Polymer-Assisted Electrophoretic Synthesis of N-Doped Graphene-Polypyrrole Demonstrating Oxygen Reduction with Excellent Methanol Crossover Impact and Durability.
Chemistry
; 26(55): 12664-12673, 2020 Oct 01.
Article
em En
| MEDLINE
| ID: mdl-32614091
ABSTRACT
The design and synthesis of metal-free catalysts with superior electrocatalytic activity, high durability, low cost, and under mild conditions is extremely desirable but remains challenging. To address this problem, a polymer-assisted electrochemical exfoliation technique of graphite in the presence of an aqueous acidic medium is reported. This simple, cost-effective, and mass-scale production approach could open the possibility for the synthesis of high-quality nitrogen-doped graphene-polypyrrole (NG-PPy). The NG-PPy catalyst displays an improved half wave potential (E1/2 =0.77â
V) in alkaline medium compared with G-PPy (E1/2 =0.66â
V). Most importantly, this catalyst demonstrates excellent stability with high methanol tolerance, and it outperforms the commercial Pt/C catalyst and other previously reported metal-free catalysts. The content of graphitic nitrogen atoms is the key factor for the enhancement of electrocatalytic activity towards oxygen reduction reactions (ORR). Interestingly, the NG-PPy catalyst can be used as a cathode material in a zinc-air battery, which demonstrates a higher peak power density (59â
mW cm-2 ) than G-PPy (36.6â
mW cm-2 ), highlighting the importance of the low-cost material synthesis approach towards the development of metal-free efficient ORR catalysts for fuel cell and metal-air battery applications. Remarkably, the polymer-assisted electrophoretic exfoliation of graphite with a high yield (≈88â
wt %) of few-layer graphene flakes could pave the way towards the mass production of high-quality graphene for a variety of applications.
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2020
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Article