Hydrothermally reduced Graphene Oxide coated Carbon Cloth for Flexible Supercapacitors

Author(s):  
Subhakaran Singh Rajaputra ◽  
Nagalakshmi P ◽  
Anjaneyulu Yerramilli ◽  
Naga Mahesh K

Abstract Hydrothermally synthesized Graphene (HRG) was tested for its supercapacitive behavior using nickel (Ni) and hydrothermally treated carbon cloth as current collectors, respectively. Performance evaluation studies were carried out in an in-house fabricated SS cell. Commercially obtained untreated carbon cloth (CCUn) was exfoliated via oxidation (CCOx) followed by hydrothermal treatment to obtain a reduced carbon cloth (CCHy). The Physico-chemical and electrochemical properties of carbon cloth by oxidative exfoliation and hydrothermal treatment have been studied using SEM, XRD, FTIR, BET surface area, Contact angle measurements, cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and EIS. HRG coated on the CCHy (HRG-CCHy) had shown superior performance and endurance compared to HRG coated on Ni strip (HRG-Ni), with distinguishable specific capacitances (Cs) of 170 and 134 F g-1 at 0.5 A g-1 current density, respectively. At a higher 10 A g-1 current density, HRG-CCHy, and HRG-Ni have displayed distinctive specific capacitances of 120 and 80 F g-1, respectively, indicating a comparative decline in the performance of HRG-Ni with respect to HRG-CCHy. Endurance study performed for 5000 cycles at 2 A g-1, resulted in HRG-CCHy and HRG-Ni, retaining 88% and 81% of their initial specific capacitances. At 1 kW kg-1 of power density, HRG-CCHy displayed a 5.5 Wh kg-1 of energy density. The electrochemical performance of HRG-CCHy may be attributed to exceptional properties like high wettability, low impedance, high pore volume, and specific surface area.

2014 ◽  
Vol 699 ◽  
pp. 1006-1011
Author(s):  
Nurul’ Ain binti Jamion ◽  
Siti Mazleena binti Mohamed

Interface adsorption of gases and liquid on a clean solid surface could be due to the physical or chemical adsorption. In this study, the activated carbon was prepared from sugar cane husk (powder and granular form) using phosphoric acid (H3PO4) as activating agent. Sample was activated at 500°C for two hours in the furnace and washed using vacuum method. Besides, surface area of activated carbon was defined using Single Point Brunauer-Emmett-Teller (BET) Nitrogen Gas. The physico-chemical characteristics of the prepared activated carbon were characterized by Fourier-Transformed Infrared Spectroscopy (FTIR), gravimetric method, and Field Emission Scanning Electron Microscopy (FESEM). The adsorption study by surfactants, namely CTAB (cationic) and TX-100 (non-ionic) were investigated. The experimental results showed that a good activated carbon was prepared from sugar cane husk granular (SCH-G) gave the highest BET surface area of 860.18 m2/g and the adsorption capacity of SCH-G activated carbon at 25°C using TX-100 (205.81 mg g-1) was greater compared to the CTAB (108.20 mg g-1). This study has shown that the sugar cane husk was a good activated carbon and has potential to be used as adsorbent for the removal of surfactants from aqueous solutions.


2021 ◽  
pp. X
Author(s):  
Shih-Hang CHANG ◽  
Yuan-Ting TSAO ◽  
Kuan-Wei TUNG

In this study, we investigate the effect of heat treatment on the surface properties of carbon cloth electrodes and on the power generation efficiencies of microbial fuel cells (MFCs) configured with the heat-treated carbon cloth electrodes. Water contact angle measurements show that the hydrophobic surfaces of the carbon cloth became super-hydrophilic after heat treatment at a temperature above 500 °C, making it suitable for bacterial propagation. X-ray photoelectron spectrometry revealed that the signal of the C-O functional group of the carbon cloth electrodes increased in intensity after heat treatment. The MFCs configured with heat-treated carbon cloth electrode exhibited high power density of 16.58 mW/m2, whereas that of the untreated MFCs was only 8.86 mW m2. Compared with other chemical modifications, heat treatment does not use any environmentally unsound acidic or toxic solutions during modification and are promising for manufacturing large-scale MFC stacks.


2015 ◽  
Vol 15 (3) ◽  
pp. 649-655 ◽  
Author(s):  
Husam Faiz Haddad ◽  
Azhagapillai Prabhu ◽  
Ahmed Al Shoaibi ◽  
Chandrasekar Srinivasakannan

The adsorption of benzene, toluene and xylene (BTX) was investigated covering different types of commercially available activated carbons with varied surface area and surface functional groups. The physico-chemical properties were characterized by Brunauer–Emmett–Teller (BET) surface area analysis, Fourier transform infrared (FTIR) spectroscopy and the Boehm titration method. Experiments to assess the adsorption isotherms and kinetics of adsorption were performed and the results are presented. An increase in the surface acid functional groups was found to decrease the adsorption capacity, with the highest adsorption capacity corresponding to carbon with lowest acid functionality.


2020 ◽  
Vol 32 (4) ◽  
pp. 810-814
Author(s):  
Darma Santi ◽  
Triyono ◽  
Wega Trisunaryanti ◽  
Iip Izul Falah

Zinc(II) chloride, as an activating agent and H2O2 as an oxidizing agent, prepared the hydrothermal treatment synthesis of porous carbon (HC). The hydrothermal followed by carbonization and then by oxidation at 350 °C under oxygen stream (HC-Ox). All the products characterized by XRD, FT-IR, amount of oxygenated functional groups (OFGs) obtained by the Boehm method, the total acid amount by NH3 base vapour adsorption, surface area analyzer (SAA) and SEM. The XRD results showed that all of the carbonized samples were amorphous, which characteristic for porous carbonized. The results of FT-IR and Boehm titration revealed that the phenolic group was the highest contributor to OFGs on HC-Ox samples (7.095 meq/g) and carboxylic groups of 2.685 meq/g. The maximum BET surface area was found to be 443.5 (m2/g) for C-Ox and 232.2 (m2/g) for HC-Ox. The SEM image displayed that the morphology of the HC samples was a stacking honeycomb-like structure.


Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4546
Author(s):  
Kuan-Ching Lee ◽  
Mitchell Shyan Wei Lim ◽  
Zhong-Yun Hong ◽  
Siewhui Chong ◽  
Timm Joyce Tiong ◽  
...  

Coconut shells, low-cost and renewable agro-wastes, were used as a starting material in the synthesis of hierarchical activated carbons via hydrothermal, KOH-activation, and carbonization techniques. The ratio of KOH to hydrochar was varied in a systemic manner to study how it influences the texture and electrochemical behavior of the capacitor. Coconut shell-based carbon coated on nickel foams presented a surface area of 1567 m2 g−1, with micropores as well as mesopores widely distributed. The sample showed superior electrochemical performance, attaining 449 F g−1 at 1 A g−1 in 6 M LiNO3 aqueous solution. The solid-state symmetric supercapacitor device delivered a specific capacitance of 88 F g−1 at 1 A g−1 and a high energy density of 48.9 Whkg−1 at a power density of 1 kW kg−1. At a wide voltage window of 2.0 V, the sample was highly stable during the cycle test, showing a 92% capacitance retention at 2 A g−1 after cycling for 5000 times. The superior performance is due to the sample possessing great BET surface area, a good distribution of pores, and the usage of a suitable electrolyte. This facilitates an electrical double layer that can be deployed for applications to store energy.


2013 ◽  
Vol 594-595 ◽  
pp. 49-56
Author(s):  
Nurul Aini Edama ◽  
Alawi Sulaiman ◽  
Ku Halim Ku Hamid ◽  
Miradatul Najwa Mohd Rodhi ◽  
Musa Mohibah ◽  
...  

The effects of hydrochloric acid (HCL) modification of the surface area, morphology and physico-chemical properties of Sayong kaolinite clay was investigated in this study. Sayong kaolinite clay was refluxed with different concentration of HCL (1M, 5M and 10M) at 100 °C for 4 hours and followed by calcination at 500 °C at 1 hour. The samples of untreated and treated clay were characterized by different analytical equipment such as BET Surface Area Analyzer, X-Ray Fluorescence (XRF), Fourier Transform Infrared (FTIR), Thermogravimetric Analyzer (TGA) and Field Emission Scanning Electron Microscopy (FESEM). The acid treatment increased the surface area of the Sayong kaolinite clay almost three times from 24.46 m2/g to the maximum value which is 64.04 m2/g once treated with 5M HCL. The increasing of the surface area is due to the formation of amorphous silica phase and removal of the octahedral Al3+cations and other impurities (such as Mg2+, K+, Ca+etc.) when the acid strength is increasing as reported in XRF analysis. FTIR study shows the change of the peak intensity of several types of structural OH groups that presently in the untreated and acid treated samples. TGA-DTA profiles shows that acid treatment increased the amount of physisorbed water as the acid concentration is increased. There are three of endothermic peaks was observed in the untreated sample which centered at 49 °C, 275 °C and 520 °C. However, when the clay samples treated with acid, it has increased the physisorbed water and decreased the structural and coordinated water which caused the change in the endothermic curves in the treated sample.


In this paper, easy, rapid and cheap synthetic method was described for florfenicol-silver nanocomposite by sonochemical method. Florfenicol-silver nanocomposite was characterized based on three classes namely index, identification and morphology class. Index characterization was carried out by zeta sizing, BET surface area and zeta potential. Identification characterization was performed using X-ray diffraction (XRD) and Raman spectrometry. Morphology characterization was done utilizing transmission electron microscope (TEM), scanning electron microscope (SEM) and atomic force microscope (AFM). Characterization results showed zeta sizing of florfenicol was 30.44nm, while florfenicol-silver nanocomposite was 33.5 nm with zeta potential -14.1 and -18, respectively. BET surface area was found to be 13.3, 73.2 and 103.69 m2/g for florfenicol, silver nanoparticles and florfenicol-silver nanocomposite respectively. XRD and Raman charts confirmed the formation of florfenicol-silver nanocomposite without any contamination. TEM, SEM and AFM spectral data illustrated spherical to sub spherical shape of silver nanoparticles on cubic to sheet shape of florfenicol with size less than 50 nm. Antimicrobial activity was screened where the average zone of inhibitions caused by the prepared nanocomposite were 28.3 mm, 24 mm, 27.3 mm and 24 mm compared to 17.7 mm, 16 mm, 18.7 mm and 13.3 mm of the native drug and 13 mm, 10 mm, 14.3 mm and 15 mm of the used positive reference standards against E. coli, Salmonella typhymurium, Staphylococcus aureus and Staph.aureus MRSA respectively.


Author(s):  
Reza Yazdanpanah ◽  
Eshagh Moradiyan ◽  
Rouein Halladj ◽  
Sima Askari

Aim and Objective: The research focuses on recent progress in the production of light olefins. Hence, the common catalyst of the reaction (SAPO-34) deactivates quickly because of coke formation, we reorganized the mechanism combining SAPO-34 with a natural zeolite in order to delay the deactivation time. Materials and Methods: The synthesis of nanocomposite catalyst was conducted hydrothermally using experimental design. Firstly, Clinoptilolite was modified using nitric acid in order to achieve nano scaled material. Then, the initial gel of the SAPO-34 was prepared using DEA, aluminum isopropoxide, phosphoric acid and TEOS as the organic template, sources of Aluminum, Phosphor, and Silicate, respectively. Finally, the modified zeolite was combined with SAPO-34's gel. Results: 20 different catalysts due to D-Optimal design were synthesized and the nanocomposite with 50 weight percent of SAPO-34, 4 hours Crystallization and early Clinoptilolite precipitation showed the highest relative crystallinity, partly high BET surface area and hierarchical structure. Conclusion: Different analysis illustrated the existence of both components. The most important property alteration of nanocomposite was the increment of pore mean diameters and reduction in pore volumes in comparison with free SAPO-34. Due to low price of Clinoptilolite, the new catalyst develops the economy of the process. Using this composite, according to formation of multi-sized pores located hierarchically on the surface of the catalyst and increased surface area, significant amounts of Ethylene and Propylene, in comparison with free SAPO-34, were produced, as well as deactivation time that was improved.


Nanoscale ◽  
2015 ◽  
Vol 7 (25) ◽  
pp. 10974-10981 ◽  
Author(s):  
Xiulin Yang ◽  
Ang-Yu Lu ◽  
Yihan Zhu ◽  
Shixiong Min ◽  
Mohamed Nejib Hedhili ◽  
...  

High surface area FeP nanosheets on a carbon cloth were prepared by gas phase phosphidation of electroplated FeOOH, which exhibit exceptionally high catalytic efficiency and stability for hydrogen generation.


Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1238
Author(s):  
Garven M. Huntley ◽  
Rudy L. Luck ◽  
Michael E. Mullins ◽  
Nick K. Newberry

Four naturally occurring zeolites were examined to verify their assignments as chabazites AZLB-Ca and AZLB-Na (Bowie, Arizona) and clinoptilolites NM-Ca (Winston, New Mexico) and NV-Na (Ash Meadows, Nevada). Based on powder X-ray diffraction, NM-Ca was discovered to be mostly quartz with some clinoptilolite residues. Treatment with concentrated HCl (12.1 M) acid resulted in AZLB-Ca and AZLB-Na, the chabazite-like species, becoming amorphous, as confirmed by powder X-ray diffraction. In contrast, NM-Ca and NV-Na, which are clinoptilolite-like species, withstood boiling in concentrated HCl acid. This treatment removes calcium, magnesium, sodium, potassium, aluminum, and iron atoms or ions from the framework while leaving the silicon framework intact as confirmed via X-ray fluorescence and diffraction. SEM images on calcined and HCl treated NV-Na were obtained. BET surface area analysis confirmed an increase in surface area for the two zeolites after treatment, NM-Ca 20.0(1) to 111(4) m2/g and NV-Na 19.0(4) to 158(7) m2/g. 29Si and 27Al MAS NMR were performed on the natural and treated NV-Na zeolite, and the data for the natural NV-Na zeolite suggested a Si:Al ratio of 4.33 similar to that determined by X-Ray fluorescence of 4.55. Removal of lead ions from solution decreased from the native NM-Ca, 0.27(14), NV-Na, 1.50(17) meq/g compared to the modified zeolites, 30 min HCl treated NM-Ca 0.06(9) and NV-Na, 0.41(23) meq/g, and also decreased upon K+ ion pretreatment in the HCl modified zeolites.


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