A Study of Graphene Oxidation Using Thermal Analysis-Mass Spectrometry Combined with Pulse Thermal Analysis

Zhang, Heng; 中国科学院上海硅酸盐研究所, 上海 sup>; Yu, Huimei; Xu, Chaohe; Zhang, Minghui; Pan, Xiuhong; Gao, Yanfeng; <, sup> 上海大学材料科学与工程学院, 上海 ,

doi:10.3866/pku.whxb201605111

Cited by 8 publications

(5 citation statements)

References 19 publications

(19 reference statements)

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“…After 500 °C, the burning of the carbon skeleton starts. For all samples, the analysis indicates the existence of a residual mass, in this case of 5.91% [78,79,80].…”

Section: Discussionmentioning

confidence: 99%

Multifunctional Platforms Based on Graphene Oxide and Natural Products

et al. 2019

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Background and objectives: In the last few years, graphene oxide has attracted much attention in biomedical applications due to its unique physico-chemical properties and can be used as a carrier for both hydrophilic and/or hydrophobic biomolecules. The purpose of this paper was to synthesize graphene oxide and to obtain multifunctional platforms based on graphene oxide as a nanocarrier loaded with few biologically active substances with anticancer, antimicrobial or anti-inflammatory properties such as gallic acid, caffeic acid, limonene and nutmeg and cembra pine essential oils. Materials and Methods: Graphene oxide was obtained according to the method developed by Hummers and further loaded with biologically active agents. The obtained platforms were characterized using FTIR, HPLC, TGA, SEM, TEM and Raman spectroscopy. Results: Gallic acid released 80% within 10 days but all the other biologically active agents did not release because their affinity for the graphene oxide support was higher than that of the phosphate buffer solution. SEM characterization showed the formation of nanosheets and a slight increase in the degree of agglomeration of the particles. The ratio I2D/IG for all samples was between 0.18 for GO-cembra pine and 0.27 for GO-limonene, indicating that the GO materials were in the form of multilayers. The individual GO sheets were found to have less than 20 µm, the thickness of GO was estimated to be ~4 nm and an interlayer spacing of about 2.12 Å. Raman spectroscopy indicated that the bioactive substances were adsorbed on the surface and no degradation occurred during loading. Conclusions: These findings encourage this research to further explore, both in vitro and in vivo, the biological activities of bioactive agents for their use in medicine.

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“…After 500 °C, the burning of the carbon skeleton starts. For all samples, the analysis indicates the existence of a residual mass, in this case of 5.91% [78,79,80].…”

Section: Discussionmentioning

confidence: 99%

Multifunctional Platforms Based on Graphene Oxide and Natural Products

et al. 2019

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“…The adsorption of radicals and the decomposition of carbon atoms caused by the reaction with trace oxygen in the carrier gas under high-temperature conditions were related. Zhang et al [38] reported a similar phenomenon of graphene being oxidized at high temperature.…”

Section: Resultsmentioning

confidence: 78%

Effect of long-term ageing on graphene oxide: structure and thermal decomposition

Lü

Yan³

et al. 2021

R. Soc. open sci.

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After long-term ageing, the structure of graphene oxide prepared by the modified Hummers method changed. Because of the desorption of oxygen-containing functional groups, the C/O ratio of graphene oxide increased from 1.96 to 2.76. However, the average interlayer distance decreased from 0.660 to 0.567 nm. The content of -CH- and -CH 2 - decreased; however, the type of oxygen-containing functional groups did not change. Moreover, I D / I G increased from 0.87 to 0.92, indicating that the defect density decreased because of desorbing oxygen functional groups after ageing. When the temperature exceeded 60°C, CO 2 produced by decomposing graphene oxide was detected. The thermal decomposition changed after ageing. The decomposition peak temperature decreased from 216°C to 195°C. The CO 2 amount produced remained almost unchanged; however, the amount of CO, SO 2 and H 2 O decreased. After ageing, the apparent activation energy of graphene oxide decreased from 150 to 134 kJ mol −1 .

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“…As per protocol, the dry specimen was placed in an oven at 70 ± 5 °C for a certain period of time to measure its mass, which could then be compared with the mass of the saturated specimen. However, while GO at room temperature is metastable [ 17 ], it starts to decompose at temperatures between 50 °C and 70 °C [ 18 , 19 ], with accelerated decomposition occurring at temperatures above 100 °C [ 20 ]. Therefore, we adapted the procedure to avoid loss of the coating protective properties, and unacceptable darkening (undesirable for ornamental stones) occurred upon thermal reduction of GO.…”

Section: Methodsmentioning

confidence: 99%

“…to decompose at temperatures between 50 °C and 70 °C [18,19], with accelerated decomposition occurring at temperatures above 100 °C [20]. Therefore, we adapted the procedure to avoid loss of the coating protective properties, and unacceptable darkening (undesirable for ornamental stones) occurred upon thermal reduction of GO.…”

Section: Excess Water Removal After Specimen Immersionmentioning

confidence: 99%

Adaptation of a Standard Method for Water Absorption Testing of Stone Materials: The Case of a Hydrophilic Protective Coating

Búrdalo-Salcedo,

Rodríguez,

Fernández-Raga

et al. 2023

Materials

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The historical stone heritage that we inherit must be passed on to future generations, not only in the same conditions that we found it but, if possible, in better ones. Construction also demands better and more durable materials, often stone. The protection of these materials requires knowledge of the types of rocks and their physical properties. The characterization of these properties is often standardized to ensure the quality and reproducibility of the protocols. These must be approved by entities whose purpose is to improve the quality and competitiveness of companies and to protect the environment. Standardized water absorption tests could be envisaged to test the effectiveness of certain coatings in protecting natural stone against water penetration, but we found that some steps of these protocols neglect any surface modification of the stones, and hence may not be completely effective when a hydrophilic protective coating (i.e., graphene oxide) is present. In this work, we analyze the UNE 13755/2008 standard for water absorption and propose alternative steps to adapt the norm for use with coated stones. The properties of coated stones may invalidate the interpretation of the results if the standard protocol is applied as is, so here we pay special attention to the characteristics of the coating applied, the type of water used for the test, the materials used, and the intrinsic heterogeneity of the specimens.

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A Study of Graphene Oxidation Using Thermal Analysis-Mass Spectrometry Combined with Pulse Thermal Analysis

Cited by 8 publications

References 19 publications

Multifunctional Platforms Based on Graphene Oxide and Natural Products

Multifunctional Platforms Based on Graphene Oxide and Natural Products

Effect of long-term ageing on graphene oxide: structure and thermal decomposition

Adaptation of a Standard Method for Water Absorption Testing of Stone Materials: The Case of a Hydrophilic Protective Coating

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