The production of graphene oxide with less acid is beneficial to reduce the costs and lower the impact on the environment,but it is still a great challenge.In this work,a relatively simple,safe method for synthesizing...The production of graphene oxide with less acid is beneficial to reduce the costs and lower the impact on the environment,but it is still a great challenge.In this work,a relatively simple,safe method for synthesizing graphene oxide with much less acid(decrease∼40%)is proposed.With assistance of the heat absorbed from environment and reaction system,the temperature of reaction system of low acid can be well controlled.More interestingly,the graphite can be completely oxidized into graphite oxide by using much less acid,with lowering the production of high-concentration aqueous waste acid(>1 mol/L,decrease∼40%).A series of characterizations show that the prepared graphene oxide has similar yield and functional groups compared with that of using the conventional method.This work provides a safe and environmentally friendly choice for the large-scale production of graphene oxide and its derivative materials.展开更多
Graphene oxide was synthesized from graphite flakes using modified Hummers’method.The interlayer spacings of graphite,graphite oxide and graphene oxide were measured using X-ray diffraction technique.The C/O atomic r...Graphene oxide was synthesized from graphite flakes using modified Hummers’method.The interlayer spacings of graphite,graphite oxide and graphene oxide were measured using X-ray diffraction technique.The C/O atomic ratios of graphite oxide and graphene oxide were calculated from XPS measurements.The transformation of graphite to graphite oxide and finally to graphene oxide was clearly observed from the micro-Raman spectroscopy data and was confirmed from the FESEM micrographs.UV-VIS-NIR spectrophotometer was used to study the absorbance of graphene oxide and reduced graphene oxide samples.Finally,the chemically reduced graphene oxide was heat-treated in air to obtain chemically modified graphene.展开更多
Chemical oxidation is used to cut and unzip multi-walled carbon nanotubes in the transverse direction and the axial direction to form graphene oxide nanoribbon （GONR）. Ruthenium oxide/reduced graphene oxide nanoribb...Chemical oxidation is used to cut and unzip multi-walled carbon nanotubes in the transverse direction and the axial direction to form graphene oxide nanoribbon （GONR）. Ruthenium oxide/reduced graphene oxide nanoribbon composite （RuO2/rGONR） with a 72.5 wt% RuO2 loading is synthesized through an aqueous-phase reaction, in which GONR is served as starting material, followed by mild thermal treatment in ambient air. The resulting RuO2/rGONR composite achieves specific capacitance up to 677 F.g l at the current density of 1 A·g^-1 in three-electrode system using 1 mol·L^-1 H2SO4 as electrolyte. The resultant electrode exhibits an excellent rate capability （91.8% retention rate at 20 A·g^-1）. Especially, the symmetric supercapacitor assembled on the basis of RuO2/rGONR electrode delivers high energy density （16.2 Wh·kg^-1） even at the power density of 9885 W·kg^-1, which is very essential for supercapacitors.展开更多
基金the Guangzhou Municipal Science and Technology Bureau(Nos.202002030368,202102080408)for financial support.
文摘The production of graphene oxide with less acid is beneficial to reduce the costs and lower the impact on the environment,but it is still a great challenge.In this work,a relatively simple,safe method for synthesizing graphene oxide with much less acid(decrease∼40%)is proposed.With assistance of the heat absorbed from environment and reaction system,the temperature of reaction system of low acid can be well controlled.More interestingly,the graphite can be completely oxidized into graphite oxide by using much less acid,with lowering the production of high-concentration aqueous waste acid(>1 mol/L,decrease∼40%).A series of characterizations show that the prepared graphene oxide has similar yield and functional groups compared with that of using the conventional method.This work provides a safe and environmentally friendly choice for the large-scale production of graphene oxide and its derivative materials.
文摘Graphene oxide was synthesized from graphite flakes using modified Hummers’method.The interlayer spacings of graphite,graphite oxide and graphene oxide were measured using X-ray diffraction technique.The C/O atomic ratios of graphite oxide and graphene oxide were calculated from XPS measurements.The transformation of graphite to graphite oxide and finally to graphene oxide was clearly observed from the micro-Raman spectroscopy data and was confirmed from the FESEM micrographs.UV-VIS-NIR spectrophotometer was used to study the absorbance of graphene oxide and reduced graphene oxide samples.Finally,the chemically reduced graphene oxide was heat-treated in air to obtain chemically modified graphene.
基金Acknowledgement We gratefully acknowledge the financial support offered by the National Natural Science Foundation of China （Nos. 20963009 21163017 and 21563027） and Specialized Research Fund for the Doctoral Program of Higher Education（No. 20126203110001）.
文摘Chemical oxidation is used to cut and unzip multi-walled carbon nanotubes in the transverse direction and the axial direction to form graphene oxide nanoribbon （GONR）. Ruthenium oxide/reduced graphene oxide nanoribbon composite （RuO2/rGONR） with a 72.5 wt% RuO2 loading is synthesized through an aqueous-phase reaction, in which GONR is served as starting material, followed by mild thermal treatment in ambient air. The resulting RuO2/rGONR composite achieves specific capacitance up to 677 F.g l at the current density of 1 A·g^-1 in three-electrode system using 1 mol·L^-1 H2SO4 as electrolyte. The resultant electrode exhibits an excellent rate capability （91.8% retention rate at 20 A·g^-1）. Especially, the symmetric supercapacitor assembled on the basis of RuO2/rGONR electrode delivers high energy density （16.2 Wh·kg^-1） even at the power density of 9885 W·kg^-1, which is very essential for supercapacitors.
