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Enzymatic in situ synthesis of graphene oxide/polypyrrole composites by peroxidase and their electrical capacitance
Author(s) -
Xu Yue,
Raseda Nasrin,
Yoo Ikkeun,
Ryu Keungarp
Publication year - 2019
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.23244
Subject(s) - polypyrrole , graphene , materials science , supercapacitor , oxide , tetrafluoroborate , aqueous solution , composite material , ionic liquid , capacitance , graphite oxide , electrolyte , cyclic voltammetry , chemical engineering , electrochemistry , electrode , polymer , nanotechnology , chemistry , polymerization , organic chemistry , catalysis , engineering , metallurgy
Recently, diverse composites between carbon nanomaterials and conducting polymers have been intensively investigated for a variety of applications such as sensors and supercapacitors. These composites have been synthesized by either chemical or electrochemical methods, which have the drawbacks of using toxic oxidants or requiring complicated apparatus, respectively. The present study reports that the graphene oxide/polypyrrole (GO/PPy) composites can be easily synthesized in a single‐step catalyzed by horseradish peroxidase in an aqueous solution (pH 4.0). Scanning electron microscopy of the enzymatically synthesized GO/PPy composites shows that GO sheets are evenly coated with PPy without observable granular PPy particles. A symmetric two‐electrode coin cell capacitor (20 mm in diameter and 1.6 mm in thickness) was made to measure the electrical capacitance in an aqueous electrolyte (1 mol/L NaNO 3 ) by the galvanostatic charge/discharge method. When the discharge current was 0.5 mA, the specific capacitance of the GO/PPy composites (46.6 F/g) was ∼390 times greater than graphene oxide (0.12 F/g) or ∼7 times greater than polypyrrole (6.7 F/g). Furthermore, the addition of a 0.2 L/L (20 vol%) water‐miscible ionic liquid, 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([BMIM][BF 4 ]), into the aqueous electrolyte enhanced the capacitance of the GO/PPy composites by 57 % at maximum.