemical energy systems, such as fuel cells and metal-air batteries, are considered as promising alternatives for traditional fossil fuels [1, 2]
We find that the prepared Me-CFZ-900 catalyst has a large number of uniform mesopores with an average pore-diameter of 2.23 nm and a high surface area (~ 929.4 m2 g−1), which can be beneficial to the mass transportation of O2 electrocatalytic reduction
The formation of mesopores inside the Me-CFZ-900 catalyst is attributed to the role of zinc chloride activation during high-temperature pyrolysis that induces the rapid dehydration and catalytic dehydroxylation, resulting in the release of hydrogen and oxygen in the form of H2O vapor
Summary
Advanced electrochemical energy systems, such as fuel cells and metal-air batteries, are considered as promising alternatives for traditional fossil fuels [1, 2]. To look for some valuable substitutes for metal-Pt catalysts, the doping of heteroatoms into carbon allotropes such as graphene [8], graphdiyne [9], and carbon nanotube [10] is popularly studied owing to their distinctive physical and electronic structures. An immense improvement has been carried out on controlled-fabrication of the doped-carbon catalysts, the origin of ORR catalytic activity is still unclear, which becomes a technical bottleneck in this field [11, 12]. The enhancement of ORR activity of doped-carbon catalysts can be attributed to charge modulation and broken electroneutrality caused by the heteroatom doping in the carbon framework [13, 14].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
