Preparation of Styrenated Phenol Over SO2-4/ZrO2 Catalyst in a Large-Scale Synthesis Process.

Styrenated phenols (SPs) are usually synthesized by the reaction of styrene and phenol under acid catalysts. SPs with a high content of di-styrenated phenol (DSP) can be used to prepare styrenated phenol alkoxylate (SP-A). Therefore, in this study, a scale-up process for synthesizing SPs with high DSP content which can be used for synthesis of SP-A was studied. The solid catalyst used in this study was prepared by impregnation method. SO2-4 was impregnated on a SO2-4/ZrO2 catalyst in an aqueous 1 M H2SO4 solution. The prepared catalysts were characterized by NH3-TPD. Catalytic activity was examined by measuring the conversion of phenol and styrene in a liquid-phase batch reactor. Almost 100% conversion of both phenol and styrene over 5-SO2-4/ZrO2 catalyst was obtained at a reaction temperature of 80 °C and a reaction time of 6 h. The amount of catalyst to the reactants was 2 wt%. Under the same reaction conditions, the selectivity of MSP, DSP, and TSP was 12.4%, 64.5%, and 23.1% respectively.

A Synthesis of Alkoxylates from Styrenated Phenols and Ethylene Carbonate Over KOH/La2O3 Catalysts.

Styrenated phenol alkoxylates (SP-A) are prepared from styrenated phenols (SP) and ethylene oxide (EO) under a homogeneous base catalyst. However, to use EO that is difficult to handle, a high-pressure reaction device capable of reaction process control should be used. Additionally, the homogeneous base catalyst requires a neutralization process to remove the remaining catalyst after the reaction, and it is difficult to separate the catalysts and the product. Therefore, in this study, the separation of product and catalyst by using KOH/La2O3 catalyst was facilitated in the production of SP-A. Also, it was possible to produce SP-A under atmospheric pressure reaction conditions using EC. The mean molecular weight of SP-A varied depending on the reaction conditions, and the size of the mean molecular weight could be arbitrarily controlled by changing the reaction conditions.

A Study on Synthesis of Styrenated Phenol Over Al · Ni/SiO2-Supported Catalysts.

Styrenated phenol was prepared by an alkylation of phenol using NiCl2 and AlCl3 supported on silica gel. The conversion of phenol and styrene of alkylation reaction, and the selectivity of styrenated phenol were investigated. The Al · Ni/SiO2 Supported catalyst was used, the conversion of phenol was almost 100%. The product was in the form of a mixture of mono-styrenated phenol, di-styrenated phenol and tri-styrenated phenol. The styrenated phenol were selectivity of the varies depending on the reaction conditions.

Precipitation of Nickel Oxide on TiO2 Photocatalysts for Enhanced Visible Degradation Activity.

The liquid phase plasma (LPP) synthetic process has been exploited to synthesize nickel oxide nanoparticles doped TiO2 photocatalyst (NOTP) that can respond to visible light. The physicochemical properties of NOTPs were studied by several analysis instruments. The nickel oxide nanoparticles precipitated uniformly on the TiO2 powder are mostly NiO. The band gap energy of the NOTP measured was 2.99 eV, which was smaller than that of bare TiO2, 3.12 eV. The NOTP synthesized in this work showed high photoactivity under visible blue light.

A Study on H2SO4-Treated MxOy Catalysts for Styrenated Phenols by Alkylation of Phenol with Styrene.

Styrenated phenols (SPs) involving very small amount of unreacted phenol and high content of di-SP (DSP) were synthesized, which can be used to prepare SP alkoxylate. The solid catalyst was prepared by impregnation method. SO2-4 on SO2-4/MxOy catalyst was introduced from an aqueous 1M-H2SO4 solution. The catalysts were characterized by XRD patterns, and FT-IR spectra. The catalytic activity was examined by measuring conversion of phenol and styrene in a batch liquid-phase reactor. The concentration of phenol, styrene, and SPs were measured by GC with capillary column. The optimum synthesis conditions for concentration of sulfuric acid solution, catalyst amount of reactants, reaction temperature, and reaction time over SO2-4/ZrO2 catalyst were 15 wt%, 15 wt%, 100 °C, and 6 hr, respectively. At these conditions, conversion of both phenol and styrene were almost 100%, and the selectivity of DSP was 52.1%. On the other hand, the optimum synthesis conditions over SO2-4/TiO2 catalyst were 10 wt%, 5 wt%, 100 °C, and 1 hr, respectively, and conversion of both phenol and styrene were almost 100%, and the selectivity of DSP was 66.1%.

Facile Synthesis and Characterization of Zinc Oxide Nanoparticle on Activated Carbon Using Liquid Phase Plasma Method.

Zinc oxide/activated carbon nanocomposites were synthesized by impregnating zinc oxide nanoparticles onto activated carbon powder using liquid phase plasma (LPP) method. Zinc oxide nanoparticles on the surface of activated carbon were fabricated rapidly by the LPP method due to reducing the zinc ion in aqueous solution. The obtained zinc oxide/activated carbon nanocomposites were characterized by XPS, HRTEM, and EDS. The amount of zinc oxide nanoparticles impregnated increased with increasing initial precursor concentration. Approximately 150~300 nm sized spherical shaped nanoparticles were uniformly dispersed on the surface of activated carbon powder.

Effect of Gold Nanoparticles Addition to CuO­ZnO/A2O3 Catalyst in Conversion of Carbon Dioxide to Methanol.

Hydrogenation of carbon dioxide (CO2) into methanol (CH3OH) was carried out in the CuO­ZnO based supported gold catalyst prepared by the co-precipitation method. When gold nanoparticles were added to the CuO­ZnO/Al2O3 catalysts (CuO­ZnO/Au/Al2O3), the CO2 conversion and CH3OH yield were increased (two times higher than that of CuO­ZnO/Al2O3 catalyst) with increasing reaction pressure, but selectivity of CH3OH was decreased. The main reason of this result could suggest the importance gold-oxides interface in CH3OH formation through hydrogenation of CO2. Maximum selectivity and yield to CH3OH over CuO­ZnO/Au/Al2O3 were obtained at 250°C and under 15­20 bars.

Preparation of Styrenated Phenol by Alkylation of Phenol with Styrene Over SO4²â» /ZrO2 Catalyst.

Styrenated phenols are usually synthesized by the reaction of styrene and phenol under acid catalysts. Styrenated phenol involving high content of di-styrenated phenol (DSP) was synthesized, which can be used to prepare styrenated phenol alkoxylate. The solid catalyst used in this study was prepared by impregnation method. SO4 2- on SO4 2-/ZrO2 catalyst was introduced from an aqueous 1M-H2SO4 solution. The catalysts were characterized by SEM images, XRD patterns, and FT-IR spectra. The catalytic activity was examined by measuring the conversion of phenol and styrene in a liquid-phase batch reactor. Almost 100% conversion of both phenol and styrene over 15-SO4 2-/ZrO2 catalyst were obtained at reaction temperature of 100 °C and reaction time of 6 hr. Amount of catalyst to the reactants was 15 wt%. At same reaction conditions, selectivity of MSP, DSP, and TSP were 23.6%, 52.1%, and 5.4%, respectively. It was known that the selectivity to DSP was increased as IR absorption peak of 1236 cm-1 corresponding to O­S­O bonds was increased.

Bimetallic Pt-Au Nanocatalysts on ZnO/Al2O3/Monolith for Air Pollution Control.

The catalytic activity of a monolithic catalyst with nanosized Pt and Au particles on ZnO/Al2O3 (Pt-Au/ZnO/Al2O3/M) prepared by a wash-coat method was examined, specifically for toluene oxidation. Scanning electron microscopy image showed clearly the formation of a ZnO/Al2O3 layer on the monolith. Nanosized Pt-Au particles on ZnO/Al2O3/M with different sizes could be found in the Pt-Au/ZnO/Al2O3/M catalyst. The conversion of toluene decreased with increasing toluene concentration and was also largely affected by the feed flow rate. The Pt-Au/ZnO/Al2O3/M catalysts prepared in this work have almost the same activity (molecules of toluene per second) compared with a powder Pt-Au/ZnO/Al2O3 catalyst with the same loadings of Pt and Au components; thus this catalyst could be used in controlling air pollution with very low concentrations and high flow rate.

The Characteristics of an Antibacterial TiAgN Thin Film Coated by Physical Vapor Deposition Technique.

In this work, we found the characteristics of an antibacterial TiAgN thin film coated on the pure titanium specimen via the physical vapor deposition process (PVD). TiAgN thin films were coated using TiAg alloy targets by arc ion plating method. Changing the process parameters, the surface analysis of TiAgN thin film was observed by FE-SEM and the force of adhesion was measured with Scratch Tester. The proliferation of human gingival fibroblast (HGF) cells was examined by XTT test assay and the antibacterial properties were investigated by culturing Streptococus Mutans (KCTC 3065) using paper disk techniques. At the result of experiment, cytotoxic effects were not found and the antibacterial effects against Streptococus Mutans were appeared over 5 wt% TiAgN specimens.

Investigation on Sized-Regulated Iron Nanoparticles Prepared by Liquid Phase Plasma Reduction Process.

The liquid-phase plasma reduction method has been applied to prepare iron nanoparticles from iron chloride solution using a bipolar pulsed electrical discharge system. The excited states of atomic iron, hydrogen, and oxygen as well as the molecular bands of hydroxyl radicals were detected in the emission spectra. The iron nanoclusters formed at the initial stage convert to dispersion of small iron nanoparticles, which then grows slowly to form anisotropic, tetragonal shape. The cationic surfactant of CTAB was shown to exhibit a large influence on the particle generation procedure.

Nanosized CuO and ZnO Catalyst Supported on Honeycomb-Typed Monolith for Hydrogenation of Carbon Dioxide to Methyl Alcohol.

The greenhouse effect of carbon dioxide (CO2) has been recognized as one of the most serious problems in the world. Conversion of CO2 to methyl alcohol (CH3OH) was studied using catalytic chemical methods. Honeycomb-typed monolith used as catalyst support was 400 cell/inch2. Pretreatment of the monolith surface was carried out by thermal treatment and acid treatment. Monolith-supported nanosized CuO-ZnO catalysts were prepared by wash-coat method. The prepared catalysts were characterized by using SEM, TEM, and XRD. The catalytic activity for CO2 hydrogenation to CH3OH was investigated using a flow-type reactor with varying reaction temperature, reaction pressure and contact time. Conversion of CO2 was increased with increasing reaction temperature, but selectivity to CH3OH was decreased. Optimum reaction temperature was about 250 degrees C under 20 atm. Because of the reverse water gas shift reaction.

A synthetic study and characterization of the Pt(II) complexes with bipyridines back-born system.

The reaction of platinum [Pt(5,5-dmbpy)]Cl2 (5,5-dmbpy = 5,5'-dimethyl-2,2'-bipyridine) with 4,4'-dimethyl-2,2'-bipyridine (4,4-dmbpy), [Pt(dbbpy)]Cl2 (dbbpy = 4,4'-dibutyl-2,2'-bipyridine), [Pt(dpbpy)]Cl2 (dpbpy = 4,4'-dipentyl-2,2'-bipyridine) with 5,5'-dimethyl-2,2'-bipyridine (5,5-dmbpy) affords the following complexes: [(4,4-dmbpy)Pt(5,5-dmbpy)][PF6]2 (1) and [(dbbpy)Pt(5,5-dmbpy)][PF6]2 (2), [(dpbpy)Pt(5,5-dmbpy)][PF6]2 (3), [(5,5-dmbpy)Pt(5,5-dmbpy)][PF6]2 (4). This study was synthesized new platinum complex compounds utilizing ligand of 5,5'-Dimethyl-2,2'-dipyridyl System. To study the chemical composition was used 1H(13C)-NMR, UV-vis, Spectro photometer and Measurements about optical physics and chemical properties were measured to use spectrofluorometer. UV-vis absorption area was measured 310 nm to 383 nm and luminous wavelength was measured 390 nm to 419 nm.

Junctionless Negative-Differential-Resistance Device Using 2D Van-Der-Waals Layered Materials for Ternary Parallel Computing.

Negative-differential-resistance (NDR) devices offer a promising pathway for developing future computing technologies characterized by exceptionally low energy consumption, especially multivalued logic computing. Nevertheless, conventional approaches aimed at attaining the NDR phenomenon involve intricate junction configurations and/or external doping processes in the channel region, impeding the progress of NDR devices to the circuit and system levels. Here, an NDR device is presented that incorporates a channel without junctions. The NDR phenomenon is achieved by introducing a metal-insulator-semiconductor capacitor to a portion of the channel area. This approach establishes partial potential barrier and well that effectively restrict the movement of hole and electron carriers within specific voltage ranges. Consequently, this facilitates the implementation of both a ternary inverter and a ternary static-random-access-memory, which are essential components in the development of multivalued logic computing technology.

Nanosized CuO and ZnO catalyst supported on titanium chip for conversion of carbon dioxide to methyl alcohol.

In order to reutilize spent metallic titanium chips (TC) as catalyst support or photocatalytic materials, the surface of the TC was modified by thermal treatment under air atmosphere. TC-supported nanosized CuO and ZnO catalysts were prepared by impregnation (IMP) and co-precipitation (CP) method, respectively. The catalytic activity for CO2 hydrogenation to CH3OH was investigated using a flow-typed reactor under various reaction pressures. The crystals of CuO and ZnO was well formed on TC. CO2 conversion, CH3OH selectivity, and CH3OH yield were obtained as a function of time on stream over CuO-ZnO/TC catalysts. Conversion of CO2 to CH3OH over CuO-ZnO/TC catalyst by CP method and CuO/ZnO/TC catalyst by IMP method were ca. 16% and ca. 12%, respectively. Conversion of CO2 over CuO-ZnO/TC catalyst by CP method was increased with increasing reaction temperature in the range of 15-30 atm. Maximum selectivity and yield to CH3OH over CuO-ZnO/TC at 250 degrees C were ca. 90% at 20 atm and ca. 18.2% at 30 atm, respectively.

Bipolar pulsed electrical discharge for decomposition of methylene blue in aqueous TiO2 nanoparticle dispersions.

The objective of this paper is to investigate the decomposition process of organic pollutants by liquid phase plasma. A bipolar pulsed power supply was used to generate discharges in the aqueous TiO2 nanoparticle dispersions. The applied voltage, pulse width, and frequency were 250 V, 5 micros, and 30 kHz, respectively. Properties of generated plasma were investigated by electrical and optical emission spectroscopy methods. The comparison of properties of the discharge operated with and without oxygen gas bubbling is shown. The results of electrical-discharge degradation of methylene blue showed that the decomposition rate increased with the TiO2 particle dosages. Addition of oxygen gas bubbles also increased the degradation rate of methylene blue.

The synthesis of nickel nanoparticles by liquid phase plasma processing.

In this work, the liquid phase plasma reduction method was applied to prepare the spherical nickel nanoparticles from the solution of nickel chloride. A bipolar pulsed power supply was used to generate discharges in the aqueous solutions. Nickel nanoparticle peaks produced by surface plasmon absorption were observed around 381 nm with electrical discharge. Spherical nickel nanoparticles were mostly observed in this study, pentagonal nanoparticles were also observed occasionally. The TEM image showed that the average particle size varied from 10 to 200 nm in diameter as discharge time was increased. Many spots could be seen in the ED pattern for polycrystalline particles.

Photocatalytic degradation of methylene blue over nanosized TiO2 particles prepared using the self-propagating high-temperature synthesis method.

In order to reutilize the spent metallic titanium chips, TiO2 photocatalysts were prepared using the self-propagating high-temperature synthesis (SHS) method, and were characterized by N2 gas adsorption, X-ray diffraction, and scanning electron microscope, particle size distribution. Also, their photocatalytic activities were evaluated using methylene blue as a model organic compound. It was confirmed that the crystal structure of TiO2 prepared by SHS method was relatively homogeneous powder of rutile type. Optimum conditions for photocatalytic degradation of methylene blue under UV-C irradiation were methylene blue 9.5 ppm in solution and at amount of TiO2 added of 0.02 g/L. In addition, it was found that the photocatalytic activity for methylene blue degradation over the prepared TiO2 particles was positively related with BET specific surface area.

Synthesis and properties of the diruthenium(II) complexes with diimine-linked polypyridine bridges.

The diruthenium complexes, [(bpy)2Ru(II)-(bpy-DPDA)-Ru(II)(bpy)2][PF6]4 3, (bpy: 2,2'-bipyridiyl; bpy-DPDA: Bis(2,2'-dipyridylketenylidene)-N,N-1,4-phenylenediamine}, and [(bpy)2Ru(II)-(Dbpy-DPDA)-Ru(II)(bpy)2][PF6]4 4 {Dbpy-DPDA: Bis(2,2'-dipyridyl ketenylidene)-N,N-1,1'-(4,4'-diphenylene)diamine}, were prepared by the reaction of (bpy)2Ru(II)Cl2 with diimine-linked polypyridine bridges. These complexes were characterized by NMR, IR, UV/VIS, PL and cyclic voltammetry. In the 13C-NMR spectra of 3 and 4, the carbon peaks of the Schiff Bases (>C=N-) were shifted to lower fields, and emissions were observed at 689 and 693 nm with quantum yields of 0.004 and 0.006, respectively. The electrochemistry of complexes 3 and 4 showed four-reversible waves (one oxidation wave and three reduction waves). The electrochemically measured band gaps for complexes 3 and 4 were 2.01 and 2.10 eV, respectively.

High-Efficiency WSe2 Photovoltaic Devices with Electron-Selective Contacts.

A rapid surge in global energy consumption has led to a greater demand for renewable energy to overcome energy resource limitations and environmental problems. Recently, a number of van der Waals materials have been highlighted as efficient absorbers for very thin and highly efficient photovoltaic (PV) devices. Despite the predicted potential, achieving power conversion efficiencies (PCEs) above 5% in PV devices based on van der Waals materials has been challenging. Here, we demonstrate a vertical WSe2 PV device with a high PCE of 5.44% under one-sun AM1.5G illumination. We reveal the multifunctional nature of a tungsten oxide layer, which promotes a stronger internal electric field by overcoming limitations imposed by the Fermi-level pinning at WSe2 interfaces and acts as an electron-selective contact in combination with monolayer graphene. Together with the developed bottom contact scheme, this simple yet effective contact engineering method improves the PCE by more than five times.