scholarly journals Effects of Precursors and Carbon Nanotubes on Electrochemical Properties of Electrospun Nickel Oxide Nanofibers-Based Supercapacitors

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5656
Author(s):  
Reziwanguli Aihemaitituoheti ◽  
Nuha A. Alhebshi ◽  
Tuerdimaimaiti Abudula

Supercapacitors have been considered as one of the main energy storage devices. Recently, electrospun nanofibers have served as promising supercapacitor electrodes because of their high surface area, high porosity, flexibility, and resistance to aggregation. Here, we investigate the effects of electrospinning parameters and nickel precursors on the nanostructure of electrospun nickel oxide (NiO), as well as on their electrochemical performance as supercapacitor electrodes. In contrast to the case of using nickel nitrate, increasing the nickel acetate molar concentration maintains the flexible fibrous sheet morphology of the as-spun sample during the polycondensation and calcination of NiO. As a result, our flexible electrode of NiO nanofibers derived from nickel acetate (NiO-A) exhibits much better electrochemical performance values than that of nickel nitrate-derived NiO. To further improve the electrochemical storage performance, we combined NiO-A nanofibers with single-walled carbon nanotubes (CNTs) as a hybrid electrode. In both half-cell and full-cell configurations, the hybrid electrode displayed a higher and steadier areal capacitance than the NiO-A nanofibers because of the synergetic effect between the NiO-A nanofibers and CNTs. Altogether, this work demonstrates the potency of the hybrid electrodes combined with the electrospun NiO-A nanofibers and CNTs for supercapacitor applications.

2016 ◽  
Vol 8 (37) ◽  
pp. 24918-24923 ◽  
Author(s):  
Amir A. Bakhtiary Davijani ◽  
H. Clive Liu ◽  
Kishor Gupta ◽  
Satish Kumar

2020 ◽  
Vol 16 (4) ◽  
pp. 617-624 ◽  
Author(s):  
Yao Feng ◽  
Ran Wang ◽  
Juanjuan Yin ◽  
Fangke Zhan ◽  
Kaiyue Chen ◽  
...  

Background: 4-nitrophenol (4-NP) is one of the pollutants in sewage and harmful to human health and the environment. Cu is a non-noble metal with catalytic reduction effect on nitro compounds, and.has the advantages of simple preparation, abundant reserves, and low price. Carbon nanotubes (CNT) are widely used for substrate due to their excellent mechanical stability and high surface area. In this study, a simple method to prepare CNT-Cu2O by controlling different reaction time was reported. The prepared nanocomposites were used to catalyze 4-NP. Methods: CNTs and CuCl2 solution were put into a beaker, and then ascorbic acid and NaOH were added while continuously stirring. The reaction was carried out for a sufficiently long period of time at 60°C. The prepared samples were dried in a vacuum at 50°C for 48 h after washing with ethyl alcohol and deionized water. Results: Nanostructures of these composites were characterized by scanning electron microscope and transmission electron microscopy techniques, and the results at a magnification of 200 nanometers showed that Cu2O was distributed on the surface of the CNTs. In addition, X-ray diffraction was performed to further confirm the formation of Cu2O nanoparticles. The results of ultraviolet spectrophotometry showed that the catalytic effect of the compound on 4-NP was obvious. Conclusions: CNTs acted as a huge template for loading Cu2O nanoparticles, which could improve the stability and cycle performance of Cu2O. The formation of nanoparticles was greatly affected by temperature and the appropriate concentration, showing great reducibility for the 4-NP reduction reaction.


2021 ◽  
Vol 22 (9) ◽  
pp. 4498
Author(s):  
Md. Motiar Rahman ◽  
Mst Gulshan Ara ◽  
Mohammad Abdul Alim ◽  
Md. Sahab Uddin ◽  
Agnieszka Najda ◽  
...  

Mesoporous carbon is a promising material having multiple applications. It can act as a catalytic support and can be used in energy storage devices. Moreover, mesoporous carbon controls body’s oral drug delivery system and adsorb poisonous metal from water and various other molecules from an aqueous solution. The accuracy and improved activity of the carbon materials depend on some parameters. The recent breakthrough in the synthesis of mesoporous carbon, with high surface area, large pore-volume, and good thermostability, improves its activity manifold in performing functions. Considering the promising application of mesoporous carbon, it should be broadly illustrated in the literature. This review summarizes the potential application of mesoporous carbon in many scientific disciplines. Moreover, the outlook for further improvement of mesoporous carbon has been demonstrated in detail. Hopefully, it would act as a reference guidebook for researchers about the putative application of mesoporous carbon in multidimensional fields.


2021 ◽  
Vol 44 (1) ◽  
pp. 129-140
Author(s):  
Agha Kashif ◽  
Sumaira Aftab ◽  
Muhammad Javaid ◽  
Hafiz Muhammad Awais

Abstract Topological index (TI) is a numerical invariant that helps to understand the natural relationship of the physicochemical properties of a compound in its primary structure. George Polya introduced the idea of counting polynomials in chemical graph theory and Winer made the use of TI in chemical compounds working on the paraffin's boiling point. The literature of the topological indices and counting polynomials of different graphs has grown extremely since that time. Metal-organic network (MON) is a group of different chemical compounds that consist of metal ions and organic ligands to represent unique morphology, excellent chemical stability, large pore volume, and very high surface area. Working on structures, characteristics, and synthesis of various MONs show the importance of these networks with useful applications, such as sensing of different gases, assessment of chemicals, environmental hazard, heterogeneous catalysis, gas and energy storage devices of excellent material, conducting solids, super-capacitors and catalysis for the purification, and separation of different gases. The above-mentioned properties and physical stability of these MONs become a most discussed topic nowadays. In this paper, we calculate the M-polynomials and various TIs based on these polynomials for two different MONs. A comparison among the aforesaid topological indices is also included to represent the better one.


2021 ◽  
Vol 18 ◽  
Author(s):  
Raja Murugesan ◽  
Sureshkumar Raman

: At present treatment methods for cancer are limited, partially due to the solubility, poor cellular distribution of drug molecules and, the incapability of drugs to annoy the cellular barriers. Carbon nanotubes (CNTs) generally have excellent physio-chemical properties, which include high-level penetration into the cell membrane, high surface area and high capacity of drug loading by in circulating modification with bio-molecules, project them as an appropriate candidate to diagnose and deliver drugs to prostate cancer (PCa). Additionally, the chemically modified CNTs which have excellent 'Biosensing' properties therefore makes it easy for detecting PCa without fluorescent agent and thus targets the particular site of PCa and also, Drug delivery can accomplish a high efficacy, enhanced permeability with less toxic effects. While CNTs have been mainly engaged in cancer treatment, a few studies are focussed on the diagnosis and treatment of PCa. Here, we detailly reviewed the current progress of the CNTs based diagnosis and targeted drug delivery system for managing and curing PCa.


2021 ◽  
Author(s):  
Yong-Mei Wang ◽  
Xinxin Zhang ◽  
Dingyi Yang ◽  
Liting Wu ◽  
Jiaojiao Zhang ◽  
...  

Abstract The high porosity, controllable size, high surface area, and chemical versatility of a metal-organic framework (MOF) enable it a good material for a triboelectric nanogenerator (TENG), and some MOFs have been incorporated in the fabrication of TENGs. However, the understanding of effects of MOFs on the energy conversion of a TENG is still lacking, which inhibits the improvement of the performance of MOF-based TENGs. Here, UiO-66-NH2 MOFs were found to significantly increase the power of a TENG and the mechanism was carefully examined. The electron-withdrawing ability of Zr-based UiO-66-family MOFs was enhanced by designing the amino functionalized 1,4-terephthalic acid (1,4-BDC) as ligand. The chemically modified UiO-66-NH2 was found to increase the surface roughness and surface potential of a composite film with MOFs embedded in polydimethylsiloxane (PDMS) matrix. Thus the total charges due to the contact electrification increased significantly. The composite-based TENG was found to be very durable and its output voltage and current were 4 times and 60 times higher than that of a PDMS-based TENG. This work revealed an effective strategy to design MOFs with excellent electron-withdrawing abilities for high-performance TENGs.


2019 ◽  
Vol 41 (5) ◽  
pp. 805-805
Author(s):  
Li Fanghao Li Fanghao ◽  
Li Chenjie Li Chenjie ◽  
Chen Junyi Chen Junyi ◽  
Wang Kuiwu Wang Kuiwu ◽  
Zhang Haijiang Zhang Haijiang ◽  
...  

A series of tungstophosphoric acid (H3PW12O40; HPW) loaded on metal oxide catalysts, namely H3PW12O40/M (M= TiO2, CeO2, ZrO2) was prepared by initial wetting impregnation method and their catalytic performances were also investigated during the condensation reaction of benzaldehyde with glycol. Among them, the 20 wt% H3PW12O40/TiO2 catalyst demonstrated highly active with superior acetal yield (90.1 %) and excellent durability. The high activity of the catalyst derived from high surface area, ultra-strong Brand#248;nsted acidity and synergetic effect of Brand#248;nsted-Lewis acid. Response surface methodology (RSM) based on Box-Behnken design (BBD) was used to optimize the course of the condensation reaction of benzaldehyde with glycol, and the optimal benzaldehyde glycol acetal yield (93.4 %) could be obtained. The optimized yield and the experimental results are similar. Moreover, under optimal reaction conditions, the activation energy (Ea) of reaction could be obtained through the kinetic study of the irreversible parallel reaction model, and the Ea was 23.24 kJ/mol.


2019 ◽  
Vol 966 ◽  
pp. 444-450 ◽  
Author(s):  
Fandi Angga Prasetya ◽  
Ufafa Anggarini ◽  
Yudha Zakaria ◽  
Rosa Dwi Sasqia Putri

Supercapacitor require electrode which has high surface area so that it able to store large amounts of charge. In this study, electrode was synthesized from carbon of Borassus Flabellifer L fiber which was carried out through activation and carbonization processes. Raw material was calcined at 400°C for 4 hours followed by activation with NaOH 1 M. The carbonization was then conducted in Nitrogen gas flowing by temperature variations; 650°C, 750°C, and 850°C with a constant heating rate of 20 °C/min. Based on XRD data, it was shown that the material has formed Reduced graphene Oxide (RGO) which has main peaks at (2θ) 240 and 440 with higher purity in higher temperature. SEM results clarified more pores formation at higher temperature which is mesoporous. Cyclic Voltammetry (CV) test was done to determine the capacitance value. By RGO forming with high porosity, it is suitable for supercapacitor electrode application and CV test has examined that heating of Borassus Flabelifer L fiber at 850°C with 5 mV/s scan rate has the highest specific capacitance by 8.25 F/gram with Energy density is 4.125 watt/gram.


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