scholarly journals One-spot synthesis of FeOOH/rGO composites by ferrous-ion-induced self-assembly of graphene oxides with different degrees of oxidation

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246386
Author(s):  
Yang Hu ◽  
Qingyang Yang ◽  
Yingyu Gu
Keyword(s):  
Graphene Oxide ◽  
Surface Area ◽  
Self Assembly ◽  
Charge Transfer Resistance ◽  
Nano Particles ◽  
Ferrous Ion ◽  
Spot Synthesis ◽  
Graphene Oxides ◽  
Transfer Resistance ◽  
Oxidized Graphite

In this study, graphene oxide sheets with different oxidation degrees were reduced by ferrous ion for coating FeOOH nano particles on reduced graphene oxide (rGO) matrix to synthesize FeOOH/rGO composites. The effect of the degree of oxidation on the morphology and chemical structure of FeOOH/rGO was studied using scanning electron microscopy, Raman spectroscopy, thermogravimetric analysis, and Brunauer-Emmett-Teller surface area analysis. The particle size of FeOOH crystallites was approximately 100 nm, and they were distributed uniformly on the surface and in the pores of FeOOH/rGO. FeOOH/rGO prepared with mildly oxidized graphite had fewer defects, higher specific surface area, and higher FeOOH content than FeOOH/rGO prepared with highly oxidized graphite. These features resulted in better electrochemical properties, such as larger specific capacitance and lower charge transfer resistance.

Inhibitive Performance of 1,4/1,6-Bis(α-Alkyl Pyridinium ) Butane/Hexane Dibromide on A3 Steel

2011 ◽  
Vol 339 ◽  
pp. 96-102
Author(s):  
Xiao Hui Jiang ◽  
Li Mei Zhou ◽  
Shan Zhuo Yao ◽  
Ming Duan ◽  
Xing Qi Hu
Keyword(s):  
Self Assembly ◽  
Gemini Surfactants ◽  
Alkyl Chain ◽  
Charge Transfer Resistance ◽  
Inhibition Rate ◽  
Gravimetric Measurement ◽  
Transfer Resistance ◽  
Alkyl Chains ◽  
Ft Ir ◽  
Positively Charged

1,6-bis(α-alkyl pyridinium ) hexane dibromide was synthesized and confirmed by 1H NMR, 13C NMR, FT-IR and MS. The inhibitive effect of the gemini surfactants for A3 steel in 20% hydrochloric acid was evaluated by gravimetric measurement and electrochemical method. The results indicated that the inhibitive efficiency of the gemini surfactants was affected by the concentration, the length of alkyl chain and spacer in the gemini surfactants. The inhibition rate increased with concentration, the surfactants with four methylenes as spacer showed a slightly better anticorrosive performance than those with six methylenes, and the gemini surfactants with decyl chains exhibited the best inhibitive efficiency. The adsorption of these gemini surfactants on the surface of A3 steel was in accordance with Langmuir isotherm. The electrochemical experiment revealed that the gemini surfactants were mix-type inhibitors. The current density decreased noticeably with the concentration while the charge-transfer resistance increased. The pyridinium rings and positively charged nitrogen atoms in the gemini molecule adsorbed on A3 steel surface and the alkyl chains formed a hydrophobic layer by virtue of self-assembly property of surfactants. Therefore the corrosion of A3 steel was effectively inhibited by the gemini surfactants.

scholarly journals From two-dimensional graphene oxide to three-dimensional honeycomb-like Ni 3 S 2 @graphene oxide composite: insight into structure and electrocatalytic properties

2017 ◽  
Vol 4 (12) ◽  
pp. 171409 ◽  
Author(s):  
Xinting Wei ◽  
Yueqiang Li ◽  
Wenli Xu ◽  
Kaixuan Zhang ◽  
Jie Yin ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Three Dimensional ◽  
Charge Transfer Resistance ◽  
Photoelectrochemical Cells ◽  
One Pot ◽  
Transfer Resistance ◽  
3D Graphene ◽  
Practical Applications ◽  
Oxide Composite ◽  
Solar Water Splitting

Three-dimensional (3D) graphene composites have drawn increasing attention in energy storage/conversion applications due to their unique structures and properties. Herein, we synthesized 3D honeycomb-like Ni 3 S 2 @graphene oxide composite (3D honeycomb-like Ni 3 S 2 @GO) by a one-pot hydrothermal method. We found that positive charges of Ni 2+ and negative charges of NO 3 − in Ni(NO 3 ) 2 induced a transformation of graphene oxide with smooth surface into graphene oxide with wrinkled surface (w-GO). The w-GO in the mixing solution of Ni(NO 3 ) 2 /thioacetamide/H 2 O evolved into 3D honeycomb-like Ni 3 S 2 @GO in solvothermal process. The GO effectively inhibited the aggregation of Ni 3 S 2 nanoparticles. Photoelectrochemical cells based on 3D Ni 3 S 2 @GO synthesized at 60 mM l −1 Ni(NO 3 ) 2 exhibited the best energy conversion efficiency. 3D Ni 3 S 2 @GO had smaller charge transfer resistance and larger exchange current density than pure Ni 3 S 2 for iodine reduction reaction. The cyclic stability of 3D honeycomb-like Ni 3 S 2 @GO was good in the iodine electrolyte. Results are of great interest for fundamental research and practical applications of 3D GO and its composites in solar water-splitting, artificial photoelectrochemical cells, electrocatalysts and Li-S or Na-S batteries.

scholarly journals Structural refinement and electrochemical properties of one dimensional (ZnO NRs)1−x(CNs)x functional hybrids for serotonin sensing studies

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sajid B. Mullani ◽  
Ananta G. Dhodamani ◽  
Annadanesh Shellikeri ◽  
Navaj B. Mullani ◽  
Anita K. Tawade ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Electrochemical Properties ◽  
Surface Area ◽  
Limit Of Detection ◽  
Zno Nanorods ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Bet Analysis ◽  
Lower Charge ◽  
Lower Charge Transfer Resistance

Abstract Herein, the efficient serotonin (5-HT) sensing studies have been conducted using the (ZnO NRs)1−x(CNs)x nanocomposites (NCs) having appropriate structural and electrochemical properties. Initially, the different compositions of ZnO nanorods (NRs), with varying content of carbon nanostructures (CNs=MWCNTs and RGO), are prepared using simple in-situ wet chemical method and thereafter these NCs have been characterized for physico-chemical properties in correlation to the 5-HT sensing activity. XRD Rietveld refinement studies reveal the hexagonal Wurtzite ZnO NRs oriented in (101) direction with space group ‘P63mc’ and both orientation as well as phase of ZnO NRs are also retained in the NCs due to the small content of CNs. The interconnectivity between the ZnO NRs with CNs through different functional moieties is also studied using FTIR analysis; while phases of the constituents are confirmed through Raman analysis. FESEM images of the bare/NCs show hexagonal shaped rods with higher aspect ratio (4.87) to that of others. BET analysis and EIS measurements reveal the higher surface area (97.895 m2/g), lower charge transfer resistance (16.2 kΩ) for the ZCNT 0.1 NCs to that of other NCs or bare material. Thereafter, the prepared NCs are deposited on the screen printed carbon electrode (SPCE) using chitosan as cross-linked agent for 5-HT sensing studies; conducted through cyclic voltammetry (CV) and square wave voltammetry (SWV) measurements. Among the various composites, ZCNT0.1 NCs based electrodes exhibit higher sensing activity towards 5-HT in accordance to its higher surface area, lower particle size and lower charge transfer resistance. SWV measurements provide a wide linear response range (7.5–300 μM); lower limit of detection (0.66 μM), excellent limit of quantification (2.19 μM) and good reproducibility to ZCNT 0.1 NCs as compared to others for 5-HT sensing studies.

scholarly journals Graphene Oxide Coatings Deposited on Steel Substrate Using Electrophoretic Deposition and Electrochemical Evaluation of Coatings in Saline Media

2018 ◽  
Vol 778 ◽  
pp. 111-117 ◽  
Author(s):  
Zaeem Ur Rehman ◽  
Mohsin Ali Raza ◽  
Faizan Ali Ghauri ◽  
Rumasa Kanwal ◽  
Akhlaq Ahmad ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Mild Steel ◽  
Electrophoretic Deposition ◽  
Electrochemical Impedance ◽  
Steel Substrate ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Force Microscopy ◽  
Atomic Force ◽  
Heat Treated

In this study graphene coatings were deposited on mild steel substrate using feasible and environmental friendly method. The successful synthesis of graphite oxide was carried by the modified Hummer’s method. Graphene oxide (GO) coatings were developed from GO/water suspension using electrophoretic deposition (EPD). The EPD parameters voltage and deposition time were varied to deposit uniform adherent coatings. The coatings were post heat treated at 200 °C in vacuum for 4h to assess the effect on coated samples. GO and GO-EPD coating morphology were characterized using Fourier transform infrared spectroscopy (FTIR), Atomic force microscopy (AFM) and Scanning electron microscopy (SEM). Linear polarization (LPR) and electrochemical impedance spectroscopy (EIS) tests were performed in saline solution to evaluate electrochemical response. Coatings were partially reduced due to removal of oxygen containing functional groups during EPD and post heat treatments. The GO post heat treated coating had better corrosion resistance ~2 times than that of bare mild steel and higher charge transfer resistance.

The influence of copper addition on the electrical conductivity and charge transfer resistance of reduced graphene oxide (rGO)

2018 ◽  
Vol 42 (19) ◽  
pp. 16362-16371 ◽  
Author(s):  
Ferry Iskandar ◽  
Oktaviardi Bityasmawan Abdillah ◽  
Erythrina Stavila ◽  
Akfiny Hasdi Aimon
Keyword(s):  
Electrical Conductivity ◽  
Graphene Oxide ◽  
Charge Transfer ◽  
Electrochemical Properties ◽  
Reduced Graphene Oxide ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Copper Addition ◽  
Reduced Graphene

The possible explanations on how the existence of copper, CuO, or Cu2O influences the electrical conductivity and electrochemical properties of rGO.

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