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Highly sensitive and selective gas sensor using hydrophilic and hydrophobic graphenes.

Some S, Xu Y, Kim Y, Yoon Y, Qin H, Kulkarni A, Kim T, Lee H - Sci Rep (2013)

Bottom Line: Novel one-headed polymer optical fiber sensor arrays using hydrophilic GO and hydrophobic reduced graphene oxide (rGO) were carefully designed, leading to the selective sensing of volatile organic gases for the first time.The two physically different surfaces of GO and rGO could provide the sensing ability to distinguish between tetrahydrofuran (THF) and dichloromethane (MC), respectively, which is the most challenging issue in the area of gas sensors.The eco-friendly physical properties of GO allowed for faster sensing and higher sensitivity when compared to previous results for rGO even under extreme environments of over 90% humidity, making it the best choice for an environmentally friendly gas sensor.

View Article: PubMed Central - PubMed

Affiliation: NCRI, Center for Smart Molecular Memory, Department of Chemistry, Sungkyunkwan University Suwon, Republic of Korea.

ABSTRACT
New hydrophilic 2D graphene oxide (GO) nanosheets with various oxygen functional groups were employed to maintain high sensitivity in highly unfavorable environments (extremely high humidity, strong acidic or basic). Novel one-headed polymer optical fiber sensor arrays using hydrophilic GO and hydrophobic reduced graphene oxide (rGO) were carefully designed, leading to the selective sensing of volatile organic gases for the first time. The two physically different surfaces of GO and rGO could provide the sensing ability to distinguish between tetrahydrofuran (THF) and dichloromethane (MC), respectively, which is the most challenging issue in the area of gas sensors. The eco-friendly physical properties of GO allowed for faster sensing and higher sensitivity when compared to previous results for rGO even under extreme environments of over 90% humidity, making it the best choice for an environmentally friendly gas sensor.

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Related in: MedlinePlus

Characterization and sensing ability of GO and rGO.High-resolution C 1s XPS spectra for (a), GO and (b), rGO. (c), XRD patterns of GO (black) and rGO (red). (d), TGA plots of GO (black) and rGO (red). Plots of the adsorption and desorption responses of (e), only GO and (f), only rGO POF sensors; the concentration of acetone vapour was varied from 500 ppb to 500 ppm.
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f2: Characterization and sensing ability of GO and rGO.High-resolution C 1s XPS spectra for (a), GO and (b), rGO. (c), XRD patterns of GO (black) and rGO (red). (d), TGA plots of GO (black) and rGO (red). Plots of the adsorption and desorption responses of (e), only GO and (f), only rGO POF sensors; the concentration of acetone vapour was varied from 500 ppb to 500 ppm.

Mentions: A schematic illustration of the experimental setup used to evaluate the sensor performance for VOCs is shown in Fig. 1a, while schematic representations of a POF reflectance probe with GO, rGO and GO-rGO as the selectively sensing layers are shown in Fig. 1b–d. For the POF sensors with one-headed GO and rGO tips, the rGO pattern on the GO was formed simply by exposing the GO layer to sunlight (Fig. 1e)26. For the preparation of the two-headed tip GO/GO, GO/rGO, and rGO/rGO POF sensor array systems, also previously reported solar radiation was applied to prepare rGO layers26. This method was employed to prepare a uniform graphene layer on the POF end face for the sensing studies. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) were employed for characterization of the GO and rGO. Based on the XPS analyses, the as-prepared GO had a very high oxygen atomic percentage (C/O = 2.2). In contrast, the C/O ratio of rGO was 11.6. Based on the XPS data, we concluded that the rGO fabricated from this process contained far less oxygen, which confirmed the high quality of the rGO (Fig. 2a, b). The XRD spectra of the synthesized GO and rGO are shown in Fig. 2c. TGA was used to assess the quality of the rGO when compared to GO. TGA plots of GO (black) and rGO (red) are shown in Fig. 2d. In the case of GO, the majority of the weight was lost between 100 and 200°C, indicating that CO and CO2 were released from the most labile functional groups during pyrolysis. At temperatures below 700°C, the total weight loss of GO was about 72%, while that of rGO was 18.6%.


Highly sensitive and selective gas sensor using hydrophilic and hydrophobic graphenes.

Some S, Xu Y, Kim Y, Yoon Y, Qin H, Kulkarni A, Kim T, Lee H - Sci Rep (2013)

Characterization and sensing ability of GO and rGO.High-resolution C 1s XPS spectra for (a), GO and (b), rGO. (c), XRD patterns of GO (black) and rGO (red). (d), TGA plots of GO (black) and rGO (red). Plots of the adsorption and desorption responses of (e), only GO and (f), only rGO POF sensors; the concentration of acetone vapour was varied from 500 ppb to 500 ppm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3672880&req=5

f2: Characterization and sensing ability of GO and rGO.High-resolution C 1s XPS spectra for (a), GO and (b), rGO. (c), XRD patterns of GO (black) and rGO (red). (d), TGA plots of GO (black) and rGO (red). Plots of the adsorption and desorption responses of (e), only GO and (f), only rGO POF sensors; the concentration of acetone vapour was varied from 500 ppb to 500 ppm.
Mentions: A schematic illustration of the experimental setup used to evaluate the sensor performance for VOCs is shown in Fig. 1a, while schematic representations of a POF reflectance probe with GO, rGO and GO-rGO as the selectively sensing layers are shown in Fig. 1b–d. For the POF sensors with one-headed GO and rGO tips, the rGO pattern on the GO was formed simply by exposing the GO layer to sunlight (Fig. 1e)26. For the preparation of the two-headed tip GO/GO, GO/rGO, and rGO/rGO POF sensor array systems, also previously reported solar radiation was applied to prepare rGO layers26. This method was employed to prepare a uniform graphene layer on the POF end face for the sensing studies. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) were employed for characterization of the GO and rGO. Based on the XPS analyses, the as-prepared GO had a very high oxygen atomic percentage (C/O = 2.2). In contrast, the C/O ratio of rGO was 11.6. Based on the XPS data, we concluded that the rGO fabricated from this process contained far less oxygen, which confirmed the high quality of the rGO (Fig. 2a, b). The XRD spectra of the synthesized GO and rGO are shown in Fig. 2c. TGA was used to assess the quality of the rGO when compared to GO. TGA plots of GO (black) and rGO (red) are shown in Fig. 2d. In the case of GO, the majority of the weight was lost between 100 and 200°C, indicating that CO and CO2 were released from the most labile functional groups during pyrolysis. At temperatures below 700°C, the total weight loss of GO was about 72%, while that of rGO was 18.6%.

Bottom Line: Novel one-headed polymer optical fiber sensor arrays using hydrophilic GO and hydrophobic reduced graphene oxide (rGO) were carefully designed, leading to the selective sensing of volatile organic gases for the first time.The two physically different surfaces of GO and rGO could provide the sensing ability to distinguish between tetrahydrofuran (THF) and dichloromethane (MC), respectively, which is the most challenging issue in the area of gas sensors.The eco-friendly physical properties of GO allowed for faster sensing and higher sensitivity when compared to previous results for rGO even under extreme environments of over 90% humidity, making it the best choice for an environmentally friendly gas sensor.

View Article: PubMed Central - PubMed

Affiliation: NCRI, Center for Smart Molecular Memory, Department of Chemistry, Sungkyunkwan University Suwon, Republic of Korea.

ABSTRACT
New hydrophilic 2D graphene oxide (GO) nanosheets with various oxygen functional groups were employed to maintain high sensitivity in highly unfavorable environments (extremely high humidity, strong acidic or basic). Novel one-headed polymer optical fiber sensor arrays using hydrophilic GO and hydrophobic reduced graphene oxide (rGO) were carefully designed, leading to the selective sensing of volatile organic gases for the first time. The two physically different surfaces of GO and rGO could provide the sensing ability to distinguish between tetrahydrofuran (THF) and dichloromethane (MC), respectively, which is the most challenging issue in the area of gas sensors. The eco-friendly physical properties of GO allowed for faster sensing and higher sensitivity when compared to previous results for rGO even under extreme environments of over 90% humidity, making it the best choice for an environmentally friendly gas sensor.

Show MeSH
Related in: MedlinePlus