Limits...
Fabrication of SnO₂-reduced graphite oxide monolayer-ordered porous film gas sensor with tunable sensitivity through ultra-violet light irradiation.

Xu S, Sun F, Yang S, Pan Z, Long J, Gu F - Sci Rep (2015)

Bottom Line: Graphite oxide sheets dispersed in SnSO4 aqueous solution exhibited excellent affinity with template microspheres and were in situ incorporated into the pore walls during UV-induced growth of SnO2.This film was directly used as gas-sensor and was able to display high sensitivity in detecting ethanol gas.This study provides efficient ways of conducting the in situ fabrication of a semiconductor-reduced graphite oxide film device with uniform surface structure and controllable properties.

View Article: PubMed Central - PubMed

Affiliation: School of Chemistry and Environment, South China Normal University, Guangzhou 510006, P. R. China.

ABSTRACT
A new graphene-based composite structure, monolayer-ordered macroporous film composed of a layer of orderly arranged macropores, was reported. As an example, SnO2-reduced graphite oxide monolayer-ordered macroporous film was fabricated on a ceramic tube substrate under the irradiation of ultra-violet light (UV), by taking the latex microsphere two-dimensional colloid crystal as a template. Graphite oxide sheets dispersed in SnSO4 aqueous solution exhibited excellent affinity with template microspheres and were in situ incorporated into the pore walls during UV-induced growth of SnO2. The growing and the as-formed SnO2, just like other photocatalytic semiconductor, could be excited to produce electrons and holes under UV irradiation. Electrons reduced GO and holes adsorbed corresponding negative ions, which changed the properties of the composite film. This film was directly used as gas-sensor and was able to display high sensitivity in detecting ethanol gas. More interestingly, on the basis of SnO2-induced photochemical behaviours, this sensor demonstrated tunable sensitivity when UV irradiation time was controlled during the fabrication process and post in water, respectively. This study provides efficient ways of conducting the in situ fabrication of a semiconductor-reduced graphite oxide film device with uniform surface structure and controllable properties.

No MeSH data available.


Morphologies of composite films and GO sheets.(a) A low magnification SEM image of SnO2-rGO film (Film-1.0) on the whole tube; (b)–(d) SEM images of Film-1.0, Film-0.5, and Film-4.0, respectively; (e) TEM image of Film-1.0; (e) TEM image of pure GO sheets.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4355683&req=5

f3: Morphologies of composite films and GO sheets.(a) A low magnification SEM image of SnO2-rGO film (Film-1.0) on the whole tube; (b)–(d) SEM images of Film-1.0, Film-0.5, and Film-4.0, respectively; (e) TEM image of Film-1.0; (e) TEM image of pure GO sheets.

Mentions: Fig. 3 shows the morphologies of the SnO2-rGO monolayer-ordered porous films fabricated using a PS microsphere (750 nm in diameter) colloidal monolayer template. The total irradiation times, including the first (Fig. 2b) and the second (Fig. 2d) irradiation times, varied from 0.5 to 1.0, 2.0, and 4.0 h to obtain Film-0.5, Film-1.0, Film-2.0, and Film-4.0, respectively. Fig. 3a shows the SEM image of the ceramic tube covered with Film-1.0. The film covered the entire surface of the tube and connected the electrodes on the two ends. The pores in the film were closely arranged in a hexagonal pattern over a large area (Fig. 3b). The pores had circular openings with a diameter of ~ 350 nm and pore walls with a thickness of ~ 20 nm. The center-to-center spacing between the two adjacent pores was maintained at 750 nm, which is equal to the diameter of the template microspheres. Interestingly, some spherical particles with a size of ~ 85 nm were observed to have piled among three adjacent pores (inset of Fig. 3b). The principal morphologies cannot be modified by irradiation time, as shown in Film-0.5 (Fig. 3c) and Film-4.0 (Fig. 3d). Film-4.0 was randomly gashed several times with a sharp blade to investigate the inner morphology of the film further. An empty spherical pore chamber and a demarcation between the porous and particle layers were observed in a certain section (Fig. 3d). TEM image of Film-1.0 scraped off from the ceramic tube was shown in Fig. 3e. On the broken edge, sheet-like composites were found and they should form by the induction of GO sheets. The selected area electron diffraction (SAED) pattern displayed the polycrystalline structure of the composite. The (110), (101) and (211) planes of SnO2 were clearly discerned by the diffraction rings. Contrasting with the SAED pattern of pure GO sheets (inset of Fig. 3f), rGO in the composite could also be discerned. These explained the rGO sheets had been incorporated into the pore walls of the film.


Fabrication of SnO₂-reduced graphite oxide monolayer-ordered porous film gas sensor with tunable sensitivity through ultra-violet light irradiation.

Xu S, Sun F, Yang S, Pan Z, Long J, Gu F - Sci Rep (2015)

Morphologies of composite films and GO sheets.(a) A low magnification SEM image of SnO2-rGO film (Film-1.0) on the whole tube; (b)–(d) SEM images of Film-1.0, Film-0.5, and Film-4.0, respectively; (e) TEM image of Film-1.0; (e) TEM image of pure GO sheets.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4355683&req=5

f3: Morphologies of composite films and GO sheets.(a) A low magnification SEM image of SnO2-rGO film (Film-1.0) on the whole tube; (b)–(d) SEM images of Film-1.0, Film-0.5, and Film-4.0, respectively; (e) TEM image of Film-1.0; (e) TEM image of pure GO sheets.
Mentions: Fig. 3 shows the morphologies of the SnO2-rGO monolayer-ordered porous films fabricated using a PS microsphere (750 nm in diameter) colloidal monolayer template. The total irradiation times, including the first (Fig. 2b) and the second (Fig. 2d) irradiation times, varied from 0.5 to 1.0, 2.0, and 4.0 h to obtain Film-0.5, Film-1.0, Film-2.0, and Film-4.0, respectively. Fig. 3a shows the SEM image of the ceramic tube covered with Film-1.0. The film covered the entire surface of the tube and connected the electrodes on the two ends. The pores in the film were closely arranged in a hexagonal pattern over a large area (Fig. 3b). The pores had circular openings with a diameter of ~ 350 nm and pore walls with a thickness of ~ 20 nm. The center-to-center spacing between the two adjacent pores was maintained at 750 nm, which is equal to the diameter of the template microspheres. Interestingly, some spherical particles with a size of ~ 85 nm were observed to have piled among three adjacent pores (inset of Fig. 3b). The principal morphologies cannot be modified by irradiation time, as shown in Film-0.5 (Fig. 3c) and Film-4.0 (Fig. 3d). Film-4.0 was randomly gashed several times with a sharp blade to investigate the inner morphology of the film further. An empty spherical pore chamber and a demarcation between the porous and particle layers were observed in a certain section (Fig. 3d). TEM image of Film-1.0 scraped off from the ceramic tube was shown in Fig. 3e. On the broken edge, sheet-like composites were found and they should form by the induction of GO sheets. The selected area electron diffraction (SAED) pattern displayed the polycrystalline structure of the composite. The (110), (101) and (211) planes of SnO2 were clearly discerned by the diffraction rings. Contrasting with the SAED pattern of pure GO sheets (inset of Fig. 3f), rGO in the composite could also be discerned. These explained the rGO sheets had been incorporated into the pore walls of the film.

Bottom Line: Graphite oxide sheets dispersed in SnSO4 aqueous solution exhibited excellent affinity with template microspheres and were in situ incorporated into the pore walls during UV-induced growth of SnO2.This film was directly used as gas-sensor and was able to display high sensitivity in detecting ethanol gas.This study provides efficient ways of conducting the in situ fabrication of a semiconductor-reduced graphite oxide film device with uniform surface structure and controllable properties.

View Article: PubMed Central - PubMed

Affiliation: School of Chemistry and Environment, South China Normal University, Guangzhou 510006, P. R. China.

ABSTRACT
A new graphene-based composite structure, monolayer-ordered macroporous film composed of a layer of orderly arranged macropores, was reported. As an example, SnO2-reduced graphite oxide monolayer-ordered macroporous film was fabricated on a ceramic tube substrate under the irradiation of ultra-violet light (UV), by taking the latex microsphere two-dimensional colloid crystal as a template. Graphite oxide sheets dispersed in SnSO4 aqueous solution exhibited excellent affinity with template microspheres and were in situ incorporated into the pore walls during UV-induced growth of SnO2. The growing and the as-formed SnO2, just like other photocatalytic semiconductor, could be excited to produce electrons and holes under UV irradiation. Electrons reduced GO and holes adsorbed corresponding negative ions, which changed the properties of the composite film. This film was directly used as gas-sensor and was able to display high sensitivity in detecting ethanol gas. More interestingly, on the basis of SnO2-induced photochemical behaviours, this sensor demonstrated tunable sensitivity when UV irradiation time was controlled during the fabrication process and post in water, respectively. This study provides efficient ways of conducting the in situ fabrication of a semiconductor-reduced graphite oxide film device with uniform surface structure and controllable properties.

No MeSH data available.