scholarly journals Preparation of reduced graphene oxide and its application in chromium-free inorganic insulating coating for oriented silicon steel

2021 ◽  
Vol 2076 (1) ◽  
pp. 012059
Author(s):  
Ying Liu ◽  
Lin Wu ◽  
Ling Tong ◽  
Xiaoyu Yang ◽  
Ao Chen ◽  
...  

Abstract In the fields of military industry, national defence and major engineering, oriented silicon steel is an indispensable material, but the chromium-containing insulating coating coated on its surface is harmful to the environment and humans. Due to poor performance, the industrialization of chromium-free inorganic coating is hindered. To improve the corrosion resistance of chromium-free inorganic insulating coating for oriented silicon steel, reduced graphene oxide (rGO) was prepared by the hydrothermal reduction method and added to the basic chromium-free inorganic insulating coating composed of small-particle silica sol, large-particle silica sol and aluminium dihydrogen phosphate to obtain rGO-containing coating. Scanning electron microscopy (SEM) and Raman spectroscopy were used to analyse the microscopic morphology and structural characteristics of rGO. Electrochemical impedance spectroscopy (EIS) and Tafel polarization curves were used to test the corrosion resistance of the coating. The results show that the prepared rGO has a multi-layer structure with a smaller size than graphene oxide (GO) and can be dispersed in water-based coatings. And rGO can reduce the corrosion current density of the coating by two orders of magnitude, and improve the corrosion resistance of the coating.

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 594 ◽  
Author(s):  
Mara Serrapede ◽  
Marco Fontana ◽  
Arnaud Gigot ◽  
Marco Armandi ◽  
Glenda Biasotto ◽  
...  

A simple, low cost, and “green” method of hydrothermal synthesis, based on the addition of l-ascorbic acid (l-AA) as a reducing agent, is presented in order to obtain reduced graphene oxide (rGO) and hybrid rGO-MoO2 aerogels for the fabrication of supercapacitors. The resulting high degree of chemical reduction of graphene oxide (GO), confirmed by X-Ray Photoelectron Spectroscopy (XPS) analysis, is shown to produce a better electrical double layer (EDL) capacitance, as shown by cyclic voltammetric (CV) measurements. Moreover, a good reduction yield of the carbonaceous 3D-scaffold seems to be achievable even when the precursor of molybdenum oxide is added to the pristine slurry in order to get the hybrid rGO-MoO2 compound. The pseudocapacitance contribution from the resulting embedded MoO2 microstructures, was then studied by means of CV and electrochemical impedance spectroscopy (EIS). The oxidation state of the molybdenum in the MoO2 particles embedded in the rGO aerogel was deeply studied by means of XPS analysis and valuable information on the electrochemical behavior, according to the involved redox reactions, was obtained. Finally, the increased stability of the aerogels prepared with l-AA, after charge-discharge cycling, was demonstrated and confirmed by means of Field Emission Scanning Electron Microscopy (FESEM) characterization.


Chemosensors ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 43
Author(s):  
Esteban Araya-Hermosilla ◽  
Matteo Minichino ◽  
Virgilio Mattoli ◽  
Andrea Pucci

In this work, we investigated the functionalization of reduced graphene oxide (rGO) with 2-(dodecen-1-yl) succinic anhydride (TPSA) to increase the rGO effective interactions with organic solvents both in liquid and vapor phases. Thermogravimetric analysis, STEM, XPS, FTIR-ATR, and Raman spectroscopy confirmed the effective functionalization of rGO with about the 30 wt% of grafted TPSA without affecting the structural characteristics of graphene but successfully enhancing its dispersibility in the selected solvent except for the apolar hexane. Solid TPSA-rGO dispersions displayed a reproducible semiconducting (activated) electrical transport with decreased resistance when heated from 20 °C to 60 °C and with a negative temperature coefficient of 10−3 K−1, i.e., comparable in absolute value with temperature coefficient in metals. It is worth noting that the same solid dispersions showed electrical resistance variation upon exposure to vapors with a detection limit in the order of 10 ppm and sensitivity α of about 10−4 ppm−1.


2020 ◽  
Vol 20 ◽  
pp. 100557
Author(s):  
Ali Abdulkhaleq Alwahib ◽  
Wijdan H. Muttlak ◽  
Bahaa Sami Mahdi ◽  
Ayad Zwayan Mohammed

2019 ◽  
Vol 9 (2) ◽  
pp. 326 ◽  
Author(s):  
Somasekhar Chinnadayyala ◽  
Jinsoo Park ◽  
Yonghyun Choi ◽  
Jae-Hee Han ◽  
Ajay Yagati ◽  
...  

The improved binding ability of graphene–nanoparticle composites to proteins or molecules can be utilized to develop new cell-based assays. In this study, we fabricated reduced graphene oxide–gold nanoparticles (rGO-AuNP) electrodeposited onto a transparent indium tin oxide (ITO) electrode and investigated the feasibility of the electrochemical impedance monitoring of cell growth. The electrodeposition of rGO–AuNP on the ITO was optically and electrochemically characterized in comparison to bare, rGO-, and AuNP-deposited electrodes. The cell growth on the rGO–AuNP/ITO electrode was analyzed via electrochemical impedance measurement together with the microscopic observation of HEK293 cells transfected with a green fluorescent protein expression vector. The results showed that rGO–AuNP was biocompatible and induced an increase in cell adherence to the electrode when compared to the bare, AuNP-, or rGO-deposited ITO electrode. At 54 h cultivation, the average and standard deviation of the saturated normalized impedance magnitude of the rGO–AuNP/ITO electrode was 3.44 ± 0.16, while the value of the bare, AuNP-, and rGO-deposited ITO electrode was 2.48 ± 0.15, 2.61 ± 0.18, and 3.01 ± 0.25, respectively. The higher saturated value of the cell impedance indicates that the impedimetric cell-based assay has a broader measurement range. Thus, the rGO–AuNP/ITO electrode can be utilized for label-free and real-time impedimetric cell-based assays with wider dynamic range.


2020 ◽  
Vol 20 (8) ◽  
pp. 4854-4859 ◽  
Author(s):  
Lei Chen ◽  
Xu Chen ◽  
Yaqiong Wen ◽  
Bixia Wang ◽  
Yangchen Wu ◽  
...  

Nitrogen-enriched reduced graphene oxide electrode material can be successfully prepared through a simple hydrothermal method. The morphology and microstructure of ready to use electrode material is measured by field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). Physical characterizations revealed that nitrogen-enriched reduced graphene oxide electrode material possessed high specific surface area of 429.6 m2 · g−1, resulting in high utilization of electrode materials with electrolyte. Electrochemical performance of nitrogen-enriched reduced graphene oxide electrode was also investigated by cyclic voltammetry (CV), galvanostatic charge/discharge measurements and electrochemical impedance spectroscopy (EIS) in aqueous in 6 M KOH with a three-electrode system, which displayed a high specific capacitance about 223.5 F · g−1 at 1 mV · s−1. More importantly, nitrogenenriched reduced graphene oxide electrode exhibited outstanding stability with 100% coulombic efficiency and with no specific capacitance loss under 2 A · g−1 after 10000 cycles. The supercapacitive behaviors indicated that nitrogen-enriched reduced graphene oxide can be a used as a promising electrode for high-performance super-capacitors.


RSC Advances ◽  
2015 ◽  
Vol 5 (13) ◽  
pp. 9904-9911 ◽  
Author(s):  
Jinsu Kim ◽  
Wai-Hwa Khoh ◽  
Boon-Hong Wee ◽  
Jong-Dal Hong

A rGO/TiO2 free standing film has been fabricated via a simple and facile vacuum filtration system. The composite electrode showed improved electrochemical properties compared to the pure rGO due to the highly expanded layer-structure.


2021 ◽  
pp. 295-308 ◽  
Author(s):  
Jagdish C. Bhangoji ◽  
Srikant Sahoo ◽  
Ashis Kumar Satpati ◽  
Suresh S. Shendage

A simple and environment friendly protocol has been developed for the synthesis of Ag nanoparticles (AgNPs) supported on reduced graphene oxide (rGO) with copper metal foil as reductant. The prepared AgNPs-rGO, nanocomposite was characterized by various analytical techniques such as scanning electron microscopy (SEM), field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD). The electrochemical performance of the material has been evaluated using cyclic voltammetry (CV), chronoamperometry and electrochemical impedance spectroscopy (EIS). The average crystallite size of AgNPs is found to be 32.34 nm. The application of prepared electrocatalyst (AgNPs-rGO) as a non-enzymatic sensor is examined through the modified electrode with the synthesized AgNPs-rGO. The sensor showed excellent performance toward H2O2 reduction with a sensitivity of 12.73 µA.cm-2.mM-1, with a linear dynamic range of 1.5 µM – 100 mM, and the detection limit of 1.90 µM (S/N = 3). Furthermore, the sensor displayed high sensitivity, reproducibility, stability and selectivity for the determination of H2O2. The results demonstrated that AgNPs-rGO has potential applications as sensing material for quantitative determination of H2O2.


2020 ◽  
Vol 20 (5) ◽  
pp. 3148-3156 ◽  
Author(s):  
S. Nehru ◽  
Subramanian Sakthinathan ◽  
P. Tamizhdurai ◽  
Te-Wei Chiu ◽  
K. Shanthi

In the present work, a reduced graphene oxide and multiwalled carbon nanotube (RGO/MWCNTFe3O4) composite decorated with Fe3O4 magnetic nanoparticles was prepared as an electrochemical sensor. The surface morphology of the prepared composite was identified by scanning electron microscopy and X-ray diffraction. The electrochemical properties of the GCE/RGO/MWCNT-Fe3O4 electrode were investigated by electrochemical impedance spectroscopy, cyclic voltammetry and amperometry. The GCE/RGO/MWCNT-Fe3O4 electrode exhibited higher electrocatalytic performance towards the oxidation of hydrazine. In the optimal conditions, the GCE/RGO/MWCNT-Fe3O4 electrode showed a wide linear range (0.15–220 μM), low limit of detection (LOD) (0.75 μM), and high sensitivity (2.868 μA μM−1 cm−2). The prepared GCE/RGO/MWCNT-Fe3O4 electrode also had excellent repeatability, selectivity, and reproducibility. The practical application of the electrode was confirmed with various spiked water samples and demonstrated acceptable recovery.


2019 ◽  
Vol 6 (7) ◽  
pp. 075606 ◽  
Author(s):  
Atefeh Badr ◽  
Mahdieh Sadighi ◽  
Hamed Asgharzadeh ◽  
Taher Rabizadeh

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