ArticlePDF Available

Degradation of Graphene by Hydrogen Peroxide

  • Millennial Scientific

Abstract and Figures

Graphene, the 2D carbon nanomaterial, is suitable for diverse applications, ranging from electronics and telecommunication, to energy and healthcare. Despite its tremendous technological and commercial prospects, its interactions with biological and environmental constituents still require thorough examination. Here, we report that pristine multilayered graphene degrades in the presence of the naturally occurring, ubiquitous compound hydrogen peroxide (H 2 O 2 ) at physiologically and environmentally relevant concentrations (1–10 000 × 10 −6 M ) at various time points (0–25 h).
Content may be subject to copyright.
© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 745
and >1 × 10
3 M cause necrosis.
[ 22 ] Thus, given the widespread
presence of H
2 O 2 in the body and environment, and the future
impact graphene may have on human health and environment,
systematic studies need to be performed to investigate the direct
chemical interaction between H
2 O 2 and graphene. As a fi rst
step, in this communication, we examine the effects of H
2 O 2
on multilayered pristine graphene at physiologically and envi-
ronmentally relevant concentrations (1–10 000 × 10
6 M ). [ 19,22,23 ]
Pristine multilayered graphene deposited on nickel wafer
(wafer size = 1 cm × 1 cm, Graphene Supermarket, Calverton,
NY, USA) or directly onto TEM grids was placed in petri dishes
and treated with H
2 O 2 solution at concentrations of 1 × 10
6 ,
100 × 10
6 , or 10 000 × 10
6 M ( n = 4 per group). Graphene incu-
bated with distilled water (DI) served as the control. As H
2 O 2
solutions gradually deteriorate,
[ 22 ] the solutions were aspirated
out every hour and exchanged with fresh solutions. The experi-
ments were terminated after 10 or 25 h. At these time points,
solutions were completely removed, and graphene substrates
were air-dried. Graphene samples before (time t = 0 h) and after
2 O 2 treatment (time t = 10 and 25 h) were examined with
transmission electron microscopy (TEM), atomic force micros-
copy (AFM), and confocal Raman spectroscopy (laser excitation
of 532 nm).
Figure 1 shows representative TEM images of graphene-
coated TEM grids incubated with various concentrations of
2 O 2 for 10 h. Figure 1 A shows the control graphene sheet
incubated with DI water with no holes or defects, and has
the basic hexagonal lattice of graphene, possessing 0.142 nm
carbon–carbon bond length, occupying 0.17 nm
2 area. [ 24 ]
Compared with the control group (Figure 1 A), graphene
with 1 × 10
6 M H 2 O 2 treatment after 5 h showed the pres-
ence of randomly distributed small holes as seen in Figure 1 B
(arrows point to few representative holes). The diameter dis-
tribution of holes on graphene was measured by analyzing
multiple ( n = 20) TEM images. Incubation of graphene with
1 × 10
6 M H 2 O 2 for 10 h resulted in the formation of holes
ranging from 1 to 15 nm diameter (representing an area
up to 175 nm
2 ). Thus, these visible holes indicate a “cluster
effect,” i.e., the holes, or defect sites are generated initially by
random attack of H
2 O 2 followed by progressive attraction of
more H
2 O 2 to destroy carbon–carbon bonds around the ini-
tial defect sites. This effect is dependent on the concentration
of H
2 O 2 , and enhanced by higher concentrations of H
2 O 2 .
Upon treatment with 100 × 10
6 M H 2 O 2 , formation of larger-
sized holes (10–15 nm) was observed (Figure 1 C). Addition-
ally, Figure 1 C also shows formation of lighter (few graphene
layers) and darker regions (multiple graphene layers) indi-
cating the degradation of multilayered graphene. Figure 1 D
shows graphene after incubation with 10 000 × 10
6 M H 2 O 2 .
Large-defect sites (10–30 nm) and few graphene layers were
observed corresponding to the degradation of majority of the
graphene sheets.
W. Xing, G. Lalwani, Prof. B. Sitharaman
Department of Biomedical Engineering
Stony Brook University
Stony Brook , New York 11794–5281, USA
Dr. I. Rusakova
Texas Center for Superconductivity
and Advanced Materials
University of Houston Science Center
Houston, Texas 77004–5002 , USA
DOI: 10.1002/ppsc.201300318
Degradation of Graphene by Hydrogen Peroxide
WeiLiang Xing , Gaurav Lalwani , Irene Rusakova , and Balaji Sitharaman *
Graphene, the 2D carbon nanomaterial, is suitable for diverse
applications, ranging from electronics and telecommunication,
to energy and healthcare. Despite its tremendous technological
and commercial prospects, its interactions with biological and
environmental constituents still require thorough examination.
Here, we report that pristine multilayered graphene degrades in
the presence of the naturally occurring, ubiquitous compound
hydrogen peroxide (H
2 O 2 ) at physiologically and environmen-
tally relevant concentrations (1–10 000 × 10
6 M ) at various time
points (0–25 h).
Graphene, a 2D sheet comprised of sp
2 -hybridized carbon
possessing exciting electrical, mechanical, thermal, and optical
[ 1 ] has been investigated as enabling components in
fuel cells,
[ 2,3 ] sensors, [ 2,4 ] photocatalysis, [ 5 ] electronics, [ 6 ] compos-
[ 7 ] electrical and optical biosensors,
[ 8 ] drug delivery,
[ 9 ] tissue
[ 10,11 ] and imaging probes.
[ 12 ] Recent reports predict
that graphene may overtake carbon nanotubes in commercial
[ 13 ] The development of potential graphene-based
commercial technologies for applications in material and bio-
medical sciences has raised concerns about its short-term and
long-term effects on human health and the environment,
[ 14 ]
and leads to multiple investigations to assess and evaluate these
[ 15 ]
An important attribute to be examined while investigating
graphene's effect on human health and environment is its
bio- and environmental-degradation properties. Several studies
have investigated the biodegradation of carbon nanotubes,
[ 16,17 ]
wherein enzymes such as horseradish peroxidase (HRP) and
human myeloperoxidase (hMPO) were employed to catalyze
oxidative degradation of these nanomaterials. A recent study
has used a similar strategy on graphene oxide, and exploits the
catalytic activity of HRP enzyme.
[ 18 ] H 2 O 2 is a component of
this degradation process.
H 2 O 2 is a naturally occurring, ubiquitous compound and a
strong oxidizing agent, found in rain and surface water, and
[ 19,20 ] Its concentration in natural water sources has been
determined to be 1–7 × 10
3 M . [ 19,21 ] In normal living cells,
diverse cellular pathways synthesize H
2 O 2 in tightly regulated
concentrations varying between 1 × 10
9 and 700 × 10
9 M . H 2 O 2
steady-state concentrations >1 × 10
6 M cause oxidative stress,
Part. Part. Syst. Charact. 2014, 31, 745–750
© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
AFM was performed (using a previously described proce-
[ 11 ] to assess the surface topography of graphene sheets
before and after H
2 O 2 treatment. Samples were incubated
with DI water and 10 000 × 10
6 M H 2 O 2 for 25 h. Pristine
graphene sheets ( Figure 2 A,C,E) appeared smooth, without
any topographical defects. Randomly distributed holes in
graphene sheets were observed after incubation with H
2 O 2
(Figure 2 B,D,E). The diameter of holes ranged from 5.3 to
13.5 nm. Compared with the height of single graphene sheet
(0.34 nm),
[ 18 ] the depth of the holes (9.4–13.5 nm, inset
Figure 2 D) was greater by several folds suggesting the attack of
2 O 2 on the inner layers of graphene. Once superfi cial defect
sites are generated, H
2 O 2 may pass through these defect sites
attacking the underlying C–C bonds, and accelerating the deg-
radation of graphene at higher concentrations of H
2 O 2 .
Raman spectroscopy was used to characterize the graphene
samples before and after treatment with H
2 O 2 at every time
point ( Figure 3 ). The ratio of D-band and G-band intensities
( I D / I G ) at all-time points before and after H
2 O 2 treatment are tab-
ulated in Table 1 . The D band indicating the degree of disorder
in sp
2 -hydridized carbon system was observed between 1335 and
1350 cm
1 , and the G band, indicating stretching of graphitic
carbon, was observed between 1570 and 1580 cm
1 . [ 25 ] Table 1
shows decrease in the intensity of D and G bands for all groups
treated with various concentration of H
2 O 2 for 25 h, suggesting
a gradual structural degradation of graphene.
[ 26 ] For groups
treated with 1 × 10
6 and 100 × 10
6 M H 2 O 2 , the I D / I G ratio
increased within 10 h of incubation, and decreased at later time
points. Increase in I D / I G ratio during initial time points can be
attributed to increase in the number of defects on graphene, and
is consistent with previous reports on enzymatic degradation of
[ 17,18,26 ] The decrease in I D / I G ratio at later time points
can be attributed to disintegration of the multiple layers of gra-
phene due to progressive increase in the defect sizes, exposing
the underlying pristine graphene layers.
[ 26 ] The Raman spectra
from these underlying pristine graphene layers would have an
intense G band, reducing the I D / I G ratio. For the group treated
with 10 000 × 10
6 M H 2 O 2 , I D / I G ratio progressively decreased
at all time points, unlike 1 × 10
6 and 100 × 10
6 M H 2 O 2 treat-
ment groups, which showed an initial increase in the I D / I G ratio
within the fi rst 10 h. After 25 h, both D and G bands almost dis-
appeared for the 10 000 × 10
6 M H 2 O 2 treatment group.
G band, a characteristic of layered graphene, was observed
at 2750 cm
1 for all treatment groups.
[ 27 ] The intensity of
G band increased during the fi rst 10 h of H
2 O 2 treatment,
decreased, and became negligible at later time points. The
G band became progressively narrow and down shifted at
increasing time points. Several reports have shown the rela-
tion of G band with the number of layers of graphene in which
wider, higher intensity, and an upshift of G band corresponds
to increasing number of graphene layers.
[ 25,27,28 ] In this study,
as the degradation progressed, decrease in the width, intensity,
and downshift of G band corresponds to progressive, layer-
by-layer degradation of graphene. A layer-by-layer degradation
phenomenon was observed during degradation of multiwalled
carbon nanotubes by HRP.
[ 17,29 ] Furthermore, differences in G
band peak intensity and width between various H
2 O 2 treatment
groups imply the dependence of graphene degradation rate on
Figure 1. Representative TEM images of multilayered graphene treated with A) deionized water, B) 1 × 10
6 M H 2 O 2 , C) 100 × 10
6 M H 2 O 2 , and
D) 10 000 × 10
6 M H 2 O 2 for 10 h. Arrows in (B) indicate the formation of holes on graphene sheets, and arrows in (C) indicate the formation of lighter
(few graphene layers) and darker regions (multiple graphene layers) suggesting the degradation of multilayered graphene. It should be noted that the
arrows in (B–D) only point to a few representative holes.
Part. Part. Syst. Charact. 2014, 31, 745–750
© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 747
the concentration of hydrogen peroxide, i.e., graphene treated
with 1 × 10
6 M H 2 O 2 may degrade at a slower rate compared to
treatment with 10 000 × 10
6 M H 2 O 2 .
The above results taken together clearly indicate the deg-
radation of multilayered pristine graphene at a wide range of
2 O 2 concentrations found in living systems and environment.
Previous studies report that metal ions such as nickel (Ni), iron
(Fe), and copper (Cu) can catalyze the degradation of H
2 O 2 to
form reactive hydroxyl radicals via the Haber–Weiss reaction.
[ 30 ]
Ni, Fe, or Cu-based substrates or catalysts are used for graphene
Figure 2. Representative AFM images of multilayered graphene on Ni wafer. A,C,E) are topographical scans of pristine graphene samples (incubated
with DI water) and B,D,E) are graphene after 25 h of H
2 O 2 treatment (10 000 × 10
6 M). Insets in images C and D correspond to the line height profi le.
Images E and F are 3D representations of images C and D, respectively.
Part. Part. Syst. Charact. 2014, 31, 745–750
© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
synthesis using the chemical vapor deposition method.
[ 31 ] Thus,
in this study, the presence of trace amounts of Ni used during
the CVD synthesis of the graphene may be catalyzing the deg-
radation of graphene during H
2 O 2 treatment. The results also
indicate that rate of degradation of graphene is dependent
on H
2 O 2 exposure concentration; increase in concentration
accelerates graphene’s degradation. The visible holes indicate a
“cluster effect,” i.e., the holes, or defect sites are generated ini-
tially by random attack of H
2 O 2 followed by progressive attrac-
tion of more H
2 O 2 to destroy the carbon–carbon bond around
initial defect sites. Furthermore, reaction temperature may also
infl uence the degradation rate. Additional studies are necessary
Figure 3. Representative Raman spectra of graphene treated with A) 10 000 × 10
6 M H 2 O 2 , B) 100 × 10
6 M H 2 O 2 , and C) 1 × 10
6 M H 2 O 2 for a period
of 0, 10, and 25 h. Decrease in the D and G band intensities can be observed after 25 h. Figures D–F show the corresponding I D / I G intensity ratio at
every time point .
Part. Part. Syst. Charact. 2014, 31, 745–750
© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 749
Table 1. I D / I G ratio of multilayered graphene samples before and after
incubation with H
2 O 2 for 25 h.
2 O 2 incubation
I D / I G
Before incubation After incubation (25 h)
10 000 × 10
6 M 0.2312 0.1706
100 × 10
6 M 0.2312 0.1519
1 × 10
6 M 0.2312 0.1499
Received: September 25, 2013
Revised: December 12, 2013
Published online: February 24, 2014
[1] a) S. Latil , L. Henrard , Phys. Rev. Lett. 2006 , 97 , 036803 ;
b) K. S. Novoselov , A. K. Geim , S. V. Morozov , D. Jiang , Y. Zhang ,
S. V. Dubonos , I. V. Grigorieva , A. A. Firsov , Science 2004 , 306 ,
666 ; c) R. F. Service , Science 2009 , 324 , 875 ; d) A. A. Balandin ,
S. Ghosh , W. Bao , I. Calizo , D. Teweldebrhan , F. Miao , C. N. Lau ,
Nano Lett. 2008 , 8 , 902 ; e) Q. Bao , H. Zhang , Y. Wang , Z. Ni , Y. Yan ,
Z. X. Shen , K. P. Loh , D. Y. Tang , Adv. Funct. Mater. 2009 , 19 , 3077 ;
f) Q. Bao , K. P. Loh , ACS Nano 2012 , 6 , 3677 .
[2] D. R. Kauffman , A. Star , Analyst 2010 , 135 , 2790 .
[3] C. Liu , S. Alwarappan , Z. Chen , X. Kong , C. Z. Li , Biosens. Bioelec-
tron. 2010 , 25 , 1829 .
[4] C. H. Lu , H. H. Yang , C. L. Zhu , X. Chen , G. N. Chen , Angew. Chem
Int. Ed. Engl. 2009 , 48 , 4785 .
[5] a) N. Zhang , Y. Zhang , Y. J. Xu , Nanoscale 2012 , 4 , 5792 ;
b) Y. Zhang , Z. R. Tang , X. Fu , Y. J. Xu , ACS Nano 2010 , 4 , 7303 ;
c) Y. Zhang , N. Zhang , Z. R. Tang , Y. J. Xu , ACS Nano 2012 , 6 , 9777 ;
d) J. G. Radich , P. V. Kamat , ACS Nano 2013 , 7 , 5546 .
[6] a) M. Freitag , Nat. Nanotechnol. 2008 , 3 , 455 ; b) R. M. Westervelt ,
Science 2008 , 320 , 324 .
[7] a) H. Bai , C. Li , X. Wang , G. Shi , Chem. Commun. 2010 , 46 , 2376 ;
b) L. Ren , X. Qi , Y. Liu , Z. Huang , X. Wei , J. Li , L. Yang , J. Zhong , J.
Mater. Chem. 2012 , 22 , 11765 .
[8] a) H. Jang , Y. K. Kim , H. M. Kwon , W. S. Yeo , D. E. Kim , D. H. Min ,
Angew. Chem Int. Ed. Engl. 2010 , 49 , 5703 ; b) M. Zhou , Y. Zhai ,
S. Dong , Anal. Chem. 2009 , 81 , 5603 .
[9] a) X. Sun , Z. Liu , K. Welsher , J. T. Robinson , A. Goodwin , S. Zaric ,
H. Dai , Nano Res. 2008 , 1 , 203 ; b) S. M. Chowdhury , G. Lalwani ,
K. Zhang , J. Y. Yang , K. Neville , B. Sitharaman , Biomaterials 2013 ,
34 , 283 .
[10] a) T. R. Nayak , H. Andersen , V. S. Makam , C. Khaw , S. Bae , X. Xu ,
P. L. Ee , J. H. Ahn , B. H. Hong , G. Pastorin , B. Ozyilmaz , ACS
Nano 2011 , 5 , 4670 ; b) G. Lalwani , A. T. Kwaczala , S. Kanakia ,
S. C. Patel , S. Judex , B. Sitharaman , Carbon N Y 2013 , 53 , 90 .
[11] G. Lalwani , A. M. Henslee , B. Farshid , L. Lin , F. K. Kasper ,
Y. X. Qin , A. G. Mikos , B. Sitharaman , Biomacromolecules 2013 , 14 ,
900 .
[12] a) S. Zhu , J. Zhang , C. Qiao , S. Tang , Y. Li , W. Yuan , B. Li , L. Tian ,
F. Liu , R. Hu , H. Gao , H. Wei , H. Zhang , H. Sun , B. Yang , Chem.
Commun. 2011 , 47 , 6858 ; b) B. S. Paratala , B. D. Jacobson ,
S. Kanakia , L. D. Francis , B. Sitharaman , PLoS One 2012 , 7 , e38185 ;
c) G. Lalwani , X. Cai , L. Nie , L. V. Wang , B. Sitharaman , Photoacous-
tics 2013 , 1 , 62 ; d) S. Kanakia , J. D. Toussaint , S. M. Chowdhury ,
G. Lalwani , T. Tembulkar , T. Button , K. R. Shroyer , W. Moore ,
B. Sitharaman , Int. J. Nanomed. 2013 , 8 , 2821 .
[13] M. Segal , Nat. Nanotechnol. 2009 , 4 , 612 ; Nat. Nanotechnol. 2008 ,
3 , 523 .
[14] A. D. Maynard , R. J. Aitken , T. Butz , V. Colvin , K. Donaldson ,
G. Oberdorster , M. A. Philbert , J. Ryan , A. Seaton , V. Stone ,
S. S. Tinkle , L. Tran , N. J. Walker , D. B. Warheit , Nature 2006 , 444 , 267 .
[15] a) S. Zhang , K. Yang , L. Feng , Z. Liu , Carbon 2011 , 49 , 4040 ;
b) Y. Zhang , S. F. Ali , E. Dervishi , Y. Xu , Z. Li , D. Casciano ,
A. S. Biris , ACS Nano 2010 , 4 , 3181 ; c) S. R. Ryoo , Y. K. Kim ,
M. H. Kim , D. H. Min , ACS Nano 2010 , 4 , 6587 ; d) B. Parvin , I. Refi ,
F. Bunshi , Carbon 2011 , 49 , 3907 ; e) T. S. Sreeprasad , T. Pradeep ,
Int. J. Mod. Phys. B 2012 , 26 , 1242001 .
[16] a) B. L. Allen , G. P. Kotchey , Y. Chen , N. V. K. Yanamala ,
J. Klein-Seetharaman , V. E. Kagan , A. Star , J. Am. Chem. Soc. 2009 ,
131 , 17194 ; b) B. L. Allen , P. D. Kichambare , P. Gou , I. I. Vlasova ,
A. A. Kapralov , N. Konduru , V. E. Kagan , A. Star , Nano Lett. 2008 , 8 ,
3899 ; c) V. E. Kagan , N. V. Konduru , W. Feng , B. L. Allen , J. Conroy ,
Y. Volkov , I. I. Vlasova , N. A. Belikova , N. Yanamala , A. Kapralov ,
Y. Y. Tyurina , J. Shi , E. R. Kisin , A. R. Murray , J. Franks , D. Stolz ,
P. Gou , J. Klein-Seetharaman , B. Fadeel , A. Star , A. A. Shvedova ,
Nat. Nanotechnol. 2010 , 5 , 354 .
[17] Y. Zhao , B. L. Allen , A. Star , J. Phys. Chem. A 2011 , 115 , 9536 .
and currently underway to test the above hypothesis and pro-
vide better understanding of chemical mechanism of H
2 O 2 -
mediated degradation of graphene (interplay of H
2 O 2 concen-
tration, reaction temperature, and presence of metal ions).
A wide variety of catalytic peroxidase enzymes such as MPO,
HRP, and lignin peroxidase (LiP) are present in the body or
environment. Several studies have investigated the effects of
enzymes such as HRP and hMPO on the degradation of single-
and multiwalled carbon nanotubes.
[ 16,17 ] A recent study dem-
onstrated the degradation of graphene oxide in the presence
of HRP.
[ 18 ] These studies indicate that enzymatic degradation
depends on the surface functionalization of carbon nanomate-
rials, and requires pretreatment steps, which include exposure
to strong acids and oxidants prior to enzymatic degradation.
Additionally, this degradation process has been reported to be
effective upon continuous exposure of carbon nanomaterials to
enzyme and H
2 O 2 . Thus, peroxidase enzymes could certainly
accelerate degradation of graphene in the presence of H
2 O 2 . [ 18 ]
However, these enzymes are mainly found in the proximity of
certain animal cells (MPO is secreted by infl ammatory cells—
neutrophils), plant cells (HRP is present in the root of horse-
radish plant), or fungi (LiP is found fungi such as Phanerochaete
chrysosporium ). H 2 O 2 , on the other hand, is not restricted to
these bio-organisms but is ubiquitous in eukaryotic cells,
[ 22 ]
and natural resources (fresh and sea water).
[ 32 ] Our results
strongly suggest that alternative degradation mechanism in the
presence H
2 O 2 at physiologically and environmentally relevant
concentrations (1–10 000 × 10
6 M ) could initiate and degrade
single- and multilayered pristine graphene. The limitations of
the above study are: (1) while concentrations of H
2 O 2 mimic
those found in physiological and environmental conditions, the
controlled experimental conditions allow all the available H
2 O 2
to interact with graphene; other competing redox processes
in biological systems or environment that require H
2 O 2 were
absent. The presence of these competing processes will impair
the degradation rate. (2) The studies were performed on multi-
layered sheets of pristine graphene. Thus, this study only pro-
vides insights into the surface degradation effect of H
2 O 2 . Bulk
degradation on macroscopic amount of graphene aggregates in
the presence of H
2 O 2 still needs to be determined.
This work was supported by the National Institutes of Health (grants no.
Part. Part. Syst. Charact. 2014, 31, 745–750
© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
[18] G. P. Kotchey , B. L. Allen , H. Vedala , N. Yanamala , A. A. Kapralov ,
Y. Y. Tyurina , J. Klein-Seetharaman , V. E. Kagan , A. Star , ACS Nano
2011 , 5 , 2098 .
[19] International Agency for Research on Cancer , in IARC Monographs
on the Evaluation of the Carcinogenic Risk of Chemicals to Humans ,
Vol. 35 , 1985 .
[20] Pubchem Compound Summary: Hydrogen Peroxide ,
=784 (accessed August 2013).
[21] Chemical Summary: Hydrogen Peroxide, Environmental Protection
Agency ,;jses
(accessed August 2013).
[22] M. Gulden , A. Jess , J. Kammann , E. Maser , H. Seibert , Free Radic.
Biol. Med. 2010 , 49 , 1298 .
[23] a) H. Nakagawa , K. Hasumi , J. T. Woo , K. Nagai , M. Wachi , Carcino-
genesis 2004 , 25 , 1567 ; b) D. R. Spitz , W. C. Dewey , G. C. Li , J. Cell.
Physiol. 1987 , 131 , 364 .
[24] R. Heyrovska , arXiv:0804.4086 2008 .
[25] M. S. Dresselhaus , A. Jorio , M. Hofmann , G. Dresselhaus , R. Saito ,
Nano Lett. 2010 , 10 , 751 .
[26] J. Russier , C. Menard-Moyon , E. Venturelli , E. Gravel ,
G. Marcolongo , M. Meneghetti , E. Doris , A. Bianco , Nanoscale
2011 , 3 , 893 .
[27] R. P. Vidano , D. B. Fischbach , L. J. Willis , T. M Loehr , Solid State
Commun. 1981 , 39 , 341 .
[28] A. C. Ferrari , J. C. Meyer , V. Scardaci , C. Casiraghi , M. Lazzeri ,
F. Mauri , S. Piscanec , D. Jiang , K. S. Novoselov , S. Roth , A. K. Geim ,
Phys. Rev. Lett. 2006 , 97 , 187401 .
[29] Z. Qu , G. Wang , J. Nanosci. Nanotechnol. 2012 , 12 , 105 .
[30] J. Torreilles , M. C. Guerin , FEBS Lett. 1990 , 272 , 58 .
[31] A. Reina , X. Jia , J. Ho , D. Nezich , H. Son , V. Bulovic ,
M. S. Dresselhaus , J. Kong , Nano Lett. 2009 , 9 , 30 .
[32] a) C. Van Baalen , J. Marler , Nature 1966 , 211 , 951 ; b) D. Price ,
P. J. Worsfold , R. Fauzi , C. Mantoura , Anal. Chim. Acta 1994 , 298 ,
121 .
Part. Part. Syst. Charact. 2014, 31, 745–750
... Previous research indicated that environmentally relevant concentrations of GFNs are in the range of 0.001 to more than 10 mgL − 1 (Ali et al., 2023;Pires et al., 2022;Xing et al., 2014). To the best of the authors' knowledge, no study has evaluated the effects of all three GFNs together at an environmentally relevant dose, despite prior research demonstrating the harmful effects of each GFNs individually at a variety of concentrations. ...
... Several studies have been performed on removing carbon nanomaterials from the environment. The degradation of carbon nanomaterials, such as photodegradation in the presence of UV light, and chemical degradation in the presence of chemicals such as hydrogen peroxide, hypochlorous acid, and Fenton [21][22][23] . The biodegradation of carbon nanomaterials is another considerable removal mechanism. ...
Full-text available
Nanotechnology has increased the release of nanoparticles into the environment, which poses a risk to human health and the ecosystem. Therefore, finding ways to eliminate these hazardous particles from the environment is crucial. This research studied the ability of Trametes versicolor fungi to remove carboxylated multi-walled carbon nanotubes. The study analyzed the impact of pH, MWCNT-COOH concentration, and initial fungal growth time on the removal process. The properties of the adsorbent were measured before and after the biosorption process using SEM, FTIR, and EDS techniques. The results showed that the live biomass of T. versicolor was more effective in removing nanoparticles than dead biomass at 30 °C and pH 7. An increase in carbon nanotube concentration from 5 to 20 mg. mL⁻¹ decreased biosorption potential from 100% to 28.55 ± 1.7%. The study also found that an increase in initial fungal growth time led to higher biomass production and adsorption capacity, increasing biosorption ability for concentrations > 5mg. ml⁻¹. The biosorption kinetics followed a pseudo-second-order model and corresponded most closely to the Freundlich isotherm model. The adsorption capacity of live fungal biomass to remove multi-walled carbon nanotubes was 945.17 mg. g⁻¹, indicating that T. versicolor fungi have significant potential for removing carbon nanostructures from the environment.
... 3D graphene materials exhibit longterm stability in ambient air and maintain their properties over time. Given that these materials are primarily composed of graphene, they share comparable sensitivities to external factors as their 2D graphene counterparts [29][30][31][32]. ...
Full-text available
We use terahertz and multi-terahertz spectroscopy to investigate optical properties of 3D graphene across a wide frequency range of 0.15–10 THz. We explore the electromagnetic shielding, stealth, and absorber capabilities of 3D graphene samples annealed at various temperatures up to 1300 °C. We show that the tradeoff between the transmitted, absorbed and reflected power of the materials can be controlled by the annealing temperature through a fine broadband tuning of the refractive and absorptive indices of the material. This ultralight system (with a specific mass of ∼7 mg cm^(-3)) is capable of acting as a stealth element (non-annealed sample, R<1%), THz absorber (annealing at 750 °C, A>85%) or a shielding coating (annealing at 1300 °C, T<0.1%) within an ultrabroadband range of 0.2–7 THz. All these properties can be combined by stacking these materials on top of each other, which provides unique opportunities for THz applications.
... When these highly oxidative species (OH˙, H˙, OOH˙) are produced in electrochemical systems, either electrochemically or chemically, they immediately affect the catalysts, electrodes, -derived radicals, which did not provide sufficient information regarding the chemical structural changes in the material. 44 It is evident that a substantial knowledge gap exists on the H 2 O 2 -driven performance changes and material degradation process of graphene-based catalysts for electrochemical systems. ...
Full-text available
To develop graphene-based nanomaterials as reliable catalysts for electrochemical energy conversion and storage systems (e.g. PEM fuel cells, metal–air batteries, etc.), it is imperative to critically understand their performance changes and correlated material degradation processes under different operational conditions. In these systems, hydrogen peroxide (H2O2) is often an inevitable byproduct of the catalytic oxygen reduction reaction, which can be detrimental to the catalysts, electrodes, and electrolyte materials. Here, we studied how the electrocatalytic performance changes for a heterogeneous nanocatalyst named nitrogen-doped graphene integrated with a metal–organic framework (N-G/MOF) by the effect of H2O2, and correlated the degradation process of the catalyst in terms of the changes in elemental compositions, chemical bonds, crystal structures, and morphology. The catalyst samples were treated with five different concentrations of H2O2 to emulate the operational conditions and examined to quantify the changes in electrocatalytic performances in an alkaline medium, elemental composition and chemical bonds, crystal structure, and morphology. The electrocatalytic performance considerably declined as the H2O2 concentration reached above 0.1 M. The XPS analyses suggest the formation of different oxygen functional groups on the material surface, the breakdown of the material's C–C bonds, and a sharp decline in pyridinic-N functional groups due to gradually harsher H2O2 treatments. In higher concentrations, the H2O2-derived radicals altered the crystalline and morphological features of the catalyst. Keywords: Nitrogen-doped graphene-based electrocatalyst; Metal–organic framework; Hydrogen peroxide effect on catalyst; Electrocatalytic performance; Material degradation.
... Besides toxicity, the rate at which graphene degrades in vivo is of paramount importance. Given the widespread presence of H 2 O 2 , a strong oxidizing agent, in the body and environment, the rate of degradation of graphene was found to depend on H 2 O 2 concentration [69]. In addition, holes or defect sites were first generated by random attack of H 2 O 2 , followed by a progressive destruction of carboncarbon bonds of graphene around the initial defect sites. ...
Nanoscale biomaterials have garnered immense interest in the scientific community in the recent decade. This review specifically focuses on the application of three nanomaterials, i.e., graphene and its derivatives (graphene oxide, reduced graphene oxide), carbon nanotubes (CNTs) and nanocellulose (cellulose nanocrystals or CNCs and cellulose nanofibers or CNFs), in regenerating different types of tissues, including skin, cartilage, nerve, muscle and bone. Their excellent inherent (and tunable) physical, chemical, mechanical, electrical, thermal and optical properties make them suitable for a wide range of biomedical applications, including but not limited to diagnostics, therapeutics, biosensing, bioimaging, drug and gene delivery, tissue engineering and regenerative medicine. A state-of-the-art literature review of composite tissue scaffolds fabricated using these nanomaterials is provided, including the unique physicochemical properties and mechanisms that induce cell adhesion, growth, and differentiation into specific tissues. In addition, in vitro and in vivo cytotoxic effects and biodegradation behavior of these nanomaterials are presented. We also discuss challenges and gaps that still exist and need to be addressed in future research before clinical translation of these promising nanomaterials can be realized in a safe, efficacious, and economical manner.
... Given the toxicity of accumulated graphene, it is important for graphene nanoparticles to be excreted from the body. Hydrolytic and enzymatic degradation with enzymes such as myeloperoxidase, horseradish peroxidase, and lignin peroxidase have been found to be effective in degrading GO, especially in the presence of low concentrations of hydrogen peroxide [197][198][199][200]. Neutrophils and macrophages have also been reported to cause the degradation of graphene, which indicates the importance of the immune system in mediating the effects of graphene in the body. ...
Full-text available
This paper builds on the context and recent progress on the control, reproducibility, and limitations of using graphene and graphene-related materials (GRMs) in biomedical applications. The review describes the human hazard assessment of GRMs in in vitro and in vivo studies, highlights the composition–structure–activity relationships that cause toxicity for these substances, and identifies the key parameters that determine the activation of their biological effects. GRMs are designed to offer the advantage of facilitating unique biomedical applications that impact different techniques in medicine, especially in neuroscience. Due to the increasing utilization of GRMs, there is a need to comprehensively assess the potential impact of these materials on human health. Various outcomes associated with GRMs, including biocompatibility, biodegradability, beneficial effects on cell proliferation, differentiation rates, apoptosis, necrosis, autophagy, oxidative stress, physical destruction, DNA damage, and inflammatory responses, have led to an increasing interest in these regenerative nanostructured materials. Considering the existence of graphene-related nanomaterials with different physicochemical properties, the materials are expected to exhibit unique modes of interactions with biomolecules, cells, and tissues depending on their size, chemical composition, and hydrophil-to-hydrophobe ratio. Understanding such interactions is crucial from two perspectives, namely, from the perspectives of their toxicity and biological uses. The main aim of this study is to assess and tune the diverse properties that must be considered when planning biomedical applications. These properties include flexibility, transparency, surface chemistry (hydrophil–hydrophobe ratio), thermoelectrical conductibility, loading and release capacity, and biocompatibility.
Full-text available
Nanomaterials (NMs) are becoming more commonly used in microalgal biotechnology to empower the production of algal biomass and valuable metabolites, such as lipids, proteins, and exopolysaccharides. It provides an effective and promising supplement to the existing algal biotechnology. In this review, the potential for NMs to enhance microalgal growth by improving photosynthetic utilization efficiency and removing reactive oxygen species is first summarized. Then, their positive roles in accumulation, bioactivity modification, and extraction of valuable microalgal metabolites are presented. After the application of NMs in microalgae cultivation, the extracted metabolites, particularly exopolysaccharides, contain trace amounts of NM residues, and thus, the impact of these residues on the functional properties of the metabolites is also evaluated. Finally, the methods for removing NM residues from the extracted metabolites are summarized. This review provides insights into the application of nanotechnology for sustainable production of valuable metabolites in microalgae and will contribute useful information for ongoing and future practice.
Graphene oxide (GO) and reduced graphene oxide (rGO) are both widely applicable and there is a massive production throughout the world which imply in inevitable contamination in the aquatic environment by their wastes. Nevertheless, information about their interaction at the cellular level in fish is still scarce. We investigated the metabolic activity, reactive oxygen species (ROS) production, responses of antioxidant defenses, and total antioxidant capacity (TAC) as well as oxidative stress and DNA integrity in zebrafish liver cells (ZFL) exposed to (0.001, 0.01, 0.1 and 1 µg mL-1) of GO and rGO after two exposure period (24 and 72 h). Higher ROS production and no significant changes in the antioxidant defenses resulted in lipid peroxidation in cells exposed to rGO. Cells exposed to GO increased the activity of antioxidant defenses sustaining the TAC and avoiding lipid peroxidation. Comet assay showed that both, GO and rGO, caused DNA strand breaks after 24 h of exposure; however, only rGO caused DNA damage after 72 h of exposure. The exposure to rGO was significantly more harmful to ZFL cells than GO, even at very low concentrations. The cells showed a high capacity to neutralize ROS induced by GO preventing genotoxic effects and metabolic activity, thus sustaining cell viability. The time of exposure had different impacts for both nanomaterials, GO caused more changes in 24 h showing recovery after 72 h, while cells exposed to rGO were jeopardized at both exposure times. These results indicate that the reduction of GO by removal of the oxygen functional groups (rGO) increased toxicity leading to adverse effects in the cells, even at very low concentrations.
Full-text available
This study investigated the degradation of graphene oxide (GO) by the white-rot fungus Phanerochaete chrysosporium . Axenic fungal suspensions were inoculated in malt extract glucose medium enriched with various concentrations of...
Full-text available
In this work, graphene nanoribbons and nanoplatelets were investigated as contrast agents for photoacoustic and thermoacoustic tomography (PAT and TAT). We show that oxidized single- and multi-walled graphene oxide nanoribbons (O-SWGNRs, O-MWGNRs) exhibit approximately 5–10 fold signal enhancement for PAT in comparison to blood at the wavelength of 755 nm, and approximately 10–28% signal enhancement for TAT in comparison to deionized (DI) water at 3 GHz. Oxidized graphite microparticles (O-GMPs) and exfoliated graphene oxide nanoplatelets (O-GNPs) show no significant signal enhancement for PAT, and approximately 12–29% signal enhancement for TAT. These results indicate that O-GNRs show promise as multi-modal PAT and TAT contrast agents, and that O-GNPs are suitable contrast agents for TAT.
Full-text available
We report the synthesis and characterization of a novel carbon nanostructure-based magnetic resonance imaging contrast agent (MRI CA); graphene nanoplatelets intercalated with manganese (Mn(2+)) ions, functionalized with dextran (GNP-Dex); and the in vitro assessment of its essential preclinical physicochemical properties: osmolality, viscosity, partition coefficient, protein binding, thermostability, histamine release, and relaxivity. The results indicate that, at concentrations between 0.1 and 100.0 mg/mL, the GNP-Dex formulations are hydrophilic, highly soluble, and stable in deionized water, as well as iso-osmolar (upon addition of mannitol) and iso-viscous to blood. At potential steady-state equilibrium concentrations in blood (0.1-10.0 mg/mL), the thermostability, protein-binding, and histamine-release studies indicate that the GNP-Dex formulations are thermally stable (with no Mn(2+) ion dissociation), do not allow non-specific protein adsorption, and elicit negligible allergic response. The r 1 relaxivity of GNP-Dex was 92 mM(-1)s(-1) (per-Mn(2+) ion, 22 MHz proton Larmor frequency); ~20- to 30-fold greater than that of clinical gadolinium (Gd(3+))- and Mn(2+)-based MRI CAs. The results open avenues for preclinical in vivo safety and efficacy studies with GNP-Dex toward its development as a clinical MRI CA.
Full-text available
This study investigates the efficacy of two-dimensional (2D) carbon and inorganic nanostructures as reinforcing agents for cross-linked composites of the biodegradable and biocompatible polymer polypropylene fumarate (PPF) as a function of nanostructure concentration. PPF composites were reinforced using various 2D nanostructures: single- and multiwalled graphene oxide nanoribbons (SWGONRs, MWGONRs), graphene oxide nanoplatelets (GONPs), and molybdenum disulfide nanoplatelets (MSNPs) at 0.01-0.2 weight% concentrations. Cross-linked PPF was used as the baseline control, and PPF composites reinforced with single- or multiwalled carbon nanotubes (SWCNTs, MWCNTs) were used as positive controls. Compression and flexural testing show a significant enhancement (i.e., compressive modulus = 35-108%, compressive yield strength = 26-93%, flexural modulus = 15-53%, and flexural yield strength = 101-262% greater than the baseline control) in the mechanical properties of the 2D-reinforced PPF nanocomposites. MSNP nanocomposites consistently showed the highest values among the experimental or control groups in all the mechanical measurements. In general, the inorganic nanoparticle MSNP showed a better or equivalent mechanical reinforcement compared to carbon nanomaterials, and 2D nanostructures (GONPs, MSNPs) are better reinforcing agents compared to one-dimensional (1D) nanostructures (e.g., SWCNTs). The results also indicated that the extent of mechanical reinforcement is closely dependent on the nanostructure morphology and follows the trend nanoplatelets > nanoribbons > nanotubes. Transmission electron microscopy of the cross-linked nanocomposites indicated good dispersion of nanomaterials in the polymer matrix without the use of a surfactant. The sol-fraction analysis showed significant changes in the polymer cross-linking in the presence of MSNP (0.01-0.2 wt %) and higher loading concentrations of GONP and MWGONR (0.1-0.2 wt %). The analysis of surface area and aspect ratio of the nanostructures taken together with the above results indicated differences in nanostructure architecture (2D vs 1D nanostructures), and the chemical compositions (inorganic vs carbon nanostructures), number of functional groups, and structural defects for the 2D nanostructures may be key properties that affect the mechanical properties of 2D nanostructure-reinforced PPF nanocomposites and the reason for the enhanced mechanical properties compared to the controls.
The latest addition to the nanocarbon family, graphene, has been proclaimed to be the material of the century. Its peculiar band structure, extraordinary thermal and electronic conductance and room temperature quantum Hall effect have all been used for various applications in diverse fields ranging from catalysis to electronics. The difficulty to synthesize graphene in bulk quantities was a limiting factor of it being utilized in several fields. Advent of chemical processes and self-assembly approaches for the synthesis of graphene analogues have opened-up new avenues for graphene based materials. The high surface area and rich abundance of functional groups present make chemically synthesized graphene (generally known as graphene oxide (GO) and reduced graphene oxide (RGO) or chemically converted graphene) an attracting candidate in biotechnology and environmental remediation. By functionalizing graphene with specific molecules, the properties of graphene can be tuned to suite applications such as sensing, drug delivery or cellular imaging. Graphene with its high surface area can act as a good adsorbent for pollutant removal. Graphene either alone or in combination with other materials can be used for the degradation or removal of a large variety of contaminants through several methods. In this review some of the relevant efforts undertaken to utilize graphene in biology, sensing and water purification are described. Most recent efforts have been given precedence over older works, although certain specific important examples of the past are also mentioned.
The Raman spectra of crystalline graphite, graphite damaged by ion-etching, and structurally disordered pyrolytic and glassy carbons were examined as a function of excitation wavelength λ over the range 488.0 to 647.1 nm. The bands located at 1360, 2720 and 2950 cm 1 with λ = 488.0 nm undergo a progressive red-shift as λ increases, while the positions of the other major bands (1580 and 1620 cm 1) are invariant. The significance of these observations is briefly discussed.
Herein, a new nanocomposite consisting of up-conversion (UC) material (YF3:Yb3+,Tm3+), TiO2 (P25) and graphene (GR) has been prepared and shown to be an advanced sunlight activated photocatalyst. During the facile hydrothermal method, the reduction of graphene oxide and loading of YF3:Yb3+,Tm3+ and P25 were achieved simultaneously, and the functionalities of each part were integrated together. The as-prepared ternary UC–P25–GR nanocomposite photocatalyst exhibited great adsorptivity of dyes, a significantly extended light absorption range, efficient charge separation properties and superior durability. Indeed, the photocatalytic activity of this novel ternary nanocomposite under sunlight was improved compared with those of P25–GR nanocomposites and bare P25. Overall, this work could provide new insights into the fabrication of ternary composites as high performance photocatalysts and facilitate their application in environmental protection issues.
Development of biocompatible surface coating is critical to engineer various functional nanomaterials for biomedical applications. Here, we present a new surface chemistry of graphene by covalently conjugating graphene oxide (GO) with dextran (DEX), a biocompatible polymer widely used for surface coating of biomaterials. Compared with GO, the graphene–dextran (GO–DEX) conjugate shows reduced sheet sizes, increased thickness and significantly improved stability in physiological solutions. Cellular experiments uncover that DEX coating on GO offers remarkably reduced cell toxicity. We further label GO–DEX with a radioactive isotope, 125I, for in vivo tracking in animal studies. It is found that GO–DEX accumulates in the reticuloendothelial system (RES) including liver and spleen after intravenous injection, and importantly, shows obvious clearance from the mouse body within a week without causing noticeable short-term toxicity to the treated animals. Our results suggest that this DEX coating method on GO may potentially be useful to the further development of novel graphene-based bioconjugates for various biomedical applications.
Graphene oxide (GO) and reduced graphene oxide (RGO) have important applications in the development of new electrode and photocatalyst architectures. Gold nanoparticles (Au NP) are employed as catalyst to assist generation of hydroxyl radicals (OH•) in a UV-peroxide system and further promote the oxidation of RGO. The oxidation of RGO is marked by pores and wrinkles within the 2-D network. Nanosecond flash photolysis used in conjunction with competition kinetics to elucidate the oxidative mechanism and calculate rate constants for the Au NP-catalyzed and direct reaction between RGO and OH• radicals. Through Au NP-mediated oxidation reaction it is possible to tune the properties of RGO through the degree of oxidation and/or functional group selectivity in addition to the nanoporous and wrinkle facets. The ability of Au NP to catalyze the photolytic decomposition of H2O2 as well as the OH• radical-induced oxidation of RGO raises new issues concerning graphene stability in energy conversion and storage (photocatalysis, fuel cells, Li-ion batteries, etc). Understanding RGO oxidation by free radicals will aid in maintaining the long-term stability of RGO-based functional composites where intimate contact with radical species is inevitable.
Graphene quantum dots offer a new approach to quantum nanoelectronics.