Freeze-dried MoS2 sponge electrodes for enhanced electrochemical energy storage

2017 ◽  
Vol 46 (7) ◽  
pp. 2122-2128 ◽  
Author(s):  
Suresh Kannan Balasingam ◽  
Minoh Lee ◽  
Byung Hoon Kim ◽  
Jae Sung Lee ◽  
Yongseok Jun

High surface area MoS2 sponge electrodes were synthesized via a facile hydrothermal method followed by a freeze drying process and showed high specific capacitance and better charge storage behavior.

RSC Advances ◽  
2016 ◽  
Vol 6 (61) ◽  
pp. 56421-56428 ◽  
Author(s):  
Vivek Sharma ◽  
Santimoy Khilari ◽  
Debabrata Pradhan ◽  
Paritosh Mohanty

High surface area hypercrosslinked polyaniline samples synthesized by solvothermal method have shown efficient performance for gas sorption and charge storage.


Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 40 ◽  
Author(s):  
Kang-Kai Liu ◽  
Biao Jin ◽  
Long-Yue Meng

In this study, three-dimensional glucose/graphene-based aerogels (G/GAs) were synthesized using the hydrothermal reduction and CO2 activation method. Graphene oxide (GO) was used as a matrix, and glucose was used as a binder for the orientation of the GO morphology in an aqueous media. We determined that G/GAs exhibited narrow mesopore size distribution, a high surface area (763 m2 g−1), and hierarchical macroporous and mesoporous structures. These features contributed to G/GAs being promising adsorbents for the removal of CO2 (76.5 mg g−1 at 298 K), CH4 (16.8 mg g−1 at 298 K), and H2 (12.1 mg g−1 at 77 K). G/GAs presented excellent electrochemical performance, featuring a high specific capacitance of 305.5 F g−1 at 1 A g−1, and good cyclic stability of 98.5% retention after 10,000 consecutive charge-discharge cycles at 10 A g−1. This study provided an efficient approach for preparing graphene aerogels exhibiting hierarchical porosity for gas adsorption and supercapacitors.


Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 839
Author(s):  
Karina Jasińska ◽  
Bartłomiej Zieniuk ◽  
Dorota Nowak ◽  
Agata Fabiszewska

The study aimed to evaluate the impact of selected factors of the freeze-drying process on the hydrolytic and synthetic activity of the extracellular lipases of Y. lipolytica KKP 379 and to attempt the use of the crude enzyme preparation as a biocatalyst in the synthesis of geranyl 4-hydroxyphenylpropanoate. Antioxidant and antibacterial properties of the geranyl ester derivative were also investigated in order to evaluate their usefulness as a novel food additive. The studies confirmed that freeze-drying was an effective method of dehydrating yeast supernatant and allowed for obtaining lyophilizates with low water activity from 0.055 to 0.160. The type and concentration of the additive (2–6% whey protein hydrolyzate, 0.5% and 1% ammonium sulphate) had a significant effect on the hydrolytic activity of enzyme preparations, while the selected variants of drying temperature during the freeze-drying process were not significant (10 °C and 50 °C). Low yield of geranyl 4-hydroxyphenylopropionate was shown when the lyophilized supernatant was used (5.3%), but the yield of ester synthesis increased when the freeze-dried Y. lipolytica yeast biomass was applied (47.9%). The study confirmed the antioxidant properties of the synthesized ester by the DPPH• and CUPRAC methods, as well as higher antibacterial activity against tested bacteria than its precursor with 0.125 mM MIC (minimal inhibitory concentration) against L. monocytogenes.


2020 ◽  
Vol 981 ◽  
pp. 17-22
Author(s):  
Amir Luqman Sanusi ◽  
Nurul Khairiyyah Mohd Zain ◽  
Izan Izwan Misnon ◽  
Ahmad Salihin Samsudin ◽  
Rajan Jose

Metal-organic frameworks (MOFs) composed by coordination bonds between metal ion with organic linker has a uniform combination of micro and mesoporous structures has been used for several application including battery supercapacitor hybrid. (BSH). In BSH, MOF offer several advantages including high surface area, porous, and structure tunability. This paper reports the synthesis of ternary MOF of copper (Cu), nickel (Ni) and cobalt (Co) with 1,4-benzenedicarboxylic acid. The Co/Cu/Ni-MOF is synthesized using hydrothermal method at 160 °C for 12h and further develop as a BSH electrode. The physicochemical properties of MOF were characterized using FESEM, FTIR, XRD, BET and the electrochemical properties were evaluated using cyclic voltammetry (CV), charge-discharge cycling (CDC) and electrochemical impedance spectroscopy (EIS). Electrochemical analysis indicated that the MOF has high specific capacitance (CS) of 591 F g-1 at a current density of 1 A g-1 and 519 F g-1 at scan rate of 2 mV s-1, and possess low series resistance (RS) of 0.44 Ω and equivalent distributed resistance (Rd) of 1.07 Ω.


2020 ◽  
Vol 45 (3) ◽  
pp. 189-196
Author(s):  
S. Said ◽  
T. Maulana ◽  
S. Setiorini ◽  
G.E. Ibrahim ◽  
M.N. Ramadhan ◽  
...  

The objective of the current study was to investigate the effect of addition an amino acid or its combination with EDTA on DNA integrity and morphometry sperm heads of freeze-dried bovine spermatozoa. Spermatozoa were freeze-dried in medium with the addition of an amino acid glycine, cysteine, glutamine, or its combination with EDTA. Sperm head morphometry was identified at 400X magnification using Axio Vision(Zeiss Company, Germany), while for membrane plasma integrity (MPI) determined by calculation of the percentage of spermatozoa having intact plasma membrane by osmotic resistance test method and DNA integrity analysis using acridine orange staining. Sperm head had declined in size after the freeze-drying process, MPI of FD spermatozoa gradually increased significantly when FD solution was added with an amino acid solution (glycine, cysteine) and its combination with EDTA. DNA integrity of all freeze-dried spermatozoa treatments was remaining intact, no significantly different (P>0.01) among treatments. The present study concluded that the addition of an amino acid (glycine, cysteine) or its combination with EDTA could be reduced morphometric sperm heads and plasma membrane damage of freeze-dried bovine spermatozoa, however, DNA integrity of bovine sperm nucleus remaining intact after the freeze-drying process without addition both amino acids and EDTA. 


2019 ◽  
Vol 69 (1) ◽  
pp. 17-32
Author(s):  
Maja Preskar ◽  
Tomislav Vrbanec ◽  
Franc Vrečer ◽  
Primož Šket ◽  
Janez Plavec ◽  
...  

Abstract Ibuprofen, a weakly acidic non-steroidal anti-inflammatory drug having poor aqueous solubility, is a challenging drug for the development of pharmaceutical formulations, resulting in numerous research attempts focusing on improvement of its solubility and consequently bioavailability. Most studies have been done for solid dosage forms, with very little attention paid to parenterals. Hence, the main purpose of the present study was to enhance ibuprofen solubility as a result of formulation composition and the freeze drying process. Moreover, the purpose was to prepare a freeze dried dosage form with improved ibuprofen solubility that could, after simple reconstitution with water for injection, result in an isotonic parenteral solution. Solubility of ibuprofen was modified by various excipients suitable for parenteral application. Drug interactions with selected excipients in the final product/lyophilisate were studied by a combined use of XRPD, DSC, Raman and ss-NMR. Analyses of lyophilized samples showed solubility enhancement of ibuprofen and in situ formation of an ibuprofen salt with the alkaline excipients used.


2020 ◽  
Vol 6 (4) ◽  
pp. 73 ◽  
Author(s):  
Rashma Chaudhary ◽  
Subrata Maji ◽  
Rekha Goswami Shrestha ◽  
Ram Lal Shrestha ◽  
Timila Shrestha ◽  
...  

Hierarchically porous activated carbon materials from agro-waste, Jackfruit seeds are prepared by a chemical activation method involving the treatment with zinc chloride (ZnCl2) at different temperatures (600–1000 °C). The electrochemical supercapacitance performances of the prepared materials were studied in an aqueous electrolyte (1 M sulfuric acid, H2SO4) in a three-electrode system. Jackfruit seed carbons display nanoporous structures consisting of both micro- and mesopore architectures and they are amorphous in nature and also contain oxygenated surface functional groups, as confirmed by powder X-ray diffraction (pXRD), Raman scattering, and Fourier-transformed infrared (FTIR) spectroscopy, respectively. The surface areas and pore volumes were found to be 1216.0 to 1340.4 m2·g−1 and 0.804 to 1.144 cm3·g−1, respectively, demonstrating the better surface textural properties compared to the commercial activated carbons. Due to the high surface area, large pore volume, and well developed hierarchical micro- and mesoporosity, the optimal sample achieved a high specific capacitance of 292.2 F·g−1 at 5 mV·s−1 and 261.3 F·g−1 at 1 A·g−1 followed by outstanding high rate capability. The electrode sustained 71.6% capacity retention at a high current density of 20 A·g−1. Furthermore, the electrode displayed exceptional cycling stability with small capacitance loss (0.6%) even after 10,000 charging–discharging cycles, suggesting that Jackfruit seed would have potential in low-cost and scalable production of nanoporous carbon materials for supercapacitors applications.


2012 ◽  
Vol 195-196 ◽  
pp. 441-446
Author(s):  
Jun Liu ◽  
Shi Wei Zhang ◽  
Zhi Jun Zhang

In this paper, the vacuum freeze-drying experiments of both antler slices and whole antlers are reported in details. The moisture content and the eutectic temperature of antler were measured. A 22 h process curve of antler slice freeze drying was obtained. The freeze drying process of whole antler was also investigated. The microscopic tissue structure was observed and chemical compositions were analyzed for those freeze-dried whole antlers in comparison with the traditional water boiling and hot air drying method. More nutrients were retained for freeze drying in addition to the better physical properties than traditional drying.


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