TY - JOUR
T1 - Towards electrochemical purification of chemically reduced graphene oxide from redox accessible impurities
AU - Tan, Shu Min
AU - Ambrosi, Adriano
AU - Khezri, Bahareh
AU - Webster, Richard D.
AU - Pumera, Martin
PY - 2014/4/21
Y1 - 2014/4/21
N2 - The electrochemical properties of graphene are highly sensitive to residual metallic impurities that persist despite various purification efforts. To accurately evaluate the electrochemical performance of graphene, highly purified materials free of metallic impurities are required. In this study, the partial purification of chemically reduced graphene oxides prepared via Hummers (CRGO-HU) and Staudenmaier (CRGO-ST) oxidation methods was performed through cyclic voltammetric (CV) scans executed in nitric acid, followed by CV measurements of cumene hydroperoxide (CHP). The purification of graphene was monitored by the changes in the peak current and potential of CHP which is sensitive to iron impurities. The CRGOs were characterised by inductively coupled plasma-mass spectrometry (ICP-MS), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and CV. The micrographs revealed CRGOs of similar morphologies, but with greater defects in CRGO-HU. The dependencies of CHP peak current and peak potential on the number of purification cycles exhibit greater efficiency of removing iron impurities from CRGO-HU than CRGO-ST. This can be attributed to the oxidative method that is used in CRGO-HU production, which exposes more defect sites for iron impurities to reside in. This facile electrochemical purification of graphenes can be utilised as a routine preparation and cleaning method of graphene before electrochemical measurements for analytes that show exceptional sensitivity towards electrocatalytic metallic impurities in sp 2 nanocarbon materials.
AB - The electrochemical properties of graphene are highly sensitive to residual metallic impurities that persist despite various purification efforts. To accurately evaluate the electrochemical performance of graphene, highly purified materials free of metallic impurities are required. In this study, the partial purification of chemically reduced graphene oxides prepared via Hummers (CRGO-HU) and Staudenmaier (CRGO-ST) oxidation methods was performed through cyclic voltammetric (CV) scans executed in nitric acid, followed by CV measurements of cumene hydroperoxide (CHP). The purification of graphene was monitored by the changes in the peak current and potential of CHP which is sensitive to iron impurities. The CRGOs were characterised by inductively coupled plasma-mass spectrometry (ICP-MS), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and CV. The micrographs revealed CRGOs of similar morphologies, but with greater defects in CRGO-HU. The dependencies of CHP peak current and peak potential on the number of purification cycles exhibit greater efficiency of removing iron impurities from CRGO-HU than CRGO-ST. This can be attributed to the oxidative method that is used in CRGO-HU production, which exposes more defect sites for iron impurities to reside in. This facile electrochemical purification of graphenes can be utilised as a routine preparation and cleaning method of graphene before electrochemical measurements for analytes that show exceptional sensitivity towards electrocatalytic metallic impurities in sp 2 nanocarbon materials.
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U2 - 10.1039/c4cp00371c
DO - 10.1039/c4cp00371c
M3 - Article
AN - SCOPUS:84897853444
SN - 1463-9076
VL - 16
SP - 7058
EP - 7065
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
IS - 15
ER -