вход по аккаунту



код для вставкиСкачать
Accepted Manuscript
Title: Highly sensitive chemiresistive H2 S gas sensor based on
graphene decorated with Ag nanoparticles and charged
Authors: Oleksandr Ovsianytskyi, Yun-Sik Nam, Oleksandr
Tsymbalenko, Phan-Thi Lan, Myoung-Woon Moon,
Kang-Bong Lee
SNB 23432
To appear in:
Sensors and Actuators B
Received date:
Revised date:
Accepted date:
Please cite this article as: Oleksandr Ovsianytskyi, Yun-Sik Nam, Oleksandr
Tsymbalenko, Phan-Thi Lan, Myoung-Woon Moon, Kang-Bong Lee, Highly
sensitive chemiresistive H2S gas sensor based on graphene decorated
with Ag nanoparticles and charged impurities, Sensors and Actuators B:
This is a PDF file of an unedited manuscript that has been accepted for publication.
As a service to our customers we are providing this early version of the manuscript.
The manuscript will undergo copyediting, typesetting, and review of the resulting proof
before it is published in its final form. Please note that during the production process
errors may be discovered which could affect the content, and all legal disclaimers that
apply to the journal pertain.
<DOCHEAD>Research paper
<AT>Highly sensitive chemiresistive H2S gas sensor based on graphene
decorated with Ag nanoparticles and charged impurities
Oleksandr Ovsianytskyia,b, Yun-Sik Namc, Oleksandr Tsymbalenkoa,b,
<AU>Phan-Thi Land, Myoung-Woon Moond, Kang-Bong Leea,*
<AFF>aGreen City Technology Institute, Korea Institute of Science and Technology Hwarangro 14 gil 5, Seoul 02792, Republic of Korea
<AFF>bDepartment of Electronics, Igor Sikorsky Kyiv Polytechnic Institute
<AFF>Peremohy Ave. 37, Kyiv 03056, Ukraine
Advanced Analysis Center, Korea Institute of Science and Technology
Hwarang-ro 14 gil 5, Seoul 02792, Republic of Korea
Computational Science Center, Korea Institute of Science and Technology
Hwarang-ro 14 gil 5, Seoul 02792, Republic of Korea
+82 2 958 5957; fax: +82 2 958 5810.
<ABS-Head><ABS-HEAD>Graphical abstract
<ABS-P><xps:span class="xps_Image">fx1</xps:span>
<ABS-HEAD>Highlights► Chemiresistive H2S sensor based on Ag nanoparticles dopedgraphene was fabricated. ► Doping was performed in aqueous AgNO3 and Fe(NO3)3 by a simple
wet-chemical method. ► The produced graphene sensor can detect ~100 ppb of H2S gas within 6
min. ► The fabricated sensor exhibits excellent selectivity towards H2S gas.
<ABS-P> Herein, we report a highly sensitive and selective H2S gas sensor based on graphene decorated with Ag
nanoparticles (AgNPs) and charged impurities fabricated using a simple wet chemical method. Doping on as-grown
chemical vapor deposited graphene was achieved by immersion in an aqueous solution of AgNO3/Fe(NO3)3 for 4
min followed by the decoration with adsorbed AgNPs and charged impurities. The AgNPs utilized in this process
were formed by the reduction of Ag+ ions, since the Ag+/Ag0 reduction potential is higher than that of Fe3+/Fe0.
<ABS-P>The above treatment changed the electronic properties of graphene, achieving a dramatic resistivity change
in the presence of H2S gas by generating surface sites for its adsorption and dissociation and thus allowing real time
H2S level monitoring at ambient temperature with an immediate response.
<ABS-P>Doped graphene was demonstrated to selectively and repeatedly sense H2S gas within six minutes, with
the limit of detection being below 100 ppb. The corresponding mechanism is believed to feature a charge carrier
density change of graphene to adsorbate charge transfer, with the sensor surface trapping or releasing electrons upon
exposure to H2S gas.
<KWD>Keywords: CVD graphene; chemiresistive sensor; H2S graphene sensor; graphene doping; silver
nanoparticle doping
<H1>1. Introduction
H2S is a highly toxic gas which is usually produced by natural gas plants, sewage plants, and the oil industry. Since
exposure to high levels (100 ppm) of H2S gas can induce an immediate collapse with loss of breathing and has high
death probability, various fluorescence-based probes [1–3] and chemiresistive sensors [48] based on reduced
graphene oxide, carbon nanotubes, and other nanocomposites have been developed for sensitive and selective room
temperature H2S detection. Although graphene can also be utilized for this purpose, successful sensor applications
require its electronic properties to be tuned by various doping methods [9,10]. H2S can be easily adsorbed on
graphene sheets doped with transition metals, which enhance the graphene-H2S interaction energy from 0.1 eV
(pristine graphene) to up to 2 eV [1113]. Moreover, the disorder in graphene plays a fundamental role in
determining its physical properties, with conductivity being affected by charged impurities [14].
Herein, we aimed to fabricate a highly sensitive, selective, and low cost H 2S gas sensor with a fast room temperature
response time, overcoming problems observed for previous sensors [911]. In many cases, the sensitivity,
selectivity, or both of these properties can be enhanced by decorating graphene with metal nanoparticles [12,13] by
using electrochemical methods or simple wet chemical reduction of metal salts [1518]. Herein, metal nanoparticles
for graphene decoration were prepared by the chemical reduction of metal salts. Non-covalent functionalization of
the metal salt modified graphene relies on - interactions or weak van der Waals interactions between sp2 graphene
carbons and metal nanoparticles. In most cases, chemical surface doping does not damage the structure of graphene
and is reversible [19]. Doping of graphene by adsorption of metal nanoparticles does not deteriorate carrier mobility
[20], and graphene defects also play a significant role in the sensing process, achieving H 2S adsorption energies of
up to 0.91 eV [21].
Sensitization by noble metals via chemical and/or electronic interactions is an efficient method for enhancing the
response of graphene toward H2S gas, as indicated by earlier reports on iron or silver doped graphene and
semiconductors used for H2S gas sensing [2226]. Ag+ ions can be reduced to Ag nanoparticles (AgNPs) in a mixed
solution of AgNO3 and Fe(NO3)3 due to the difference of Ag+/Ag0 and Fe3+/Fe0 reduction potentials (E) at acidic
pH [27]. In other words, the Ag+ ions of AgNO3 can be converted to AgNPs in the presence of Fe(NO3)3, and the
above nanoparticles can be deposited on the surface of graphene by a simple wet chemical method.
As silver has a high affinity for sulfur, H2S gas is readily adsorbed on the Ag surface. Although the functionalization
of graphene by anchoring AgNPs can theoretically enhance the sensitivity of H 2S gas detection, the weak binding
between Ag adatoms and pristine graphene needs to be examined experimentally, revealing that doping with AgNPs
enables the structurally-favored H2S binding.
Graphene decorated with AgNPs was demonstrated to be an ideal material for the selective and fast H 2S gas sensing
and catalytic dissociation of the adsorbed H2S gas. The excellent sensor performance was a result of graphene and
Ag energy barrier matching upon contact.
The graphene H2S sensor developed in this work exhibited high sensitivity ( 100 ppb), fast response (~1 s), and a
short recovery time (~20 s) at room temperature. The graphene AgNP interface properties were explored by using
X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The
action mode of this sensor was ascribed to the charge transfer and band alignment because of the high carrier
mobility of graphene and the small energy barrier between graphene and AgNP. As a result, the response times were
small and both sensitivity and selectivity were quite high.
<H1>2. Experimental
<H2>2.1. Preparation of chemical vapor deposited (CVD) graphene
Cu foil was immersed in acetone for 30 min and subsequently cleaned in acidic CuSO 4 solution (Figs. 1A, B). In
order to remove copper oxide, the Cu surface was additionally cleaned for 30 min in a furnace heated to 1000 °C at
50 mTorr in a flow of H2 (5 sccm, 30 min). Subsequently, a mixture of CH 4 and H2 (50:5 sccm) in Ar was passed
through the furnace for 30 min at 1000 °C to produce a graphene monolayer (Fig. 1C).
The Cu foil was spin-coated with poly(methyl methacrylate) (PMMA) dissolved in anisole and heated to 100 °C for
15 min (Fig. 1E) for the next transfer step, followed by etching with 98% ammonium persulfate ((NH 4)2S2O8)
solution. Finally, the etched PMMA/graphene was cleaned using deionized water and transferred onto the Si/SiO2
substrates, followed by immersion into acetone for 1 h to remove the PMMA coating (Figs. 1FH).
<H2>2.2. Preparation of CVD graphene doped with AgNPs and charged impurities
CVD graphene was immersed in a solution containing 34.4 wt% of AgNO 3, 8 wt% of Fe(NO3)39H2O, and 2.8 wt%
of 70% HNO3, and the mixture was stirred for 4 min at 20 °C and 1150 rpm. The composition of the above solution
was optimized by measuring the resistivity and response time of doped graphene in the presence of H 2S. Finally, the
samples were dried in an oven for 2 h at 100 °C (Fig. 1I).
<H2>2.3. Characterization of decorated graphene
The surface of doped graphene was examined by optical microscopy (Leica DM2700M, Germany), with phase
transition analysis carried out using XRD (Dmax2500, Rigaku, Japan). Compositional analysis was performed by
XPS (PHI 5000 VersaProbe, Ulvac-PHI, Japan) and SEM (FEI, Inspect F, Oregon, USA) coupled with energy
dispersive X-ray spectrometry (EDS). Raman spectra (Reinshaw, Gloucestershire, UK) were recorded in the range
of 1300–3000 cm−1. High resolution images of pristine and doped graphene were obtained by using a transmission
electron microscope (TEM; FEI Talos, Oregon, USA) coupled with EDS.
<H2>2.4. Gas sensing setup
H2S was mixed with Ar using a gas diluter and further diluted by using an argon balloon (Ar purity: 99.999%). The
flow rates of diluted H2S and Ar were regulated by an in-house built mass flow controller, with the total gas flow
rate maintained at 5 Lmin1. In H2S sensing experiments, the sensor was initially exposed to ambient air to record
the baseline resistivity, followed by exposure to H2S and 25 s purging with air at 60 °C for fast recovery.
<H1>3. Results and discussion
<H2>3.1. Characterization of doped graphene
The surface structure and elemental distribution were examined by SEM, which revealed that pristine graphene
grown on Cu foil showed a uniform, smooth, and flat surface (Fig. 2A), in contrast to doped graphene, for which a
large number of 10–100 nm particles uniformly distributed on its surface (Fig. 2B) were detected. Moreover, EDS
elemental mapping confirmed the presence of Ag and Fe (Fig. 2C) on the surface of doped graphene.
AgNPs were formed on graphene by the reduction of Ag + ions in a solution of AgNO3 and Fe(NO3)3 at acidic pH,
since the reduction potentials (E) of Ag+/Ag0 and Fe3+/Fe0 equal +0.80 and 0.04 V, respectively [24]. In other
words, Fe3+ ions can act as a reducing agent for Ag+ ions due to the difference in their reduction potentials. Thus,
pristine graphene could be easily doped with AgNPs and charged impurities by a simple wet chemical method.
The morphology of doped graphene was characterized by TEM, which showed that the AgNPs had a size of 10–30
nm (Figs. 3A and 3B). High resolution (HR)-TEM imaging (Fig. 3B) demonstrated that most lattice fringes
corresponded to (111) and (200) Ag nanocrystal planes with spacings of 0.23 and 0.2 nm, respectively, confirming
that the surface of graphene was doped with AgNPs. The selected area diffraction (SAED) pattern of polycrystalline
rings (Fig. 3C) revealed the nanocrystalline structure of composite AgNPs with a small amount of Fe impurities.
Raman spectroscopy is one of the most sensitive techniques for characterizing disordered sp2 carbon in graphene.
When scrutinized closely, the subtle differences between pristine and doped graphene provided important
information on their physical properties. As both G and 2D bands are strongly influenced by the charge carrier
concentration, they are typically considered for characterization of doped materials [28]. Figure 4 shows the Raman
spectra of pristine and doped graphene, with the D band (~1345 cm–1) of the former indicating a slight disorder. The
sharp peak at ~1585 cm–1 corresponds to the G band, which involves in-plane vibrations of sp2 carbons.
Furthermore, the intensity of this band is highly sensitive to the number of layers present in the sample, and its exact
position is affected by doping. As the difference in band positions for pristine (1588 cm–1) and doped (1592 cm1)
graphene equaled ~4 cm1, it confirmed that its immersion into a mixed salt solution resulted in doping. It is known
that the Raman shift increases concomitantly with the concentration of holes [28]. All sp2 carbon materials exhibited
a strong peak in the range of 25002800 cm1, which corresponded to the 2D band (~2680 cm1) caused by
electronic band splitting in single layer graphene [2932]. The increased intensity of the upshifted and softened G
band in the doped sample implied p-type doping [33]. The ratio of 2D and G band intensities (I2D/IG) for pristine and
doped graphene equaled 2.70 and 2.46, respectively, corresponding to monolayer graphene [32,34]. Thus, the
decrease in the I2D/IG ratio after deposition of AgNPs on graphene implied that doping had taken place.
The XPS spectra of pristine and doped graphene are shown in Figs. 5AC. The high resolution spectrum of doped
graphene suggests that AgNPs and charged impurities are uniformly distributed throughout the sample.
Additionally, prominent Ag 3d and Fe 2p peaks cab be observed for doped graphene, with Fe present in the form of
FeO (709.8 eV), Fe2O3 (711.4 eV), and FeOOH (713.3 eV) (Fig. 5B), and Ag present as metallic Ag (368.3 and
374.4 eV), AgO (367.3 eV), and Ag2O (373.3 eV) (Fig. 5C). The XRD patterns recorded for the surface of doped
graphene (Fig. 5D) and the Miller indices (111, 200, 220, 311, and 222) of the observed peaks clearly indicated the
presence of crystalline AgNPs. Moreover, an additional (220) peak revealed the presence of a small amount of a
charged Fe impurity in one crystallographic orientation.
It was concluded that these AgNPs were anchored on the surface of graphene, since the AgCO peak could be
clearly observed in the energy range of the C 1s signal in the high-resolution XPS spectrum (not shown).
<H2>3.2. H2S sensing properties of AgNP doped graphene
The adsorption of oxygen and water vapor on the surface of graphene under ambient conditions leads to p-type
doping because of free electron trapping [35]. In view of the high H 2S affinity to Ag and Fe compounds, the
mechanism of H2S sensing by doped graphene can be described in terms of the core adsorption sites provided by the
graphene dopants [34,36]. Upon interaction with dopants on the surface of graphene, H 2S molecules are cleaved by
the metal nanoparticles acting as catalysts, concomitant with the adsorption of oxygen ions. This dissociation of H 2S
molecules changes the concentration of the charge carriers in the graphene sensor. Since the doped graphene used
herein was a p-type semiconductor, the release of free electrons reduced the number of holes because of charge
recombination, thus increasing resistivity.
The sensing mechanism can be described by the following steps [36,37]:
O2 (gas) → O2 (ads)
O2 (ads) + e− → O2− (ads) (2)
2H2S + 3O2− (ads) → 2H2O↑ + 2SO2↑ + 3e− (3)
Exposure of the sensor to an oxidizing gas (e.g., O2) triggers reaction (2). As described earlier, O2 acts as a charge
acceptor, removing electrons from the surface of graphene and thus decreasing its resistance. When the surface is
exposed to H2S, the adsorption of the gas likely initiates because of its interaction with the adsorbed oxygen species
on Ag and not C, as the former is less electronegative than the latter. The adsorption of H 2S results in its eventual
dissociation, and SO2 and H2O are formed with the release of electrons. These released electrons are fed back into
graphene, where they recombine with intrinsic holes. This phenomenon decreases the charge carrier concentration,
and results in an increase in the resistance of Ag-doped graphene (Scheme 1).
Doping of semiconductors is usually achieved by incorporating appropriate atoms into the host lattice of the
semiconductor to generate positive charge carriers-holes-in the semiconductor. When the dopants are distributed
inhomogeneously in the semiconductor lattice, mobile charge carriers are produced and the electric field acts on
them [38]. Thus, inhomogeneous doping results in local variations of hole concentrations. The response of the
sensor toward 500 ppb of H2S was tested as a function of graphene immersion time (Fig. S1), revealing that
optimum sensing was achieved after 4 min of immersion. Apparently, these four minutes are sufficient for
inhomogeneous doping to proliferate the charge carriers.
3.3. Sensitivity and selectivity of H2S detection
Fig. 6A illustrates the relative responses of pristine graphene (reference response), graphene doped with
Fe(NO3)3 solution, graphene doped with AgNO 3 solution, and graphene doped with a mixed AgNO3/Fe(NO3)3
solution to 500 ppb of H2S. After 400 s of exposure time to H2S, the relative responses of graphene doped with sole
Fe(NO3)3 and AgNO3 solutions increased to ~1.5 and 5% compared to that of pristine graphene, respectively. The
relative response of AgNO3doped graphene seemed to be slightly better than that of Fe(NO3)3doped graphene,
since Ag can provide more favorable H2S adsorption sites compared to Fe.
After 360 s of exposure to H2S, the relative responses of graphene doped with the mixed solution increased
dramatically to ~37% in comparison with that of pristine graphene. Additionally, such hybrid composite doping
resulted in a very fast recovery time upon hot air purging. Fig. 6B represents the sensor response as a function of
H2S concentration, with the relative response measuring time set to ~350 s for each concentration. The prepared
sensor showed excellent relative responses and response linearity (10, 21, 37, 53, 65, and 137% at 0.1, 0.2, 0.5, 1.0,
5.0, 10, and 50 ppm of H2S, respectively), as shown in Fig. 6C. Furthermore, the relative responses were measured
four times at three different concentrations of H2S gas (not shown). These experiments showed good repeatability,
which were ~3.48, ~2.89, and ~4.58 % for 0.5, 1.0, and 5.0 ppm concentration of H 2S gas, respectively.
Sensor selectivity was also tested using different gases, with the corresponding responses (Fig. 7) revealing excellent
selectivity for H2S in the presence of CH4, CO2, N2, and O2 that are typically generated during biogas production.
For example, sensor responses of 0.65, 0.55, and 0.50% were observed for 100, 75, and 50% of CH4, respectively,
with responses for 50 and 25% CO2 equaling 0.70 and 0.55%, respectively. Moreover, 100% O 2 and 10% of N2 did
not give rise to any visible change in the electrical properties of the sensor. In other words, CH 4, CO2, O2, and N2
gases produced only negligible sensor responses, implying that other gases present in high concentrations would not
interfere with H2S quantitation using the developed graphene sensor (Fig. S2).
The relative resistivity responses were measured using 10 ppm of H 2S to test the long-term stability of this sensor,
which was found to be very stable in the range of  3% for at least 8 weeks (not shown).
<H2>3.4. Fabrication and testing of a chemiresistive graphene based sensor
The graphene sensor, built as a chemiresistor because of the high sensitivity and simplicity of this design, was
comprised of doped graphene on a SiO2/Si substrate, which acted as a sensing material bridging the gap between the
two silver electrodes. The sensor was mounted on a plastic framework, with silver electrodes connecting graphene
with the electrical resistance measurement system. Two in-house built electrodes were used instead of sputtering an
interdigitated transducer array using costly photolithography equipment. The fabricated chemiresistive graphene
sensor system is displayed in Fig. 8A, with a schematic setup for H 2S quantitation presented in Fig. 8B. The sensor
assembly was placed into a sealed glass flask with a gas inlet/outlet (Fig. 8B) and connected to a
potentiostat/galvanostat (VersaSTAT 3, Ametec Inc., Berwyn, PA, USA) interfaced with a personal computer.
The inherent resistance of a chemiresistor can be modulated by exposure to the analyte gas, because it is
proportional to the concentration of the gas molecules. Hence, the concentration of H2S was quantified by measuring
the change in relative resistivity as a function of time. The relative sensor response (R) was expressed as a
percentage: R (%) = (Rr  Ri)/Ri × 100%, where Rr is the maximum sensor resistivity measured in the presence of
H2S, and Ri is the initial sensor resistivity in the absence of the analyte.
<H1>4. Conclusion
Single layer CVD graphene was treated with a solution of AgNO3 and Fe(NO3)3, resulting in doping with AgNPs
and a number of charged impurities. These dopants generated H2S adsorption and dissociation sites on the surface of
graphene, allowing us to monitor H2S concentration in real time and achieving an immediate response at ambient
temperature. Thus, doped graphene was used to fabricate a more sensitive and selective H2S sensor compared to that
produced using pristine graphene.
The change in the resistance of doped graphene, R = 37%, observed for 350 s exposure to 500 ppb H 2S revealed that
H2S concentrations much lower than 100 ppb could be measured in the presence of other gases if the standard H 2S
gas could be diluted to levels below 100 ppb. Currently, further optimization of the composition and deposition of
nanocomposite graphene dopants is in progress.
This research was financially supported by the Korea Institute of Science and Technology
(2E27070 and 2E27080), and Korea Ministry of Environment (2016000160008) as a ``Public
Technology Program Based on Environmental Policy''.
[1] J. Kang, F. Huo, P. Ning, X. Meng, J. Chao, C. Yin,;1; Two red-emission single and double `arms' fluorescent
materials stemmed from `one-pot' reaction for hydrogen sulfide vivo imaging, Sens. Actuators B 250 (2017) 342–
[2] F. Huo, Y. Zhang, P. Ning, X. Meng, C. Yin,;1; A novel isophorone-based red-emitting fluorescent probe for
selective detection of sulfide anions in water for in vivo imaging, J. Mater. Chem. B 5 (2017) 2798–2803.
[3] J. Li, C. Yin, F. Huo,;1; Chromogenic and fluorogenic chemosensors for hydrogen sulfide: review of detection
mechanisms since the year 2009, RSC Adv. 5 (2015) 2191–2206.
[4] M. MalekAlaiea, M. Jahangiri, A.M. Rashidib, A. HaghighiAsl, N. Izadi,;1; Selective hydrogen sulfide (H 2S)
sensors based on molybdenum trioxide (MoO3) nanoparticle decorated reduced graphene oxide, Mater. Sci.
Semicond. Process. 38 (2015) 93–100.
[5] H. Liu, W. Zhang, H. Yu, L. Gao, Z. Song, S. Xu, M. Li, Y. Wang, H. Song, J. Tang,;1; Solution-processed gas
sensors employing SnO2 quantum dot/MWCNT nanocomposites, ACS Appl. Mater. Interfaces 8 (2016) 840−846.
[6] Z. Song, Z. Wei, B. Wang, Z. Luo, S. Xu, W. Zhang, H. Yu, M. Li, Z. Huang, J. Zang, F. Yi, H. Liu,;1; Sensitive
room-temperature H2S gas sensors employing SnO2 quantum wire/reduced graphene oxide nanocomposites, Chem.
Mater. 28 (2016) 1205−1212.
[7] Z. Song, J. Liu, Q. Liu, H. Yu, W. Zhang, Y. Wang, Z. Huang, J. Zang, H. Liu,;1; Enhanced H2S gas sensing
properties based on SnO2 quantum wire/reduced graphene oxide nanocomposites: Equilibrium and kinetics
modeling, Sens. Actuators B 249 (2017) 632−638.
[8] A. Fattah, S. Khatami,;1; Selective H2S gas sensing with a graphene/n-Si Schottky Diode, IEEE Sens. J. 14
(2014) 4104–4108.
[9] Y.-H. Zhang, Y.-B. Chen, K.-G. Zhou, C.-H. Liu, J. Zeng, H.-L. Zhang, Y. Peng,;1; Improving gas sensing
properties of graphene by introducing dopants and defects: a first-principles study, Nanotechnology 20 (2009)
[10] S.S. Varghese, S. Lonkar, K.K. Singh, S. Swaminathan, A. Abdala,;1; Recent advances in graphene based gas
sensors, Sens. Actuators B 218 (2015) 160–183.
[11] A.H. Reshak, S. Auluck,;1; Adsorbing H2S onto a single graphene sheet: A possible gas sensor, J. Appl. Phys.
116 (2014) 103702.
[12] R.J. Toh, H.L. Poh, Z. Sofer, M. Pumera,;1; Transition metal (Mn, Fe, Co, Ni)-doped graphene hybrids for
electrocatalysis, Chem. Asian J. 8 (2013) 1295–1300.
[13] H. Zhang, X. Luo, H. Song, X. Lin, X. Lu, Y. Tang,;1; DFT study of adsorption and dissociation behavior of
H2S on Fe-doped graphene, Appl. Surf. Sci. 317 (2014) 511–516.
[14] Y.-H. Zhang, L.-F. Han, Y.-H. Xiao, D.-Z. Jia, Z.-H. Guo, F. Li,;1; Understanding dopant and defect effect on
H2S sensing performances of graphene: A first-principles study, Comput. Mater. Sci. 69 (2013) 222–228.
[15] V. Chakrapani, J.C. Angus, A.B. Anderson, S.D. Wolter, B.R. Stoner, G.U. Sumanasekera,;1; Charge transfer
equilibria between diamond and an aqueous oxygen electrochemical redox couple, Science 318 (2007) 1424–1430.
[16] J. Ristein,;1; Surface transfer doping of semiconductors, Science 313 (2006) 1057–1058.
[17] F. Maier, M. Riedel, B. Mantel, J. Ristein, L. Ley,;1; Origin of surface conductivity in diamond, Phys. Rev.
Lett. 85 (2000) 3472–3475.
[18] H. Liu, Y. Liu, D. Zhu,;1; Chemical doping of graphene, J. Mater. Chem. 21 (2011) 3335–3345.
[19] F. Schedin, A.K. Geim, S.V. Morozov, E.W. Hill, P. Blake, M.I. Katsnelson, K.S. Novoselov,;1; Detection of
individual gas molecules adsorbed on graphene, Nat. Mater. 6 (2007) 652–655.
[20] Y. Song, W. Fang, A. L. Hsu, J. Kong,;1; Iron(III) chloride doping of CVD graphene, Nanotechnology 25
(2014) 395701.
[21] Z. Jiang, J. Li, H. Aslan, Q. Li, Y. Li, M. Chen, Y. Huang, J.P. Froning, M. Otyepka, R. Zboril, F.
Besenbacherb, M. Dong,;1; A high efficiency H2S gas sensor material: paper like Fe2O3/graphene nanosheets and
structural alignment dependency of device efficiency, J. Mater. Chem. A 2 (2014) 6714–6717.
[22] K.S. Yoo, S.D. Han, H.G. Moon, S.-J. Yoon, C.-Y. Kang,;1; Highly Sensitive H2S Sensor Based on the MetalCatalyzed SnO2 Nanocolumns Fabricated by Glancing Angle Deposition, Sensors 15 (2015) 15468–15477.
[23] J.-W. Yoon, Y.J. Hong, Y.C. Kang, J.-H. Lee,;1; High performance chemiresistive H2S sensors using Agloaded SnO2 yolk–shell nanostructures, RSC Adv. 4 (2014) 16067–16074.
[24] Y. Wang, Y. Wang, J. Cao, F. Kong, H. Xia, J. Zhang, B. Zhu, S. Wang, S. Wu,;1; Low-temperature H2S
sensors based on Ag-doped Fe2O3 nanoparticles, Sens. Actuators B 131 (2008) 183–189.
[25] K. Novoselov, A. Geim, S. Morozov, D. Jiang, Y. Zhang, S. Dubonos, I. Grigorieva, A. Firsov,;1; Electric field
effect in atomically thin carbon films, Science 306 (2004) 666–669.
[26] M.S. Dresselhaus, P. T. Araujo,;1; Perspectives on the 2010 Nobel Prize in physics for graphene, ACS Nano 4
(2010) 6297–6302.
[27] E.M. Córdoba, J.A. Muñoz, M.L. Blázquez, F. González, A. Ballester,;1; Leaching of chalcopyrite with ferric
ion. Part III: Effect of redox potential on the silver-catalyzed process, Hydrometallurgy 93 (2008) 97–105.
[28] R. Beams, L.G. Cancado, L. Novotny,;1; Raman characterization of defects and dopants in graphene, J. Phys.:
Condens. Matter 27 (2015) 083002.
[29] X. Li, W. Cai, J. An, S. Kim, J. Nah, D. Yang, R. Piner, A. Velamakanni, I. Jung, E. Tutuc, S.K. Banerjee, L.
Colombo, R.S. Ruoff,;1; Large-area synthesis of high-quality and uniform graphene films on copper foils, Science
324 (2009) 1312–1314.
[30] B. Cho, J. Yoon, M.G. Hahm, D.H. Kim, A.R. Kim, Y.H. Kahng, S.W. Park, Y.J. Lee, S.G. Park, J.D. Kwon,
C.S. Kim, M. Song, Y. Jeong, K.S. Nam, H.C. Ko,;1; Graphene-based gas sensor: metal decoration effect and
application to a flexible device, Mater. Chem. C 27 (2014) 5280–5285.
[31] H. Liu, Y. Liu, D. Zhua,;1; Chemical doping of graphene, J. Mater. Chem. 21(2011) 3335–3345.
[32] T. Oh,;1; CVD graphene synthesis on copper foils and doping effect by nitric acid, Trans. Electr. Electron.
Mater. 5 (2013) 246–249.
[33] H. Liu, Y. Liu, D. Zhua,;1; Chemical doping of graphene, J. Mater. Chem. 21 (2011) 3335–3345.
[34] Y. Wang, Y. Wang, J. Cao, F. Kong, H. Xia, J. Zhang, B. Zhu, S. Wang, S. Wu,;1; Low-temperature H2S
sensors based on Ag-doped α-Fe2O3 nanoparticles, Sens. Actuators B 131 (2008) 183–189.
[35] C.Y. Sung, S.A. Hashimi, A. McCormick, M. Tsapatsis, M. Cococcioni,;1; Density functional theory study on
the adsorption of H2S and other Claus process tail gas components on copper- and silver-exchanged Y zeolites, J.
Phys. Chem. C 116 (2012) 3561–3575.
[36] F.C. Fabiani, G. Fratesi, G.P. Brivio,;1; Adsorption of H2S, HS, S, and H on a stepped Fe(310) surface, Eur.
Phys. J. B 78 (2010) 455–460.
[37] V. X. Hien, Y.-W. Heo,;1; Effects of violet-, green-, and red-laser illumination on gas-sensing properties of
SnO thin film, Sens. Actuators B 228 (2016) 185–191.
[38] J. Ristein,;1; Surface transfer doping of semiconductors, Science 313 (2006) 1057–1058.
[39] M. K. Verma, V. Gupta,;1; A highly sensitive SnO2–CuO multilayered sensor structure for detection of H2S
gas, Sens. Actuators B 166–167 (2012) 378–385.
[40] Y. Zhao, X. He, J. Li, X. Gao, J. Jia,;1; Porous CuO/SnO2 composite nanofibers fabricated by electrospinning
and their H2S sensing properties, Sens. Actuators B 165 (2012) 82–87.
[41] C. Wang, X. Chu, M. Wu,;1; Detection of H2S down to ppb levels at room temperature using sensors based on
ZnO nanorods, Sens. Actuators B 113 (2006) 320–323.
[42] L. Mai, L. Xu, Q. Gao, C. Han, B. Hu, Y. Pi, Single;1; β-AgVO3 Nanowire H2S Sensor, Nano Lett. 10 (2010)
[43] X. Li, Y. Wang, Y. Lei, Z. Gu,;1; Highly sensitive H2S sensor based on template-synthesized CuO nanowires,
RSC Adv. 2 (2012) 2302–2307.
Author Biographies
Ovsianytskyi Oleksandr is currently an MS student studying on the fabrication of
chemiresistive graphene sensor and characterization of graphene doped with nanoparticles in
Korea Institute of Science and Technology.
Yun-Sik Nam is a senior research scientist working on fabrication of nanoparticle colorimetric
sensor and fluorescence sensors in Korea Institute of Science and Technology. His research
interests cover analytical chemistry and sensor fabrication on hazardous chemicals.
Ovsianytskyi Tsymbalenko is currently an MS student studying on the fabrication of
chemiresistive graphene sensor and characterization of graphene doped with nanoparticles in
Korea Institute of Science and Technology.
<BIO>Phan-Thi Lan is currently a Ph.D. student studying on fabrication of CVD grown
graphene and characterization of metal doped graphene in Korea Institute of Science and
<BIO>Myoung-Woon Moon is a principal researcher working on surface modification,
biomaterials, and porous materials in Korea Institute of Science and Technology. His research
interests cover characterization and modification for surface of thin film.
<BIO>Kang-Bong Lee is a principal investigator and a professor in Korea Institute of Science
and Technology. His current research includes the fabrication of chemiresitive graphene gas
sensor and colorimetric nanoparticle sensor.
<Figure>Fig. 1. Schematic diagram of graphene growth, decoration, and transfer processes. Cleaning of Cu foil
(A) in acetone and (B) in an electrolyte solution. (C) CVD-mediated graphene growth and (D) graphene growth on
copper foil. (E) Spin-coating of PMMA onto the graphene surface. (F) Etching of Cu foil in ammonium persulfate
solution. (G) Transfer of PMMA/graphene onto the Si/SiO 2 substrate after rinsing. (H) Removal of PMMA coating
in acetone and cleaning of graphene deposited on the silicon wafer with distilled water. (I) Soaking of graphene in
aqueous AgNO3 and Fe(NO3)3 at acidic pH with stirring. (J) Oven drying of graphene for 2 h at 100 °C.
<Figure>Fig. 2. (A) SEM image of pristine graphene. (B) SEM image of graphene treated with AgNO 3/Fe(NO3)3
(C) Normalized SEM/EDS spectrum of graphene decorated with AgNPs.
<Figure>Fig. 3. (A) TEM and (B) HR-TEM image of as prepared graphene decorated with AgNPs. (C) Selected
area electron diffraction (SAED) pattern for the circled area in (A).
<Figure>Fig. 4. Raman spectra of (A) pristine graphene (I2D/IG  2.70, G band  1588 cm1) and (B) graphene
immersed in a mixed solution of AgNO 3 and Fe(NO3)3) for 4 min (I2D/IG  2.46, G band  1592 cm1).
<Figure>Fig. 5. (A) Wide scan XPS spectra of pristine graphene (blue line) and graphene doped with AgNPs and
charged impurities (black line). (B) High resolution Fe 2p XPS spectrum for binding energies of 706–717 eV. (C)
High resolution Ag 3d XPS spectrum for binding energies of 365–376 eV. (D) XRD spectra of pristine graphene
(black line) and graphene soaked in 34.4 wt% AgNO3 + 8 wt% Fe(NO3)3 solution (red line).
<Figure>Fig. 6. (A) Relative resistivity responses of pristine graphene (▬), graphene doped with Fe(NO 3)3
solution (▬), graphene doped with AgNO3 solution (▬), and graphene doped with mixed Fe(NO3)3 and AgNO3
solution (▬) in the presence of 500 ppb of H2S gas. (B) Resistivity response curve for various H2S concentrations at
room temperature for graphene doped with a solution of Fe(NO3)3 and AgNO3. (C) Relative resistivity response of
doped graphene as a function of H2S concentration.
<Figure>Fig. 7. Response of graphene sensor for various concentrations of (A) CH 4 (B) CO2, (C) O2, and (D) N2
<Figure>Fig. 8. (A) Schematic representation of the chemiresistive graphene sensor. (B) Schematic experimental
setup for H2S gas sensing (VersaSTAT 3; potentiostat/galvanostat).
<Figure>Scheme 1. Schematic representation of (A) H2S sensing by graphene decorated with AgNO3 and (B)
dissociation of H2S adsorbed on the surface of decorated graphene. EC: conduction band energy, EV: valence band
energy, Bg: band gap.
<Table>Table 1. Comparison of main properties and performance characteristics of nanomaterials used to detect
H2S gas.
Sensing material
Spin coating
23 s
Spin coating
Spin coating
25 s
Schottky diode
Different vacuum and
chemical depositions
20 min
SnO2–CuO multilayer
Pulsed laser deposition
CuO/SnO2 composite
23 s
ZnO nanorods
27 min
Single -AgVO3
20 s
CuO nanowire
50 min
AgNP-doped graphene
Wet-chemical doping
6 min
LOD, limit of detection
Без категории
Размер файла
288 Кб
2017, 128, snb
Пожаловаться на содержимое документа