scholarly journals Pseudocapacitive Effect of Carbons Doped with Different Functional Groups as Electrode Materials for Electrochemical Capacitors

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5577
Author(s):  
Mojtaba Mirzaeian ◽  
Qaisar Abbas ◽  
Michael. R. C. Hunt ◽  
Peter Hall
Keyword(s):  
Activated Carbon ◽  
Photoelectron Spectroscopy ◽  
Nitrogen Doping ◽  
Electrode Materials ◽  
Carbon Matrix ◽  
Fold Increase ◽  
Xrd Analysis ◽  
Carbon Aerogels ◽  
Nitrogen Doped ◽  
Bet Analysis

In this study, RF-based un-doped and nitrogen-doped aerogels were produced by polymerisation reaction between resorcinol and formaldehyde with sodium carbonate as catalyst and melamine as the nitrogen source. Carbon/activated carbon aerogels were obtained by carbonisation of the gels under inert atmosphere (Ar) followed by activation of the carbons under CO2 at 800 °C. The BET analysis of the samples showed a more than two-fold increase in the specific Surf. area and pore volume of carbon from 537 to 1333 m2g−1 and 0.242 to 0.671 cm3g−1 respectively after nitrogen doping and activation. SEM and XRD analysis of the samples revealed highly porous amorphous nanostructures with denser inter-particle cross-linked pathways for the activated nitrogen-doped carbon. The X-Ray Photoelectron Spectroscopy (XPS) results confirmed the presence of nitrogen and oxygen heteroatoms on the Surf. and within the carbon matrix where improvement in wettability with the drop in the contact angle from 123° to 80° was witnessed after oxygen and nitrogen doping. A steady drop in the equivalent series (RS) and charge transfer (RCT) resistances was observed by electrochemical measurements after the introduction of nitrogen and oxygen heteroatoms. The highest specific capacitance of 289 Fg−1 with the lowest values of 0.11 Ω and 0.02 Ω for RS and RCT was achieved for nitrogen and oxygen dual-doped activated carbon in line with its improved Surf. chemistry and wettability, and its enhanced conductivity due to denser inter-particle cross-linked pathways.

scholarly journals Modified Activation Process for Supercapacitor Electrode Materials from African Maize Cob

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5412
Author(s):  
Moses Kigozi ◽  
Ravi Kali ◽  
Abdulhakeem Bello ◽  
Balaji Padya ◽  
Godwin Mong Kalu-Uka ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Photoelectron Spectroscopy ◽  
Electrode Materials ◽  
Chemical Activation ◽  
Mesoporous Structure ◽  
Activation Process ◽  
Energy Storage Devices ◽  
Supercapacitor Electrode ◽  
X Ray ◽  
Bet Analysis

In this work, African maize cobs (AMC) were used as a rich biomass precursor to synthesize carbon material through a chemical activation process for application in electrochemical energy storage devices. The carbonization and activation were carried out with concentrated Sulphuric acid at three different temperatures of 600, 700 and 800 °C, respectively. The activated carbon exhibited excellent microporous and mesoporous structure with a specific surface area that ranges between 30 and 254 m2·g−1 as measured by BET analysis. The morphology and structure of the produced materials are analyzed through Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Boehm titration, X-ray Photoelectron Spectroscopy (XPS) and Raman Spectroscopy. X-ray photoelectron spectroscopy indicates that a considerable amount of oxygen is present in the materials. The functional groups in the activated carbon enhanced the electrochemical performance and improved the material’s double-layer capacitance. The carbonized composite activated at 700 °C exhibited excellent capacitance of 456 F g−1 at a specific current of 0.25 A g−1 in 6 M KOH electrolyte and showed excellent stability after 10,000 cycles. Besides being a low cost, the produced materials offer good stability and electrochemical properties, making them suitable for supercapacitor applications.

Fabrication of nitrogen-doped hierarchical porous carbons from Sargassum as advanced electrode materials for supercapacitors

2021 ◽  
Author(s):  
Feiqiang Guo ◽  
Yinbo Zhan ◽  
Xiaopeng Jia ◽  
Huiming Zhou ◽  
Shuang Liang ◽  
...  
Keyword(s):  
High Performance ◽  
Nitrogen Doping ◽  
Electrode Materials ◽  
Three Dimensional ◽  
Koh Activation ◽  
Porous Carbons ◽  
Nitrogen Doped ◽  
Novel Approach ◽  
Hierarchical Porous ◽  
Hierarchical Porous Carbons

Using Sargassum as the precursor, a novel approach was developed to synthesize three-dimensional porous carbons as high-performance electrode materials for supercapacitors via KOH activation and subsequent nitrogen-doping employing melamine as...

Field emission properties of nitrogen-doped diamond-like carbon films deposited by direct metal ion beam deposition

2001 ◽  
Vol 697 ◽  
Author(s):  
Kie Moon Song ◽  
Namwoong Paik ◽  
Steven Kim ◽  
Daeil Kim ◽  
Seongjin Kim ◽  
...  
Keyword(s):  
Field Emission ◽  
Photoelectron Spectroscopy ◽  
Metal Ion ◽  
Nitrogen Doping ◽  
Ion Beam ◽  
Diamond Like Carbon ◽  
Emission Data ◽  
Nitrogen Doped ◽  
Ion Beam Deposition ◽  
Beam Deposition

AbstractNitrogen-doped diamond-like carbon (DLC) films were deposited on a silicon substrate by direct metal ion beam deposition (DMIBD). Partial pressures of nitrogen gas were changed to get different compositions of nitrogen in the DLC films. The composition and surface morphology of the films were examined using X-ray photoelectron spectroscopy (XPS) and atomic force microscope (AFM). Effect of nitrogen doping on field emission property was studied. The field emission data indicated that the nitrogen doping lowered the turn-on field and increase the current density. It was believed that doping of nitrogen into the DLC film plays an important role in enhancement of the field emission. This enhancement of field emission could be explained by the improvement of electron transport through nitrogen-dope DLC layer.

Porous nitrogen-doped hollow carbon spheres derived from polyaniline for high performance supercapacitors

2014 ◽  
Vol 2 (15) ◽  
pp. 5352-5357 ◽  
Author(s):  
Jinpeng Han ◽  
Guiyin Xu ◽  
Bing Ding ◽  
Jin Pan ◽  
Hui Dou ◽  
...  
Keyword(s):  
Porous Structure ◽  
High Performance ◽  
Nitrogen Doping ◽  
Electrode Materials ◽  
Carbon Spheres ◽  
Hierarchical Porous Structure ◽  
Nitrogen Doped ◽  
Hierarchical Porous ◽  
Hollow Carbon ◽  
Hollow Carbon Spheres

The porous nitrogen-doped hollow carbon spheres derived from polyaniline are promising electrode materials for high performance supercapacitors due to their hierarchical porous structure and nitrogen-doping.

Preparation and performance of nitrogen-doped carbon aerogels as electrode materials

2012 ◽  
Vol 24 (12) ◽  
pp. 2848-2852
Author(s):  
刘西川 Liu Xichuan ◽  
袁磊 Yuan Lei ◽  
冯灏 Feng Hao ◽  
付志兵 Fu Zhibing ◽  
王朝阳 Wang Chaoyang ◽  
...  
Keyword(s):  
Electrode Materials ◽  
Carbon Aerogels ◽  
Nitrogen Doped ◽  
And Performance ◽  
Nitrogen Doped Carbon

scholarly journals Catalytic Performance of Nitrogen-Doped Activated Carbon Supported Pd Catalyst for Hydrodechlorination of 2,4-Dichlorophenol or Chloropentafluoroethane

Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 674 ◽  
Author(s):  
Haodong Tang ◽  
Bin Xu ◽  
Meng Xiang ◽  
Xinxin Chen ◽  
Yao Wang ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Liquid Phase ◽  
Gas Phase ◽  
Nitrogen Doping ◽  
Catalyst Surface ◽  
Catalytic Performance ◽  
Atomic Ratio ◽  
Pd Catalyst ◽  
Nitrogen Doped ◽  
The Stability

Nitrogen-doped activated carbon (N-AC) obtained through the thermal treatment of a mixture of HNO3-pretreated activated carbon (AC) and urea under N2 atmosphere at 600 °C was used as the carrier of Pd catalyst for both liquid-phase hydrodechlorination of 2,4-dichlorophenol (2,4-DCP) and gas-phase hydrodechlorination of chloropentafluoroethane (R-115). The effects of nitrogen doping on the dispersion and stability of Pd, atomic ratio of Pd/Pd2+ on the surface of the catalyzer, the catalyst’s hydrodechlorination activity, as well as the stability of N species in two different reaction systems were investigated. Our results suggest that, despite no improvement in the dispersion of Pd, nitrogen doping may significantly raise the atomic ratio of Pd/Pd2+ on the catalyst surface, with a value of 1.2 on Pd/AC but 2.2 on Pd/N-AC. Three types of N species, namely graphitic, pyridinic, and pyrrolic nitrogen, were observed on the surface of Pd/N-AC, and graphitic nitrogen was stable in both liquid-phase hydrodechlorination of 2,4-DCP and gas-phase hydrodechlorination of R-115, with pyridinic and pyrrolic nitrogen being unstable during gas-phase hydrodechlorination of R-115. As a result, the average size of Pd nanocrystals on Pd/N-AC was almost kept unchanged after liquid-phase hydrodechlorination of 2,4-DCP, whereas crystal growth of Pd was clearly observed on Pd/N-AC after gas-phase hydrodechlorination of R-115. The activity test revealed that Pd/N-AC exhibited a much better performance than Pd/AC in liquid-phase hydrodechlorination of 2,4-DCP, probably due to the enhanced stability of Pd exposed to the environment resulting from nitrogen doping as suggested by the higher atomic ratio of Pd/Pd2+ on the catalyst surface. In the gas-phase hydrodechlorination of R-115, however, a more rapid deactivation phenomenon occurred on Pd/N-AC than on Pd/AC despite a higher activity initially observed on Pd/N-AC, hinting that the stability of pyridinic and pyrrolic nitrogen plays an important role in the determination of catalytic performance of Pd/N-AC.

scholarly journals Preparation and Photocatalytic Performances of WO3/TiO2 Composite Nanofibers

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Xiuping Han ◽  
Binghua Yao ◽  
Keying Li ◽  
Wenjing Zhu ◽  
Xuyuan Zhang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Photocatalytic Oxidation ◽  
Composite Nanofibers ◽  
Photogenerated Electron ◽  
Xrd Analysis ◽  
Catalytic Performance ◽  
Active Species ◽  
X Ray ◽  
Bet Analysis ◽  
Electron Holes

The use of sunlight for photocatalytic oxidation is an ideal strategy, but it is limited by factors such as insufficient light absorption intensity of the photocatalyst and easy recombination of photogenerated electron holes. TiO2 is favored by researchers as an environment-friendly catalyst. In this paper, TiO2 is combined with WO3 to obtain a nanofiber with excellent catalytic performance under sunlight. The WO3/TiO2 composite nanofibers were synthesized by using the electrospinning method. The X-ray diffraction (XRD) analysis indicated that WO3 was successfully integrated onto the surface of TiO2. The photodegradation performance and photocurrent analysis of the prepared nanofibers showed that the addition of WO3 really improved the photocatalytic performance of TiO2 nanofibers, methylene blue (MB) degradation rate increased from 72% to 96%, and 5% was the optimal composite mole percentage of W to Ti. The scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectra (UV-Vis DRS), and Brunauer-Emmett-Teller (BET) analysis further characterized the properties of 5% WO3/TiO2 nanofibers. The H2 generation rate of 5% WO3/TiO2 nanofibers was 107.15 μmol·g−1·h−1, in comparison with that of TiO2 nanofibers (73.21 μmol·g−1·h−1) under the same condition. The 5% WO3/TiO2 produced ·OH under illumination, which played an important role in the MB degradation. Also, the enhanced photocatalytic mechanism was also proposed based on the detailed analysis of the band gap and the active species trapping experiment. The results indicated that the effective separation of Z-scheme photogenerated electron-hole pairs and transfer system constructed between TiO2 and WO3 endowed the excellent photocatalytic activity of 5% WO3/TiO2 nanofibers.

scholarly journals Activated carbons for the removal of heavy metal ions: A systematic review of recent literature focused on lead and arsenic ions

2015 ◽  
Vol 13 (1) ◽  
Author(s):  
Eleni A. Deliyanni ◽  
George Z. Kyzas ◽  
Kostas S. Triantafyllidis ◽  
Kostas A. Matis
Keyword(s):  
Systematic Review ◽  
Activated Carbon ◽  
Photoelectron Spectroscopy ◽  
Activated Carbons ◽  
Thermal Analyses ◽  
High Surface ◽  
High Surface Area ◽  
Adsorption Removal ◽  
Bet Analysis ◽  
Removal Of Heavy Metals

AbstractThis work is a systematic review of the literature over the past decade of the application of activated carbon (microporous or mesoporous) as adsorbents for the removal of heavy metals, focusing especially on lead (Pb) and arsenic (As) ions from the aqueous phase. Classical examples from our lab are also given. Activated carbon is known to provide a high surface area for adsorption. Generally, surface modification is typically required, such as oxidation, treatment with ammonia or even impregnation with ferric ion, etc. and the adsorbent material may originate from various sources. The pristine materials, after modification and those after batch-wise adsorption, were characterized by available techniques (BET analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, thermal analyses, X-ray photoelectron spectroscopy). Adsorption isotherms, thermodynamics and kinetics of the process are also discussed. Selected studies from the literature are examined in comparison with other adsorbents. The role of chemistry in the metals adsorption/removal was investigated.

scholarly journals Effect of Nitrogen Doping on the Photoluminescence of Amorphous Silicon Oxycarbide Films

Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 649 ◽  
Author(s):  
Jie Song ◽  
Rui Huang ◽  
Yi Zhang ◽  
Zewen Lin ◽  
Wenxing Zhang ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Nitrogen Doping ◽  
Silicon Oxycarbide ◽  
Chemical Bonds ◽  
X Ray ◽  
Nitrogen Doped ◽  
Orange Yellow ◽  
Luminescent Films ◽  
Decay Dynamic ◽  
Luminescent Centers

The effect of nitrogen doping on the photoluminescence (PL) of amorphous SiCxOy films was investigated. An increase in the content of nitrogen in the films from 1.07% to 25.6% resulted in red, orange-yellow, white, and blue switching PL. Luminescence decay measurements showed an ultrafast decay dynamic with a lifetime of ~1 ns for all the nitrogen-doped SiCxOy films. Nitrogen doping could also widen the bandgap of SiCxOy films. The microstructure and the elemental compositions of the films were studied by obtaining their Raman spectra and their X-ray photoelectron spectroscopy, respectively. The PL characteristics combined with an analysis of the chemical bonds configurations present in the films suggested that the switching PL was attributed to the change in defect luminescent centers resulting from the chemical bond reconstruction as a function of nitrogen doping. Nitrogen doping provides an alternative route for designing and fabricating tunable and efficient SiCxOy-based luminescent films for the development of Si-based optoelectronic devices.

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