Adsorption behavior of cross-linked chitosan modified by graphene oxide for Cu(Ⅱ) removal

Cross-linked chitosan(CS),cross-linked chitosan/graphene(CS/RGO10) and cross-linked chitosan/graphene oxide(CS/GO10) were prepared as adsorbents for Cu(Ⅱ).The effects of pH,contact time,adsorbent dosage and initial concentration of Cu(Ⅱ) on the adsorbing abilities of CS,CS/RGO10 and CS/GO10 to Cu(Ⅱ) were investigated.The results demonstrate that the adsorption capacities of CS/GO10 and CS/RGO10 are greater than that of CS,especially at pH 5.0 and the adsorption capacities are 202.5,150 and 137.5 mg/g,respectively.Their behaviors obey the Freundlich isotherm model very well.Additionally,CS/GO10 has the shortest time to achieve adsorption equilibrium among them and can be used as a perspective adsorbent for Cu(Ⅱ).

Graphene oxide-composited chitosan scaffold contributes to functional recovery of injured spinal cord in rats

The study illustrates that graphene oxide nanosheets can endow materials with continuous electrical conductivity for up to 4 weeks. Conductive nerve scaffolds can bridge a sciatic nerve injury and guide the growth of neurons;however, whether the scaffolds can be used for the repair of spinal cord nerve injuries remains to be explored. In this study, a conductive graphene oxide composited chitosan scaffold was fabricated by genipin crosslinking and lyophilization. The prepared chitosan-graphene oxide scaffold presented a porous structure with an inner diameter of 18–87 μm, and a conductivity that reached 2.83 mS/cm because of good distribution of the graphene oxide nanosheets, which could be degraded by peroxidase. The chitosan-graphene oxide scaffold was transplanted into a T9 total resected rat spinal cord. The results show that the chitosan-graphene oxide scaffold induces nerve cells to grow into the pores between chitosan molecular chains, inducing angiogenesis in regenerated tissue, and promote neuron migration and neural tissue regeneration in the pores of the scaffold, thereby promoting the repair of damaged nerve tissue. The behavioral and electrophysiological results suggest that the chitosan-graphene oxide scaffold could significantly restore the neurological function of rats. Moreover, the functional recovery of rats treated with chitosangraphene oxide scaffold was better than that treated with chitosan scaffold. The results show that graphene oxide could have a positive role in the recovery of neurological function after spinal cord injury by promoting the degradation of the scaffold, adhesion, and migration of nerve cells to the scaffold. This study was approved by the Ethics Committee of Animal Research at the First Affiliated Hospital of Third Military Medical University(Army Medical University)(approval No. AMUWEC20191327) on August 30, 2019.

Electrodeposition of chitosan/graphene oxide conduit to enhance peripheral nerve regeneration

Currently available commercial nerve guidance conduits have been applied in the repair of peripheral nerve defects.However,a conduit exhibiting good biocompatibility remains to be developed.In this work,a series of chitosan/graphene oxide(GO)films with concentrations of GO varying from 0-1 wt%(collectively referred to as CHGF-n)were prepared by an electrodeposition technique.The effects of CHGF-n on proliferation and adhesion abilities of Schwann cells were evaluated.The results showed that Schwann cells exhibited elongated spindle shapes and upregulated expression of nerve regeneration-related factors such as Krox20(a key myelination factor),Zeb2(essential for Schwann cell differentiation,myelination,and nerve repair),and transforming growth factorβ(a cytokine with regenerative functions).In addition,a nerve guidance conduit with a GO content of 0.25%(CHGFC-0.25)was implanted to repair a 10-mm sciatic nerve defect in rats.The results indicated improvements in sciatic functional index,electrophysiology,and sciatic nerve and gastrocnemius muscle histology compared with the CHGFC-0 group,and similar outcomes to the autograft group.In conclusion,we provide a candidate method for the repair of peripheral nerve defects using free-standing chitosan/GO nerve conduits produced by electrodeposition.

Enhanced Removal of Phosphates by the Adsorbent Consisting of Iron Oxide Loaded on Porous Chitosan/Cellulose Acetate Particle

The effective and economical removal of phosphates from aqueous solution, mostly applied in waste water treatment, is one of the significant issues globally. Removal of phosphates ions in aqueous solution was analysed by chitosan blended with cellulose acetate, and iron oxide loaded chitosan-cellulose acetate adsorbents. The adsorbents were made in the form of beads. Batch experiments were performed to investigate the performance of the beads under various conditions on phosphate adsorption. Contact time, effect of initial phosphate concentration, adsorbent dosage, pH and temperature were investigated. Zeta potential measurements were also undertaken. The results showed that the adsorption process was highly pH dependent. The adsorption kinetics data were modelled with the application of adsorption reaction models and adsorption diffusion models. The results revealed that the pseudo 2nd order model was the best fitting in all cases. The experimental data were tested with Langmuir and Freundlich isotherms. The equilibrium data were well fitted to the Langmuir isotherm model with a maximum adsorption capacity of 958 μg/g. The Freundlich isotherm model also had a close fit with a maximum adsorption of 233 μg/g, which was very close to the experimental maximum adsorption. The mechanism of adsorption followed two stages in which the first one was fast followed by a slower gradual stage. SEM images showed that the adsorbent was macroporous. Fourier Transform Infrared Red (FT-IR) Spectroscopy, X-ray Diffraction Spectroscopy (XRD) and X-ray photoelectron Spectroscopy (XPS) showed that the phosphate adsorption on the HFO-CS/CA beads was due to surface complexes, and mainly involved Nitrogen atoms. HFO loading also increased surface area.

Biomimetic Mineralizated and Nano-Ag Loadedgraphene Oxide/Chitosan Hybrid Scaffold for Osteoinduction and Antibacterium

Graphene oxide (GO) is a graphene derivatives that has oxygen-containing functional groups on the graphene basal plane, such as hydroxyl, carbonyl, epoxy and carboxyl groups. GO is considered as a promising material for biological applications owing to its excellent surface functionalizability, high specific suface area and good biocompatibility. In this study, GO/chitosan hybrid scaffolds were prepared for tissue engineering. Nano silver was loaded into the scaffold to improve its antibacterial ability and biomimetic Ca-P coatings were deposited on the scaffold surface to enhance its osteoconductivity. First, GO was prepared by the chemical oxidization of graphite. Secondly, nano-Ag loaded GO was prepared by chemical reducing Ag ions in GO solutions. Then, nano-Ag loaded GO solution was mixed with CS solution to form GO-CS gel. Chitosan (CS) and GO were crosslinked by electrostatic interactions between oxygen-containing functional groups of GO and NH2 groups of CS. The gel were freeze dried to produce nano-Ag loaded GO/CS hybrid porous scaffolds. Finally, the as-prepared scaffolds were immersed the into a supersaturated calcium phosphate solution (SCPS) for 7 days to deposite CaP coatings on the surface of the micropores. SEM images showed that nano-Ag uniformly distributed in the scaffold and the CaP covered most of the scaffold surfaces. In vitro cell culture and antimicrobial test indicated the biomimetic mineralized Ag-CS-GO scaffolds have good osteoconductivity and bactericidal ability.

Adsorption of Quaternized-chitosan-modified Reduced Graphene Oxide

A novel quaternized-chitosan-modified reduced graphene oxide（HACC-RGO） combined the adsorption advantages of RGO and 2-Hydroxypropyltrimethyl ammonium chloride chitosan（HACC）. The adsorption property of HACC-RGO sheets for methyl orange（MO） was demonstrated and compared with RGO and HACC. The removal ratios of HACC-RGO sheets reached 92.6% for MO after a 24 h adsorption. The adsorption kinetics, isotherms and thermodynamics were investigated to indicate that the kinetics and equilibrium adsorptions were well-described by pseudo-second-order kinetic and Freundlich isotherm model, respectively. The thermodynamic parameters suggested that the adsorption process was spontaneous and endothermic in nature. Moreover, monodisperse HACC-RGO/CS beads were fabricated by the microfluidic method. The adsorption and desorption of HACC-RGO/CS beads for MO were studied. After three adsorptiondesorption cycles, the adsorption capacity remained above 55% and the desorption capacity was not below 70%. The HACC-RGO/CS beads can be reused and have great potential applications in removing organic dyes from polluted water.

Manufacturing N,O-carboxymethyl chitosan-reduced graphene oxide under freeze-dying for performance improvement of Li-S battery

Lithium-sulfur(Li-S) batteries can provide far higher energy density than currently commercialized lithium ion batteries, but challenges remain before it they are used in practice.One of the challenges is the shuttle effect that originates from soluble intermediates, like lithium polysulfides. To address this issue, we report a novel laminar composite, N,O-carboxymethyl chitosan-reduced graphene oxide(CC-rGO), which is manufactured via the self-assembly of CC onto GO and subsequent reduction of GO under an extreme condition of 1 Pa and-50°C. The synthesized laminar CC-rGO composite is mixed with acetylene black(AB) and coated on a commercial polypropylene(PP) membrane, resulting in a separator(CC-rGO/AB/PP) that can not only completely suppress the polysulfides penetration, but also can accelerate the lithium ion transportation, providing a Li-S battery with excellent cyclic stability and rate capability. As confirmed by theoretic simulations, this unique feature of CC-rGO is attributed to its strong repulsive interaction to polysulfide anions and its benefit for fast lithium ion transportation through the paths paved by the heteroatoms in CC.

Incorporation of Nano-Zinc Oxide in Lamellar Zirconium Phosphate: Synthesis and Characterization

In order to provide ultraviolet barrier, antifungal and antibacterial properties, nano-zinc oxide (ZnO) was added to lamellar zirconium phosphate (ZrP). The phosphate was synthesized via reaction of zirconium oxychloride octahydrate and phosphoric acid following its chemical modification with Jeffamine and nano-ZnO. Diffractometric, morphological, thermal, structural and relaxometric evaluations were conducted. Fourier transform infrared spectroscopy (FTIR) revealed increase of the area between 4000 - 3000 cm-1 due to the formation of ionic specie PO? +NH3-[C-(H)(CH3)-CH2-O-(C-(H)(CH3)-CH2-O)8-(CH2-CH2-O-CH3)] and nano-ZnO particles. Wide-angle X-ray diffraction indicated that intercalation of Jeffamine was successful. Thermogravimetry confirmed that nano-ZnO particle forced the expulsion of Jeffamine outside ZrP galleries. Scanning electron microscopy evidenced the Jeffamine intercalation and sample heterogeneity. Hydrogen molecular relaxation indicated the increase of molecular rigidity owing to the formation of ionic specie and the addition of nano-ZnO particles. It was postulated that a multifunctional and miscellaneous material constituted by as prepared ZrP, some delaminated ZrP platelets and nano-ZnO particles was achieved. The material has potential for usage as filler in polymeric composites.

Antioxidative effect of folate-modified chitosan nanoparticles

Objective:To evaluate the potency of carboxymethyl chitosan-2,2' ethylenedioxy bisethylamine-folate(CMC-EDBE-FA) on tissue injury,antioxidant status and glutathione system in tissue mitochondria and serum against nicotine-induced oxidative stress in mice.Methods: CMC-EDBE-FA was prepared on basis of carboxymethyl chitosan tagged with folic acid by covalently linkage through 2,2' ethylenedioxy bis-ethylamine.Animals were divided into four groups,i.e.,control,nicotine(1 mg/kg bw/day),CMC-EDBE-FA(1 mg/kg bw/day) and nicotine(1 mg/kg bw/day) and CMC-EDBE-FA(1 mg/kg bw/day) for 7 days.Levels of lipid peroxidation, oxidized glutathione level,antioxidant enzyme status and DNA damage were observed and compared.Results:The significantly increase of lipid peroxidation,oxidized glutathione levels and DNA damage was observed in nicotine treated group as compared with control group;those were significantly reduced in CMC-EDBE-FA supplemented group.Moreover,significantly reduced antioxidant status in nicotine treated group was effectively ameliorated by the supplementation of CMC-EDBE-FA.Only CMC-EDBE-FA treated groups showed no significant change as compared with control group;rather than it repairs the tissue damage of nicotine treated group.Conclusions:These findings suggest that CMC-EDBE-FA is non-toxic and ameliorates nicotine-induced toxicity.

Gelation and Swelling Behavior of Oxidized Konjac Glucomannan/Chitosan Hydrogel

The gelating and swelling mechanisms of the hydrogel formed from oxidized konjac glucomannan (OKGM) and chitosan (CS) were studied by Fourier transform infrared (FT-IR) spectrometry. FT-IR spectra illustrate that the interaction of polysaccharides forms the hydrogen bonds and interchain salt bonds and the dissocation of which dominates the swelling behavior in buffer solutions of different pH. The concentration of salt ion has effect on swelling behavior through the difference of salt ion concentration between in solution and in network of hydrogel, which causes penetrating pressure. Moreover, the Swelling degree and hydrogel strength could be modulated by varying conditions. It is indicated that the hydrogel has pH-sensitive and salt ion sensitive properties. The prepared optimum condition selected by varying conditions is thatr=0.2;t=30 min;T p

Effect of Molecular Weight and Structure on Antitumor Activity of Oxidized Chitosan

Various low molecular weight chitosans were prepared by oxidative degradation with H2O2, and characterized by IR,13C-NMR and gel permeation chromatography. Their carboxylic contents increased with decrease in molecular weight (M w ). The antitumor test of the samples against sarcoma 180 tumors suggested that the water-soluble chitosan with higherM w have higher inhibitory ratioin vivo. The introduction of carboxylic group is advantage to water-solubility of chitosan, but more acidic groups might decrease the function of amino groups of chitosan against sarcoma 180 tumor.

Preparation of Fe_(3)O_(4) Film by in-situ Oxidative Hydrolysis on Chitosan

The Fe3O4 films were prepared by in-situ oxidative hydrolysis on chitosan. The structures and characteristics of the prepared Fe3O4 films were investigated by X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, atom force microscopy （AFM）, vibrating sample magnetometry （VSM） and thermogravimetric-differentia thermal analysis （TG-DTA）. The results show that, （1） the as-synthesized Fe3O4 films are pure Fe3O4 with cubic inverse spinel structure; （2） the network structured film can be obtained at lower temperature, and the compact particle film at higher temperature; （3） the prepared Fe3O4 films are super-paramagnetic, and the saturation magnetization is improved with increasing the reaction temperature, which is 49.03 emu/g at 80℃; （4） the temperature of phase transformation from Fe3O4 to a-Fe2O3 is about 495℃. Besides, the formation mechanism of Fe3O4 film was also proposed.

还原氧化石墨烯/壳聚糖自组装棉织物的制备及性能

首先,以乙二醛和壳聚糖(CS)对纯棉织物进行改性制备了CS改性棉织物;然后,将CS改性棉织物经氧化石墨烯(GO)分散液浸渍;最后,将吸附沉积在棉织物上的GO还原为还原氧化石墨烯(RGO),制备了RGO/CS-棉织物。采用SEM、FTIR和Raman光谱对其进行了表征,考察了CS质量分数、GO分散液质量浓度对RGO/CS-棉织物导电、抗紫外线和抑菌性能的影响,并对其耐洗性进行了测试。结果表明,RGO/CS-棉织物表面沉积的GO已较充分还原为RGO,表面覆盖了一层连续的RGO/CS薄膜;RGO/CS-棉织物导电性随着GO分散液质量浓度的增加而逐渐增强;经质量分数2.00%的CS溶液改性和质量浓度5 g/L的GO分散液处理并还原后的RGO/CS-棉织物具有最佳的导电性,表面电阻为1.02 kΩ/cm;RGO与CS协同增强了RGO/CS-棉织物的抑菌性能,抑菌率最高达95%;经质量分数0.50%的CS溶液改性和质量浓度3 g/L的GO分散液处理并还原后的RGO/CS-棉织物经过30~50次皂洗洗涤后,导电、抑菌和抗紫外线性能变化较小。

壳聚糖/无机物复合吸附剂去除废水中重金属离子的研究进展

壳聚糖优异的无毒性、生物相容性、由于丰富的官能团而具备的较强吸附性以及成本低廉的特点使其有望成为潜在的优良吸附材料。但未改性的壳聚糖在酸性条件下易发生水解,吸附性能弱,通过与其他材料复合可以增加壳聚糖的吸附位点、力学强度,复合后的材料能够适应不同条件下的废水吸附环境。本文论述了当今热点的壳聚糖/磁性纳米颗粒(CS/MNPs)、壳聚糖/氧化石墨烯(CS/GO)、壳聚糖/粘土矿物(CS/CM)、壳聚糖/生物炭(CS/BC)等壳聚糖/无机复合吸附剂特性和优势进行归纳总结,并对这几种复合材料对常见重金属的去除现状进行了综述。

载富血小板血浆水凝胶对L929细胞氧化损伤的保护作用

背景:在慢性创面愈合过程中,活性氧的过量生成可能会损害L929成纤维细胞的功能,从而延缓创面修复,因此保护成纤维细胞免受氧化应激的影响对于促进创面愈合非常重要。目的:评估羧甲基壳聚糖-氧化硫酸软骨素/富血小板血浆(CMC-OCS/PRP)水凝胶对H2O2刺激下L929细胞的保护作用。方法:制备CMC-OCS/PRP水凝胶,表征水凝胶的微观形貌、降解性能、清除H2O2与羟基自由基的能力及生物相容性。取生长状态良好的L929细胞,分5组培养:对照组常规培养,H2O2组加入H2O2,CMC-OCS组加入羧甲基壳聚糖-氧化硫酸软骨素水凝胶浸提液+H2O2,PRP组加入富血小板血浆凝胶浸提液+H2O2,CMC-OCS/PRP组加入羧甲基壳聚糖-氧化硫酸软骨素/富血小板血浆水凝胶浸提液处理+H2O2,每组先加入水凝胶浸提液处理6 h,然后再加入H2O2处理24 h。培养结束后,检测细胞活性氧及丙二醛水平,细胞凋亡、胶原纤维Ⅰ蛋白表达。在加入H2O2的情况下,将上述水凝胶浸提液分别与L929成纤维细胞直接或间接共培养36 h,通过划痕实验、Transwell小室实验检测细胞的迁移能力。结果与结论:①CMC-OCS/PRP水凝胶具有均匀相互关联的多孔结构及良好的降解能力,体外可有效清除H2O2与羟基自由基,并且具有良好的生物相容性;②与对照组比较,H2O2组细胞凋亡率、细胞活性氧与丙二醛水平升高(P<0.05),细胞铺展面积减少(P<0.05),胶原纤维Ⅰ蛋白表达无明显变化(P>0.05);与H2O2组比较,CMC-OCS组、CMC-OCS/PRP组细胞活性氧水平降低(P<0.05),PRP组、CMC-OCS组、CMCOCS/PRP组丙二醛水平降低(P<0.05)、细胞铺展面积增加(P<0.05),CMC-OCS/PRP组细胞凋亡率降低(P<0.05),PRP组、CMC-OCS组、CMCOCS/PRP组胶原纤维Ⅰ蛋白表达增加(P<0.05);③与对照组比较,H2O2组细胞迁移数量减少(P<0.05),迁移面积无明显变化(P>0.05);与H2O2组比较,PRP组、CMC-OCS组、CMC-OCS/PRP组细胞迁移数量、迁移面积均增加(P<0.05),并且以CMC-OCS/PRP组增加最显著;④在氧化应激条件下,CMC-OCS/PRP水凝胶可改善成纤维细胞的迁移能力,抗细胞凋亡并保护细胞伸展功能。

Multi-terminal pectin/chitosan hybrid electrolyte gated oxide neuromorphic transistor with multi-mode cognitive activities

In order to fulfill the urgent requirements of functional products,circuit integration of different functional devices are commonly utilized.Thus,issues including production cycle,cost,and circuit crosstalk will get serious.Neuromorphic computing aims to break through the bottle neck of von Neumann architectures.Electronic devices with multi-operation modes,especially neuromorphic devices with multi-mode cognitive activities,would provide interesting solutions.Here,pectin/chitosan hybrid electrolyte gated oxide neuromorphic transistor was fabricated.With extremely strong proton related interfacial electric-double-layer coupling,the device can operate at low voltage of below 1 V.The device can also operate at multi-operation mode,including bottom gate mode,coplanar gate and pseudo-diode mode.Interestingly,the artificial synapse can work at low voltage of only 1 mV,exhibiting extremely low energy consumption of~7.8 fJ,good signal-to-noise ratio of~229.6 and sensitivity of~23.6 dB.Both inhibitory and excitatory synaptic responses were mimicked on the pseudo-diode,demonstrating spike rate dependent plasticity activities.Remarkably,a linear classifier is proposed on the oxide neuromorphic transistor under synaptic metaplasticity mechanism.These results suggest great potentials of the oxide neuromorphic devices with multi-mode cognitive activities in neuromorphic platform.

Chitosan as green kinetic inhibitors for gas hydrate formation

The kinetic inhibiting effect of a number of chitosans on hydrate formation was investigated using methane and methane/ethane gas mixtures.The results indicated that chitosan was a good kinetic inhibitor.The induction time of gas hydrate formation evidently increased with the degree of deacetylation （DD）,however,when DD was higher than 80%,the effect of DD on the induction time was negligible.Moreover,it was found that the molecular weight （MW） of chitosan and the addition of polyethylene oxide （PEO） had little effect on the induction time.The optimal concentration of chitosan was found to be 0.6 wt%.Finally,the mechanisms of the kinetic inhibitor on the hydrate formation were discussed.

Preparation of Two Different Serials of Chitosan

Two parts of research work on preparation of chitosan are presented. One is about the optimization of preparation condition and the other about the preparation of two series of chitosan with special structures. The first series has the same degree of deacetylation but different molecular weights; and the second the same molecular weight but different in degree of deacetylation.

Specific Targeting MRI of Chitosan Oligosaccharide Modified Fe_(3)O_(4) Nanoprobe on Macrophage and the Inhibition of Macrophage Foam­ing Induced by ox-LDL

Atherosclerosis(AS)is a primary cause of morbidity and mortality all over the world.Molecular imaging techniques can enable early localization and diagnosis of atherosclerosis plaques.Recent newly developed chitooligosaccharides(CSO)is considered to be capable of target mannose receptors on the surface of macrophages and to inhibit foam cell formation.Here we present a targeting magnetic resonance imaging(MRI)nanoprobe,which was successfully constructed with polyacrylic acid(PAA)modified nanometer iron oxide(Fe_(3)O_(4))as the core,and coating with CSO molecules,possessing the abilities of targeted MRI and specifically inhibition of the formation of foamy macrophages in the atherosclerotic process.The experimental results showed that the distributions of PAA-Fe_(3)O_(4) and CSO-PAA-Fe_(3)O_(4) were uniform and the corresponding sizes were about 5.93 nm and 8.15 nm,respectively.The Fourier transform infrared spectra(FTIR)testified the CSO was coupled with PAA-Fe_(3)O_(4) successfully.After coupled with CSO,the r1 of PAA-Fe_(3)O_(4) was increased from 5.317 mM s-1 to 6.147 mM s-1,indicating their potential as MRI contrast agent.Oil Red O staining and total cholesterols(TC)determination showed that CSO-PAA-Fe_(3)O_(4) could significantly inhibit the foaming process of RAW264.7 cells induced by oxidatively modified low density lipoprotein(ox-LDL).In vitro cellular MRI displayed that,compared with PAA-Fe_(3)O_(4),CSO-PAA-Fe_(3)O_(4) could lower the T1 relaxation time of RAW264.7 cells better.In summary,construction of CSO-PAA-Fe_(3)O_(4) nanoprobe in this study could realize the targeted MRI of macrophages and inhibition of ox-LDL induced macrophage foaming process.This will provide a new avenue in the diagnosis and treatment of AS.

Laser-assisted synthesis of Au NPs on MgO/chitosan:Applications in electrochemical hydrogen storage

Hydrogen with high energy density is an environmental alternative to fossil fuels which can respond to the demand for energy considering environmental conditions.It can be stored on porous materials employing physical interaction(e.g.adsorption process).The H2storage capacity of materials can be evaluated through electrochemical methods.Therefore,a fast and straightforward approach was employed to fabricate magnesium oxide/chitosan/Au nanoparticles(Mg O/CS/Au)nanocomposites with porous structure for electrochemical hydrogen storage.Herein,laser ablation in water as a fast and green method was utilized to obtain Au nanoparticles(Au NPs).The obtained Au NPs were loaded on Mg O/CS nanocomposite through physical mixing.Structural and morphological investigation of nanocomposites display spherically shaped Au NPs with a diameter of 49–58 nm agglomerated on the Mg O/CS.Drop casting,the fast and cost-effective method was deployed to deposit the benign,and reusable Mg O/CS/Au-x(x is Au NPs weight percentage of 1,3 and 5 wt.%)nanocomposites on stainless steel mesh and their electrochemical hydrogen storage were measured by cyclic voltammetry(CV),indicating good stability and significant hydrogen storage capacity(28 C/g)after 300 CV scans for MgO/CS/Au-1 sample.