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High-quality reduced graphene oxide-nanocrystalline platinum hybrid materials prepared by simultaneous co-reduction of graphene oxide and chloroplatinic acid.

Wang Y, Liu J, Liu L, Sun DD - Nanoscale Res Lett (2011)

Bottom Line: The resultant RGO-Pt hybrid materials were characterized using transmission electron microscopy (TEM), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy, and thermogravimetric analysis.Platinum (Pt) nanoparticles were anchored randomly onto the reduced GO (RGO) sheets with average mean diameters of 1.76 (pH 7) and 1.93 nm (pH 10).The significant Pt diffraction peaks and the decreased intensity of (002) peak in the XRD patterns of RGO-Pt hybrid materials confirmed that the Pt nanoparticles were anchored onto the RGO sheets and intercalated into the stacked RGO layers at these two pH values.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Civil and Environmental Engineering, Nanyang Technological University, 639798, Singapore. JCLiu@ntu.edu.sg.

ABSTRACT
Reduced graphene oxide-nanocrystalline platinum (RGO-Pt) hybrid materials were synthesized by simultaneous co-reduction of graphene oxide (GO) and chloroplatinic acid with sodium citrate in water at 80°C, of pH 7 and 10. The resultant RGO-Pt hybrid materials were characterized using transmission electron microscopy (TEM), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy, and thermogravimetric analysis. Platinum (Pt) nanoparticles were anchored randomly onto the reduced GO (RGO) sheets with average mean diameters of 1.76 (pH 7) and 1.93 nm (pH 10). The significant Pt diffraction peaks and the decreased intensity of (002) peak in the XRD patterns of RGO-Pt hybrid materials confirmed that the Pt nanoparticles were anchored onto the RGO sheets and intercalated into the stacked RGO layers at these two pH values. The Pt loadings for the hybrid materials were determined as 36.83 (pH 7) and 49.18% (pH 10) by mass using XPS analysis. With the assistance of oleylamine, the resultant RGO-Pt hybrid materials were soluble in the nonpolar organic solvents, and the dispersion could remain stable for several months.

No MeSH data available.


XRD patterns of RGO-Pt hybrid materials: (a) RGO-NoPt-10, (b) RGO-Pt-7, and (c) RGO-Pt-10.
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Figure 4: XRD patterns of RGO-Pt hybrid materials: (a) RGO-NoPt-10, (b) RGO-Pt-7, and (c) RGO-Pt-10.

Mentions: Figure 4 shows the XRD patterns of the RGO-NoPt-10, RGO-Pt-7, and RGO-Pt-10 powders. In Figure 4a, the characteristic peak at 2θ = 22.6° is ascribed to the (002) planes of the chemically reduced GO stacks [33], indicating the effective reduction of GO by citrate sodium at pH 10. The (002) diffraction intensity of RGO-Pt-7 at 2θ = 22.6° is lower than that of RGO-NoPt-10. Moreover, no obvious (002) diffraction peak is observed in the XRD pattern of RGO-Pt-10 because the regular stacks of RGO are destroyed by the intercalation of Pt nanoparticles [34]. In the XRD patterns of RGO-Pt-7 and RGO-Pt-10, the clear diffraction bands centered at 2θ of 39.9°, 46.3°, 67.7°, and 81.4° are corresponding to the (111), (200), (220), and (311) reflections of Pt nanocrystals [26], respectively. The broadening peaks are caused by the small size of the Pt nanoparticles. The size of the Pt nanoparticles can be estimated by means of the Scherrer equation based on the full-width at half-maximum of Pt (111) peak at 2θ = 39.7°. The calculated average sizes of the Pt nanoparticles are 1.97 and 2.07 nm for RGO-Pt-7 and RGO-Pt-10, respectively, which are in good agreement with TEM observations of this study. Elemental analysis based on the XPS data (Figure 5a) reveals that the O/C atomic ratios are 0.3738, 0.1889, and 0.1816 for GO, RGO-Pt-7, and RGO-Pt-10, respectively. The Pt mass loadings are 36.83 and 49.18% for RGO-Pt-7 and RGO-Pt-10. The reduced O/C atomic ratio and the decrease in the intensity of the O 1 s scan (Figure 5b) indicate the effective reduction of the GO sheets at pH 7 and 10. High-resolution spectra of the C 1 s region in Figure 5c, e-g show that both epoxide and hydroxyl functional groups are considerably decreased for RGO-Pt-7 and RGO-Pt-10. The Pt 4f 7/2 peak and Pt 4f 5/2 peak have been shifted to higher energy levels of 72.4 and 75.6 eV, respectively, for both the samples, which may be due to the interaction between the Pt nanoparticles and the reduced graphene sheets. The existence of Pt 4f signals (Figure 5a, d) observed for RGO-Pt-7 and RGO-Pt-10 further confirms that the RGO-Pt hybrid materials have been synthesized successfully [44].


High-quality reduced graphene oxide-nanocrystalline platinum hybrid materials prepared by simultaneous co-reduction of graphene oxide and chloroplatinic acid.

Wang Y, Liu J, Liu L, Sun DD - Nanoscale Res Lett (2011)

XRD patterns of RGO-Pt hybrid materials: (a) RGO-NoPt-10, (b) RGO-Pt-7, and (c) RGO-Pt-10.
© Copyright Policy - open-access
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Figure 4: XRD patterns of RGO-Pt hybrid materials: (a) RGO-NoPt-10, (b) RGO-Pt-7, and (c) RGO-Pt-10.
Mentions: Figure 4 shows the XRD patterns of the RGO-NoPt-10, RGO-Pt-7, and RGO-Pt-10 powders. In Figure 4a, the characteristic peak at 2θ = 22.6° is ascribed to the (002) planes of the chemically reduced GO stacks [33], indicating the effective reduction of GO by citrate sodium at pH 10. The (002) diffraction intensity of RGO-Pt-7 at 2θ = 22.6° is lower than that of RGO-NoPt-10. Moreover, no obvious (002) diffraction peak is observed in the XRD pattern of RGO-Pt-10 because the regular stacks of RGO are destroyed by the intercalation of Pt nanoparticles [34]. In the XRD patterns of RGO-Pt-7 and RGO-Pt-10, the clear diffraction bands centered at 2θ of 39.9°, 46.3°, 67.7°, and 81.4° are corresponding to the (111), (200), (220), and (311) reflections of Pt nanocrystals [26], respectively. The broadening peaks are caused by the small size of the Pt nanoparticles. The size of the Pt nanoparticles can be estimated by means of the Scherrer equation based on the full-width at half-maximum of Pt (111) peak at 2θ = 39.7°. The calculated average sizes of the Pt nanoparticles are 1.97 and 2.07 nm for RGO-Pt-7 and RGO-Pt-10, respectively, which are in good agreement with TEM observations of this study. Elemental analysis based on the XPS data (Figure 5a) reveals that the O/C atomic ratios are 0.3738, 0.1889, and 0.1816 for GO, RGO-Pt-7, and RGO-Pt-10, respectively. The Pt mass loadings are 36.83 and 49.18% for RGO-Pt-7 and RGO-Pt-10. The reduced O/C atomic ratio and the decrease in the intensity of the O 1 s scan (Figure 5b) indicate the effective reduction of the GO sheets at pH 7 and 10. High-resolution spectra of the C 1 s region in Figure 5c, e-g show that both epoxide and hydroxyl functional groups are considerably decreased for RGO-Pt-7 and RGO-Pt-10. The Pt 4f 7/2 peak and Pt 4f 5/2 peak have been shifted to higher energy levels of 72.4 and 75.6 eV, respectively, for both the samples, which may be due to the interaction between the Pt nanoparticles and the reduced graphene sheets. The existence of Pt 4f signals (Figure 5a, d) observed for RGO-Pt-7 and RGO-Pt-10 further confirms that the RGO-Pt hybrid materials have been synthesized successfully [44].

Bottom Line: The resultant RGO-Pt hybrid materials were characterized using transmission electron microscopy (TEM), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy, and thermogravimetric analysis.Platinum (Pt) nanoparticles were anchored randomly onto the reduced GO (RGO) sheets with average mean diameters of 1.76 (pH 7) and 1.93 nm (pH 10).The significant Pt diffraction peaks and the decreased intensity of (002) peak in the XRD patterns of RGO-Pt hybrid materials confirmed that the Pt nanoparticles were anchored onto the RGO sheets and intercalated into the stacked RGO layers at these two pH values.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Civil and Environmental Engineering, Nanyang Technological University, 639798, Singapore. JCLiu@ntu.edu.sg.

ABSTRACT
Reduced graphene oxide-nanocrystalline platinum (RGO-Pt) hybrid materials were synthesized by simultaneous co-reduction of graphene oxide (GO) and chloroplatinic acid with sodium citrate in water at 80°C, of pH 7 and 10. The resultant RGO-Pt hybrid materials were characterized using transmission electron microscopy (TEM), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy, and thermogravimetric analysis. Platinum (Pt) nanoparticles were anchored randomly onto the reduced GO (RGO) sheets with average mean diameters of 1.76 (pH 7) and 1.93 nm (pH 10). The significant Pt diffraction peaks and the decreased intensity of (002) peak in the XRD patterns of RGO-Pt hybrid materials confirmed that the Pt nanoparticles were anchored onto the RGO sheets and intercalated into the stacked RGO layers at these two pH values. The Pt loadings for the hybrid materials were determined as 36.83 (pH 7) and 49.18% (pH 10) by mass using XPS analysis. With the assistance of oleylamine, the resultant RGO-Pt hybrid materials were soluble in the nonpolar organic solvents, and the dispersion could remain stable for several months.

No MeSH data available.