Reduced graphene oxide/nano-Bioglass composites: processing and super-anion oxide evaluation

RSC Advances ◽  
2016 ◽  
Vol 6 (24) ◽  
pp. 19657-19661 ◽  
Author(s):  
C. Ashok raja ◽  
S. Balakumar ◽  
D. Durgalakshmi ◽  
R. P. George ◽  
B. Anandkumar ◽  
...  

45S5 Bioglass with a mean particle size in the nano regime was synthesized and fabricated with rGO sheets using three different strategies.

CrystEngComm ◽  
2020 ◽  
Vol 22 (27) ◽  
pp. 4580-4590 ◽  
Author(s):  
Zepeng Lv ◽  
Dong Liu ◽  
Weiqian Tian ◽  
Jie Dang

In this study, effectively conductive rGO (reduced graphene oxide) was used as the supporter both to promote charge transfer and to refine particle size of WC, to realize efficient and stable HER performance.


2017 ◽  
Vol 14 (1) ◽  
pp. 19-30 ◽  
Author(s):  
C. H Manoratne ◽  
S. R. D. Rosa ◽  
I. R. M. Kottegoda

Attempts were made to synthesize high quality graphite oxide (GO) and reduced graphene oxide (rGO) by using successive oxidation-reduction process of high quality vein graphite from Sri Lanka. We report the lowest optimum reduction temperature for converting GO to rGO which has been systematically studied using X-ray diffraction spectroscope (XRD) with the high temperature heating attachment (HTA) for the first time. The effect of particle size of graphite on properties of GO and rGO is also compared using commercially available graphite of particle size of ~111 mm and ball-milled graphite of particle size ~37 mm. The GO and rGO were characterized using XRD, UV-Visible spectroscopy, Fourier Transform Infrared spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The GO and rGO synthesized from ball-milled graphite showed higher oxidation and reduction properties as verified through the UV-Vis and FTIR analysis. The SEM analysis revealed that the splitting of graphene layers is efficiently taken place in GO from ball-milled graphite. The lowest optimum temperature for thermal reduction of GO to rGO was found to be at 475 °C. FTIR confirmed the removal of most of the functional groups in rGO and according to the BET surface area analysis few layers, supposed to be 2-6 is formed. The efficient oxidation and reduction process of smaller particle size graphite has led to yield highly oxidized GO and high quality rGO which can be used to prepare high quality graphene for future applications.


2012 ◽  
Vol 14 (37) ◽  
pp. 12794 ◽  
Author(s):  
Sze Yin Chee ◽  
Hwee Ling Poh ◽  
Chun Kiang Chua ◽  
Filip Šaněk ◽  
Zdeněk Sofer ◽  
...  

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1761 ◽  
Author(s):  
Carolina S. Ramirez-Barria ◽  
Diana M. Fernandes ◽  
Cristina Freire ◽  
Elvira Villaro-Abalos ◽  
Antonio Guerrero-Ruiz ◽  
...  

N-doped (NrGO) and non-doped (rGO) graphenic materials are prepared by oxidation and further thermal treatment under ammonia and inert atmospheres, respectively, of natural graphites of different particle sizes. An extensive characterization of graphene materials points out that the physical properties of synthesized materials, as well as the nitrogen species introduced, depend on the particle size of the starting graphite, the reduction atmospheres, and the temperature conditions used during the exfoliation treatment. These findings indicate that it is possible to tailor properties of non-doped and N-doped reduced graphene oxide, such as the number of layers, surface area, and nitrogen content, by using a simple strategy based on selecting adequate graphite sizes and convenient experimental conditions during thermal exfoliation. Additionally, the graphenic materials are successfully applied as electrocatalysts for the demanding oxygen reduction reaction (ORR). Nitrogen doping together with the starting graphite of smaller particle size (NrGO325-4) resulted in a more efficient ORR electrocatalyst with more positive onset potentials (Eonset = 0.82 V versus RHE), superior diffusion-limiting current density (jL, 0.26V, 1600rpm = −4.05 mA cm−2), and selectivity to the direct four-electron pathway. Moreover, all NrGOm-4 show high tolerance to methanol poisoning in comparison with the state-of-the-art ORR electrocatalyst Pt/C and good stability.


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