Search

For diamond/metal composite fabrication, coating diamond particles with metal carbide provides improved wettability between the diamond particles and the matrix. In this study, diamond particles were coated with chromium (Cr) using a molten salt method. Diamond and Cr powders were heated at 600–950 °C in molten salts of lithium chloride (LiCl), potassium chloride (KCl), and sodium chloride (NaCl) to create a chromium carbide (here Cr7C3) coating on the diamond particles. Carbide formation was influenced by the diffusion rate and eutectic point of the molten salt mixture. The resulting Cr7C3 coating surface and microstructure were characterized by X-ray diffraction and scanning electron microscopy, respectively. Coating layer thickness was determined using particle size analysis and confirmed by energy dispersive spectroscopy results. A uniform Cr7C3 layer formed on the surface of the diamond particles at a relatively low temperature, at which the graphitization of diamond is avoided. Compared with a mixture of LiCl, KCl, and calcium chloride (CaCl2), which had been used in our previous study, the LiCl–KCl–NaCl mixture increased the reaction rate and initiated coating at a much lower temperature. The differences between the two molten salt mixtures for coating diamond are discussed in terms of the diffusion parameters.

For diamond/metal composites it is better to use diamond particles coated with metal carbide because of improved wettability between the diamond particles and the matrix. In this study, the coating of diamond particles with a chromium carbide layer is investigated. On heating diamond and chromium powders at 800~900 oC in molten salts of LiCl, KCl, CaCl2, the diamond particles are coated with Cr7C3. The surfaces of the diamond powders are analyzed using X-ray diffraction and scanning electron microscopy. The average thickness of the Cr7C3 coating layers is calculated from the result of the particle size analysis. By using the molten salt method, the Cr7C3 coating layer is uniformly formed on the diamond particles at a relatively low temperature at which the graphitization of the diamond particles is avoided. Treatment temperatures are lower than those in the previously proposed methods. The coated layer is thickened with an increase in heating temperature up to 900 oC. The coating reaction of the diamond particles with chromium carbide is much more rapid in LiCl-KCl-CaCl2 molten salts than with the molten salts of KCl-CaCl2.

Two easily accessible fluorene-based conjugated oligo-electrolytes (COEs) FTF- and FBF-NBr have been developed as the cathode interfacial layer (CIL) in inverted type polymer solar cells (iPSCs). C...

A non-conjugated polyelectrolyte, poly(4-vinyl N-ethyl pyridinium bromide) (PVPy-EtBr), is applied to polymer solar cells (PSCs) as a cathode buffer layer either inverted or conventional type polym...

As a part of the study on recycling Li(NCM)O2lithium-ion battery scraps, solvent extraction experiments were performed using different extraction agents such as PC88A, Cyanex272 and D2EHPA to separate Co, Ni and Mn from the leaching solution. When the ratio of Mn to Ni was about 0.4 in the leaching solution, the separation factor for Co and Mn was found to be less than 10 so that the separation of Co and Ni was insufficient. When solvent extraction was done using the solution with the lower Mn/Ni ratio of 0.05 where Mn was removed by potassium permanganate and chlorine dioxide, more than 99% of Mn could be extracted through five courses of extraction using 30vol% D2EHPA while the extraction rates of Co and Ni were around 17% and 11%, respectively. In the case that Mn was removed from the solution, the extraction rate of Co was higher than 99% whereas less than 7% Ni was extracted using Cyanex272 suggesting that Co and Ni elements were effectively separated.

A series of small-molecules (SMs) based on coplanar perylene unit coupled with diketopyrrolopyrrole chromophoric core exhibit broad absorption in the range of 500–800 nm and low bandgap energise of...

In this study, catalytic activity and thermal stability of the arc plasma deposited (APD) Pt nano-particles on A12O3 and CeO2-Al2O3 were compared with that of the conventionally prepared Pt/Al2O3. All the catalysts were characterized by BET-surface area, transmission electron microscopy, X-ray photoelectron spectroscopy, CO-pulse chemisorption, H2-temperarture programmed reduction and X-ray absorption near edge spectroscopy. Through the quantum chemical calculations of different metal oxide support, CeO2 was identified as a suitable anchoring material with high energy level between the Pt species (Pt(0) and PtO(x)) on ceria. Subsequently, the results of XPS and XANES revealed the presence of abundant Pt(0) metal species in APD catalysts. The addition of ceria to Al2O3 support enhanced the dispersion of Pt nano-particles. The H2-TPR of Pt/CeO2-Al2O3 (APD) catalyst showed high-temperature reduction peaks corresponding to the interaction of Pt with ceria on alumina by Pt-O-Ce. Consequently, the Pt nano-particles deposited on CeO2-Al2O3 by APD attained strong thermal resistance at high temperatures. In addition, superior catalytic activities for CO and C3H6 oxidation and NO(x) reduction were obtained for the Pt/CeO2- Al2O3 (APD) catalyst.

battery, which operates as the same mechanism of battery using solid-electrolyte, is able to reduce its material cost by 40 % comparing to the battery. It has been known that the battery produces as an intermediate phase during charge/discharge process. Therefore, the redox process is divided into four steps having the voltage range of 1.92~2.13 V. However, effects of the critical factors such as the composition of cathode materials, depth of charge and discharge, and additives have not been reported yet. We examined the effect of the Zn/NaCl ratios and revealed that its optimum ratio was in the range of 1.3~1.7.

Microwave assisted sol–gel method is used to fabricate nanostructured Li2MnSiO4/C composites. Our process has the advantages in homogenous heating and reduced reaction time. In addition, the water is used as a base solvent while the conventional microwave-solvothermal method use the organic solvent as the base solvent, which makes our process much more safe and economical. Here, our prepared Li2MnSiO4/C composite exhibits an enhanced discharge capacity of 173.1 mAh g−1, compared to the conventional processes.

Zinc oxide (ZnO) thin films have been grown by using atomic layer deposition (ALD) on O2-plasma-treated polyethersulfone (PES) substrates. We investigated the effects of the duration of O2 plasma pretreatment from 0 to 60 min on the characteristics of ZnO thin films grown on the substrates. When the duration of the plasma treatment increases, the surface roughness of the PES substrate increases. X-ray diffraction (XRD) measurements reveal an increasing tendency toward preferential c-axis orientation of the grains in the ZnO thin films with increasing duration of plasma pretreatment, which probably results from the improved crystallinity of the ZnO thin films grown on the roughened PES substrates after O2 plasma pretreatment. The roughened surfaces of PES substrates promote many nucleation sites, leading to perpendicular c-axis growth of ZnO thin films and, therefore, improved crystallinity of the ZnO thin films. The peak intensity of the NBE emission around 3.0 eV decreases with increasing duration of O2 plasma pretreatment up to 30 min. Then, it rapidly increases up to 60 min. The variations of the PL intensity and the NBE peak position strongly depend on the crystallinity of the ZnO thin films.

Zinc oxide (ZnO) nanorods were grown on polyethersulfone substrates with a seed layer by hydrothermal synthesis. The effects of the growth temperature and duration on the structural and optical properties of the ZnO nanorods were investigated by X-ray diffraction, field emission scanning electron microscope and photoluminescence measurements. Improvement of the structural properties was confirmed when the ZnO nanorods were grown at a moderate thermal energy. Thermal energies that were too high or too low resulted in structural degradation: low thermal energies did not provide enough energy for the ZnO growth, and high thermal energies contributed to improper growth by creating an uncommon flake-like structure. Photoluminescence measurements showed that the near-band-edge emission to deep-level emission peak ratio increases with increasing growth temperature at growth duration of 5 h.

The influence of sulfate on the selective catalytic reduction of on the Ag/ catalyst was studied when was used as a reducing agent. Various preparation methods influenced differently on the activity. Among the methods, cogelation precipitation gave best activity. When sulfates were formed on the surfaces of samples prepared by impregnated and deposition precipitation, activity was enhanced as long as suitable forming condition is satisfied. The major sulfate formed in Ag/ catalyst was the aluminum sulfate and it seems that this sulfate acted as a promoter. When Mg was added to the Ag/ catalyst it promoted activity at high temperature. Intentionally added sulfate also enhanced activity, when their amount was confined less than 3 wt%.

New low-band-gap copolymers, including thieno[3,2-b]thiophene and 2,1,3-benzothiadiazole, were synthesized as photovoltaic materials. Thiophene was introduced to provide extended π-conjugation length and charge transfer properties. A band gap ( E g op =1.62 eV, E g ec =1.51 eV) of this polymer was investigated through UV–vis spectroscopy and cyclic voltammetry. A bulk heterojunction structure of glass/indium tin oxide (ITO)/PEDOT:PSS/polymer-PCBM(1:3)/LiF/Al was fabricated for investigating photovoltaic properties. PC 71 BM was used as an acceptor material, due to its increased absorption in the visible region, in comparison with PC 61 BM. In this polymer, incident photon-to-current conversion efficiency (IPCE) was as high as 50%. Moreover, maximum power conversion efficiency (PCE) of up to 1.72% was achieved under AM 1.5 G conditions. It demonstrated relatively high V OC (0.67 V) and J SC (6.86 mA/cm 2 ), while a low fill factor value (0.37) was obtained.

Titanium oxalate was precipitated by the addition of TiO(NO3)2 solution to an ethanol solution of oxalic acid and then ripened in the mother solution with/without ultrasound at various temperatures. The influence of various factors such as reaction temperature and ripening time, as well as the effect of ultrasonic treatment in the solution, was investigated. During the ripening reaction of the titanium oxalate, a new crystalline phase was found. The chemical formula and the crystal system of the new phase were as follows: (1) Chemical formula—Ti2O2(C2O4)(OH)2H2O, (2) Crystal system—orthorhombic with lattice constants of a = 1.0503 nm, b = 1.5509 nm, and c = 0.9700 nm. The treatment of ultrasound during the ripening reaction accelerated the dissolution rate of the initial precipitated particles, so that the formation of the crystalline phase was hastened.

A precipitation reaction between a lead-nitrate solution and oxalic acid was carried out with and without ultrasound, and the effect of ultrasonic irradiation in solution was investigated. The oxalate precipitates were a mixture of Pb oxalate and an X-phase, which seems to be a lead salt containing C2O42−NO3−, and OH−. It was found that irradiation with ultrasound during the precipitation reaction accelerated the formation of the X-phase.