Formation of FePt intermetallic compound nanoparticles by plasma-induced cathodic discharge electrolysis

Magnetic nanoparticles of FePt intermetallic compound were formed in molten LiCl-KCl-CsCl electrolyte under 1 atm of Ar atmosphere by plasma-induced cathodic discharge electrolysis. By utilizing the displacement reaction between the Fe(0) and Pt(II), FePt intermetallic compound nanoparticles were obtained from the melt. The displacement reaction produced small primary particles that considerably aggregated to form larger secondary particles. The coercivity of the obtained FePt intermetallic compound nanoparticle increased with a longer residence time in the melt. The coercivity of the FePt intermetallic compound nanoparticle obtained after a residence time of 3 h was measured to be 199 mA m⁻¹. FePt intermetallic compound nanoparticles could also be obtained by the co-depositing Fe and Pt from Fe(II) and Pt(II) in the melt. In this case, the primary particle size distribution became broader, but the aggregation of primary particles was suppressed. The coercivity of the obtained FePt intermetallic compound nanoparticles showed a quite high value of 245 mA m⁻¹ that did not depend on the residence time.     

Polymerisation by glow discharge electrolysis

A glow discharge passed from a metal anode to the surface of aqueous solutions of acrylamide produces radicals which initiate polymerisation. The yield of polymer together with its relative molecular mass has been examined as a function of monomer concentration and pressure in neutral solutions. The form of the variations can be explained in terms of a simplified reaction scheme. On the basis of the proposed mechanism there are two reaction zones. In the primary reaction zone no polymerisation occurs, the radical concentration being too high. About 0·2% of the radicals escape into the secondary reaction zone to initiate polymerisation, the volume of this zone being about 0·4 cm³.In alkaline solutions the yields and relative molecular masses of the polymers are very low and this is attributed to chain termination by oxygen which rises from the destruction of hydrogen peroxide in alkaline solution.     

Synthesis and characterization of superabsorbent composite by using glow discharge electrolysis plasma

A convenient and effective technique for polymerization to produce the poly(acrylic acid-co-acrylamide)/montmorillonite superabsorbent composite in aqueous solution was developed, in which the reaction was initiated by the glow discharge electrolysis (GDE) plasma rather than chemical initiators. The resulted superabsorbent has higher water absorbency, for example, 1024 g g⁻¹ for distilled water and 56 g g⁻¹ for 0.9% NaCl solution. To optimize the synthesis conditions, the following parameters were examined in detail: the discharge voltage, discharge time, ratio of acrylic acid to acrylamide, neutralization of acrylic acid, amount of crosslinking agent and montmorillonite added. The superabsorbent composite was characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Results indicated that montmorillonite was effectively bonded with polymer. Moreover, the water absorbency, water retention and thermal stability of the superabsorbent composite prepared by GDE were higher than those of the superabsorbent composite by conventional chemical method under the same polymerization conditions.     

利用淀粉制备碳保护金属Ni、Co纳米粒子

Carbon-protected metallic nanoparticles（nickel and cobalt）composites were prepared by the pyrolysis of the mixture of soluble starch and metallic acetate in N₂ flow via an easy green synthetic route.The obtained samples were highly stable in air.Reducing agent was not used in the experiments.The as-synthesized samples were characterized by XRD,TEM,and N₂ adsorption-desorption analysis.The results of N₂ adsorption-desorption analysis indicated that the obtained samples possessed mesoporous structures and high BET surface areas.     

A model for glow discharge electrolysis

Two models (a cylinder model and a cone model) are proposed to represent the inhomogeneous distribution of radicals in the liquid phase in glow discharge electrolysis. The models have been applied to polymerization by glow discharge electrolysis and the cone model has some success in accounting for the dependence of the rate of polymerization and the degree of polymerization on the monomer concentration and the pressure in the discharge.     

辉光放电电解降解水体中阳离子桃红FG的机理

用辉光放电电解（GDE）技术对模拟染料废水阳离子桃红FG的降解过程进行了研究。通过发射光谱法测定了GDE产生的活性粒子,用紫外光谱和总有机碳（TOC）分析仪研究了不同放电时间下的脱色率和去除率,用电导率仪和酸度计测定了降解过程中溶液的电导率和pH的变化,同时用离子色谱对降解中间产物进行了分析。结合各种分析结果,探讨了GDE降解阳离子桃红FG的机理。结果表明,在最佳电压600 V时,溶液中产生HO·、O·、H·等高活性粒子;放电120 min时,200 ml 20 mg/L阳离子桃红FG的脱色率和TOC去除率分别可达99.0%和72.6%;降解液pH先减小后增大,电导率存在先增大后减小的趋势;离子色谱测试表明,降解过程中产生多种有机小分子酸。羟基自由基（HO·）对阳离子桃红FG的降解起关键作用,GDE降解阳离子桃红FG的机理为：HO·作用下助色基团键断裂,产生酚类等中间产物,然后继续被降解为醌和小分子有机酸,最终矿化为Cl^-、NO₃^-、CO₂和H₂O。     

Synthesis of Ni nanoparticles with controllable magnetic properties by atmospheric pressure microplasma assisted process

An atmospheric pressure microplasma technique is demonstrated for the gas phase synthesis of Ni nanoparticles by plasma‐assisted nickelocene dissociation at different conditions. The dissociation process and the products are characterized by complementary analytical methods to establish the relationship between operational conditions and product properties. The innovation is to show proof‐of‐principle of a new synthesis route which offers access to less costly and less poisonous reactant, a higher quality product, and a simple, continuous and pre/post treatment‐free manner with chance for fine‐tuning “in‐flight.” Results show that Ni nanoparticles with controllable magnetic properties are obtained, in which flexible adjustment of product properties can be achieved by tuning operational parameters. At the optimized condition only fcc Ni nanoparticles are formed, with saturation magnetization value of 44.4 mAm²/g. The upper limit of production rate for Ni nanoparticles is calculated as 4.65 × 10^?3 g/h using a single plasma jet, but the process can be scaled‐up through a microplasma array design. In addition, possible mechanisms for plasma‐assisted nickelocene dissociation process are discussed. © 2017 The Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers AIChE J, 64: 1540–1549, 2018     

通过电解副产物计算阴极电流效率

指出电解食盐水时可能发生的几种副反应，分析其对电流效率的影响，介绍利用副反应产物计算阴极电流效率的公式及其应用。通过计算，提出要提高电流效率，一方面要提高阳极的析氧过电位，另一方面要提高膜的选择性。     

Preparation of tin-filled carbon nanotubes and nanoparticles by molten salt electrolysis

This article presents a molten salt electrolytic method of synthesizing tin-filled carbon nanostructures, in which a melt of LiCl with an addition of SnCl₂ is electrolyzed between two graphite electrodes. In this process, Li intercalates into the cathodically polarized graphite while Sn is deposited onto the graphite surface. The Li intercalation causes the release of graphitic layers from the graphite, which enclose the Sn deposits, to form Sn-filled MWCNTs and carbon nanoparticles. By reversing the polarity of the graphite electrodes at regular intervals during electrolysis, the process can be extended substantially until the electrodes have been completely consumed, suggesting its suitability for production at a larger scale.     

Synthesis of carbon nanocapsules containing Fe, Ni or Co by arc discharge in aqueous solution

A simple, inexpensive and one-step synthesis method of metal-containing carbon nanocapsules using an arc discharge in aqueous solution is reported. It was found that Ni, Co and Fe nanoparticles could be in situ encapsulated in carbon shells when the arc was performed respectively in aqueous solutions of NiSO₄, CoSO₄ and FeSO₄. Transmission electron microscopy, energy dispersive X-ray spectroscopy and electron diffraction patterns of selected areas were used to determine the crystalline phase of the metal cores. To explain the formation mechanism of metal-containing carbon nanocapsules, a model of discharge in solution is proposed. This result presents a simply controllable way to synthesize metal-containing carbon nanocapsules.     

Facile preparation of Bi nanoparticles by novel cathodic dispersion of bulk bismuth electrodes

A novel electrochemical approach has been developed to prepare clean bismuth nanoparticles (NPs) with a bulk Bi electrode in a 0.5 mol dm⁻³ NaOH solution under highly cathodic polarization of −8 V versus a saturated mercurous sulfate electrode, requiring no any precursor ions and organic protective agents. The bulk Bi electrode can be facilely dispersed into Bi NPs at the condition of intensive hydrogen evolution. This cathodic dispersion of the bulk Bi electrode involves the formation and decomposition of unstable bismuth hydrides and the aggregation of atomic bismuth from the decomposition. Moreover, Bi₂O₃ NPs have also been achieved by heating the precursor Bi NPs. Field-emission scanning electron microscopy, transmission electron microscope and X-ray diffraction were used to characterize these NPs. The as-prepared Bi NPs mainly existed in rhombohedral phase.     

Introduction of functional groups to polyalanine and alanine by contact glow discharge electrolysis

Summary The alanine residue of poly-DL-alanine (DP=120) was converted to Asp, Thr, Ser, Glu and Gly residues by means of contact glow discharge electrolysis (CGDE) in a formic and an acetic acid solution. The total conversion of alanine residues to other amino acid residues was almost 20%.     

Degradation of poly(acrylamide) in aqueous solution by glow discharge electrolysis

Summary The glow discharge electrolysis was carried out to an aqueous solution containing poly(acrylamide). The analytical results of the degradation products showed that the degradation takes place stepwise caused by the cleavages of the main and also the side chains of the polymer.     

Direct current cathodic glow discharge polymerization of methane and butane

The deposition of a polymeric material on the surface of the cathode of a direct current (dc) glow discharge was investigated for methane and butane. The cathode region of a dc glow discharge is not a plasma in a strict sense. Consequently, the deposition of a polymeric material to the cathode surface differs significantly from so-called plasma polymerization of the same monomer (starting gas or vapor) that deposits on a substrate placed in a glow discharge plasma. Using methane and n-butane, the influence of the molecular weight of the monomer (M), volume flow rate, and discharge power on the deposition rate in a dc glow discharge were investigated and compared with those in an audio frequency and a radio frequency glow discharge. It was found that the deposition rate expressed in (thickness growth rate)/(M) is linearly proportional to the current density, which implies that cathodic polymerization is controlled by the cathode region parameter (not plasma parameters). The refractive indices (632.8 nm) for the cathodic polymers are in the range of 2.2–2.4 while those for plasma polymers are in the range of 1.5–1.7. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 237–245, 1998     

成对电解同时合成丁二酸和乙醛酸

研究了成对电解新工艺，即在阳极室乙二醛电氧化合成乙醛酸，收率超过７０％；在阴极室顺丁烯二酸电还原合成丁二酸，收率可达８５％。同一电解槽同时获得二种高附加值的产品，并且比旧工艺节约了４０％的电能。该工艺具有投资少，工艺简单，而且无三废排放的特点     

Formation and size control of titanium particles by cathode discharge electrolysis of molten chloride

Cathode discharge electrolysis of LiCl–KCl–K₂TiF₆ has been conducted under 1 atm of Ar. Near spherical particles consisting of metallic or partially oxidized titanium in the core and TiO₂ in the surface layer were obtained. The Ti particles are originally formed in the melt by reduction of Ti ions, and a surface TiO₂ layer is formed when the Ti particles are exposed to air or water. The particle sizes were in the range 10–400 nm, and were strongly dependent on electrolytic conditions, such as quantity of electricity, K₂TiF₆ concentration, bath temperature and current per melt volume. The particle growth mechanism was also investigated, and it was confirmed that reduction of ions at particle surfaces is involved in particle growth.     

Modification of polyolefin surfaces by plasma-induced grafting

Polar monomers have been grafted onto polyolefin surfaces with the aid of inert gas plasma. In the first stage, an inert gas plasma (argon plasma) was used to generate free radicals on the polyolefin surface. In the second stage, the plasma generator was turned off and a vinyl monomer introduced as a vapor. Monomer was surface grafted by free radical polymerization. After cleaning and drying, the samples were analyzed by XPS, IR, and contact angle. LD–PE was successfully grafted with acrylic acid, glycidyl methacrylate, methyl acrylate, and 2-hydroxy ethylacrylate. The grafting of acrylic acid was studied in more detail, and the rate of grafting was observed to increase with increasing monomer pressure and to decrease with time. The increasing of grafting temperature was found to reduce the degree of grafting. This last factor can be explained by the reduced concentration of monomer at the polymer surface or by a deactivation of surface radicals. © 1996 John Wiley & Sons, Inc.     

Synthesis of single-wall carbon nanotubes and long nanotube ribbons with Ho/Ni as catalyst by arc discharge

The effect of a new bimetallic catalyst Ho/Ni for synthesis of single-walled carbon nanotubes (SWNTs) by arc discharge has been studied. Long ribbons consisting of roughly-aligned SWNT bundles were obtained by a modified arc discharge apparatus. Ribbon lengths can reach as much as 20 cm. Both elements Ho and Ni play important roles in the synthesis of SWNTs with high yield and purity. Changes in the Ho and Ni concentration in the catalyst hardly affect the diameter distribution of SWNTs, but the yield and purity of SWNTs are very sensitive to the concentration. An optimal range of Ho/Ni compositions for synthesis of SWNTs with relatively high purity and yield is given.     

Electrocatalytic and thermal activation of anodic oxygen- and cathodic hydrogen-evolution in alkaline water electrolysis

In micro-electrolysis cells (4 cm² electrode area) which possess a sandwich-configuration as used in advanced water electrolysis[1] different anodic and cathodic electrocatalysts, which did not contain noble metals were investigated over the current density range from 10^?4 to 1.0 A cm^?2 and a temperature range from 30 to 130°C (electrolyte: 50 wt% caustic potash). Mechanically activated nickel electrodes, RuO₂ doped anodes and Pt-black covered cathodes served as comparison standards for H₂ and O₂ evolution.IR-drop connections were not applied. Nonetheless the measuring-method used allowed to keep IR-induced mistakes in voltage-reading in single-electrode voltages below 40 mV even at the highest current densities of 1.0 A cm^?2.Plots of voltage vs log current densities for anodic oxygen evolution possess slopes between 40 and 70 mV (100°C) dec^?1 of current density which in some cases—especially at low temperatures—increased up to a value of 2 RT/F at higher current densities. By increasing the temperature these steeper parts of the anodic current—voltage curves very often disappear.The current-voltage curves of anodic oxygen evolution for different temperatures unexpectedly run nearly parallel to each other ie with a slope which is nearly independent of temperature and thus cannot be described according to the Butler—Volmer equation with a constant value of the formal charge-transfer coefficient βⁱ.The effective activation energies obtained from dln i_o/d(1/T) range from 70 to 100 kJ mole^?1.O₂ overpotentials at current densities around 1 A cm^?2 are most efficiently decreased by (i) application of mixed oxides containing cobalt in at least two different valency states (Co^II/Co^III or Co^III/Co^IV) and (ii) by use of higher working temperatures; roughened surfaces, however, are only of limited value in this respect.Voltage vs log current curves for cathodic hydrogen evolution show a pattern which is in agreement with the Butler—Volmer equation. The effective charge-transfer coefficient is close to 0.5 and increases slightly above this value for Raney-metal activated cathodes.The effective activation energies lie between the limits of 40 and 55 kJ mol^?1. Hydrogen evolution overpotentials are most efficiently decreased by (i) preparation of cathode surfaces with high roughness factors, (ii) using Ni, Co or Fe as cathode material and (iii) by increasing the working temperatures.     

Synthesis,Characterization, and swelling behaviors of acrylic acid/carboxymethyl cellulose superabsorbent hydrogel by glow‐discharge electrolysis plasma

This article exploits a new approach for synthesis of acrylic acid/carboxymethyl cellulose (AA/CMC) superabsorbent hydrogel in aqueous solution by a simple one‐step using glow‐discharge electrolysis plasma, in which N,N′‐methylenebisacrylamide (MBA) was used as a crosslinking agent. The reaction parameters affecting the equilibrium swelling, that is, discharge voltage, discharge time, mass ratio of AA to CMC, content of crosslinker, and degree of neutralization, were systematically optimized to achieve a superabsorbent hydrogel with a maximum equilibrium swelling. The structure, thermal stability, and morphology of AA/CMC superabsorbent hydrogel were characterized by Fourier transform infrared spectroscopy, X‐ray diffraction analysis, thermogravimetric analysis, and scanning electron microscopy. The swelling kinetics in distilled water and swelling behaviors in various pH solutions and salts solutions (NaCl, KCl, MgCl₂, CaCl₂, AlCl₃, and FeCl₃) were investigated in detail. The effect of six cationic salt solutions on the equilibrium swelling had the following order K⁺ > Na⁺ > Mg²⁺ > Ca²⁺ > Al³⁺ > Fe³⁺. In addition, the pH‐reversibility was preliminarily investigated with alternating pH between 6.5 and 2.0. The results showed that the equilibrium swelling of AA/CMC was achieved in 90 min. The hydrogel was responsive to the pH and salts, and was reversible swelling and deswelling behavior. POLYM. ENG. SCI., 54:2310–2320, 2014. © 2013 Society of Plastics Engineers