Liquid Deposition Method Research Articles

Samarium colloids prepared in organic solvents and active solids

Samarium colloids in organic solvents (2-methoxyethanol, 2-propanol, 2-propanone, and 1,2-dimethoxyethane) were obtained by the chemical liquid deposition (CLD) method at 77 K. The colloids were characterized by electron diffraction, energy-dispersive X-ray (EDX), UV-Vis spectroscopy, kinetic stability, and electrophoretic measurements. The colloid stability depends on the solvent used and the metal concentration. The higher stability was obtained in 2-methoxyethanol, which is in agreement with previous results for other lanthanide colloids. The zeta potential (ζ) of the colloids ranges between 0.138 and 1.945 mV. The UV-Vis spectra exhibit bands characteristic of the solvent. The 2-methoxyethanol shows bands at 205 and 234 nm very similar to the 2-propanol which exhibits bands at 202 and 253 nm for 2.5E−4 M concentration. However, bands for 1,2-dimethoxyethane and 2-propanone colloids were impossible to determine due to their highest extinction coefficient values. A dependence of the UV/Vis spectral properties of these new sol materials with Sm(III) is described. In all cases, the EDX analyses confirm the presence of metal in the colloids. The electron diffraction gives the most common (hkl) planes corresponding to Sm and Sm2O3 (211) and (100), respectively. As shown by the particle size distribution determined from transmission electron microscopy (TEM), the Sm-2-methoxyethanol colloids exhibit ranges from 1.6 and 2.9 nm, but the Sm-2-propanol colloids show ranges from 2.3 to 2.5 nm; the medium particle size of Sm-1,2-dimetoxyethane colloid is 0.8 nm, and the Sm-2-propanone colloids have a range from 1.0 and 4.3 nm, exhibiting a solvent polarity dependence. Also, active solids from the evaporation of the colloids which have been fully characterized by several chemical and physical techniques have been obtained.

Fabrication and photoelectrochemical properties of silicon nanowires/g-C3N4 core/shell arrays

A photoelectrochemical (PEC) cell made of metal-free carbon nitride (g-C3N4) @siliconnanowire(Si NW) arrays (denoted as Si NWs/g-C3N4) is presented in this work. The as-prepared photoelectrodes with different mass contents of g-C3N4 have been synthesized via a metal-catalyzed electroless etching (MCEE), liquid atomic layer deposition (LALD) and annealing methods. The amount of g-C3N4 on the Si NW arrays can be controlled by tuning the concentration of the cyanamide solution used in the LALD procedure. The dense and vertically aligned Si NWs/g-C3N4 core/shell nanostructures were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). In comparison with FTO/g-C3N4 and Si NW samples, the Si NWs/g-C3N4 samples showed significantly enhanced photocurrents over the entire potential sweep range. Electrochemical impedance spectroscopy (EIS) was conducted to investigate the properties of the charge transfer process, and the results indicated that the enhanced PEC performance may be due to the increased photo-generated interfacial charge transfer between the Si NWs and g-C3N4. The photocurrent density reached 45μA/cm2 under 100mW/cm2 (AM 1.5G) illumination at 0V (vs. Pt) in neutral Na2SO4 solution (pH∼7.62). Finally, a systematical PEC mechanism of the Si NWs/g-C3N4 was proposed.

Investigation of the anti-adhesion layers for nanoimprint molding

To realize the anti-adhesion issue between silicon mold and nanostructures of hard polydimethylsiloxane (H-PDMS), anti-adhesion layers were coated on molds to improve the H-PDMS grating structure with half-pitch below 200 nm. Various deposition methods such as liquid immersion method, vapor deposition method, and plasma-enhanced chemical vapor deposition were used to coat various anti-adhesion layers, respectively. Three anti-adhesion layers including diamond-like carbon (DLC) film, fluorine-doped diamond-like carbon (F-DLC) film, and perfluorooctyl-trichlorosilane (PFOTCS) were investigated. PFOTCS was functioned as a mold-releasing agent using the liquid immersion and vapor deposition methods, respectively. The effect of those anti-adhesion layers on the molding process was characterized. The results show that the PFOTCS anti-adhesion layer coated by vapor deposition method exhibits the best separability among all of the anti-adhesion layers. The maximum contact angle using PFOTCS is about 115° under 0.5 h of heating time. Compared to DLC, the F-DLC anti-adhesion layer shows good separability when the line width exceeds 100 nm, and does not require recoating again after each use. In addition, atomic force microscopy (AFM) was adopted to measure the adhesion force between the H-PDMS and the anti-adhesion layers.

Anatase TiO2 nanotube arrays and titania films on titanium mesh for photocatalytic NOX removal and water cleaning

An anodization method was developed for the preparation of highly photoactive titania nanotube arrays (TiNTs) on commercially available titanium mesh. The prepared material was characterized from the point of view of its structure and possible photocatalytic applications and was compared with titania films deposited on the Ti-mesh by liquid deposition (TiO2-LD) and sol-gel methods (TiO2-SG). The photoactivity was determined in gas phase using NOX decomposition according to the ISO standard no. 22 197-1 (2007) as well as in liquid phase by decolorization of organic dyes e.g. methylene blue (MB) and rhodamine B (RhB). The investigated anatase nanotube arrays on Ti mesh showed the highest photoactivity in both gaseous and liquid phases and are promising for applications in photocatalytic reactors for environmental purification.

Coating mechanism and near-infrared reflectance property of hollow fly ash bead/TiO2 composite pigment

Nanometer titanium dioxide was deposited on hollow fly ash beads using a chemical liquid deposition method. Surface modification of hollow fly ash beads with Ca(OH)2 saturated solution resulted in the presence of calcium silicate hydrate. The surface modification had a great influence on the growth and micro-morphology of TiO2 nanoparticles on the surfaces of hollow beads. Electrostatic repulsive forces between the modified hollow bead surfaces and hydrated TiO2 were significantly reduced after the surface modification, favoring the formation of a homogeneous and uniform TiO2 film with high TiO2 loading. A possible growth mechanism of TiO2 coatings was proposed. Moreover, the near-infrared solar reflectance of hollow bead/TiO2 composite pigment reached 0.68, which was approximately 1.8 times as high as that of hollow beads. An approximately 28.1°C decrease in temperature was obtained for the inner surface of a calcium silicate board coated with composite pigments. Therefore, hollow fly ash bead/TiO2 composite pigments are excellent candidates for near-infrared reflective pigments used in solar reflective coatings.

Chemical Liquid Deposition Modified ZSM-5 Zeolite for Adsorption Removal of Dimethyl Disulfide

A series of ZSM-5 zeolites were prepared through a chemical liquid deposition (CLD) method and used for adsorption removal of dimethyl disulfide (DMDS) from methyl tert-butyl ether (MTBE). The structural properties and acidity were characterized, and the proper deposition amount and calcination temperature have been accessed. N2 adsorption test and X-ray photoelectron spectroscopy (XPS) results show that methylsilicone oil is deposited on the external surface and narrows the pore size of the zeolite. NH3-temperature-programmed desorption (NH3-TPD) and modified Hammett indicator titration results indicate that the acid sites on the external surface are eliminated while acid sites in the channel are not influenced significantly. Both the pore structure and acidity play important roles in determining the sulfide adsorption process. The optimal modification condition was found as a deposition amount of 30% and a calcination temperature of 500 °C. Adsorption isotherms were also conducted in both parent and CLD...

Bisthiadiazole-Fused Tetraazapentacenequinone: An Air-Stable Solution-Processable n-Type Organic Semiconductor.

The synthesis and characterization of a tetraazapentacenequinone fused to two thiadiazoles is reported. This linear derivative constituting seven fused rings shows a very low LUMO level (-4.46 eV) and a low HOMO-LUMO gap (1.77 eV). Its high solubility, endowed by four triisopropylsilyl groups, allows the fabrication of air-stable field-effect transistors by liquid deposition methods that show electron mobilities up to 2.42 × 10(-3) cm(2) V(-1) s(-1) without any device optimization.

Preparation of MWCNTs/CuPc/Ag modified conductive polyester fiber with chemical liquid deposition

Novel multi-walled carbon nanotubes (MWCNTs) and copper phthalocyanine (CuPc) modified conductive silver-plated fiber (MCA-fiber) was successfully prepared via chemical liquid deposition method with polyester as soft template. The structures and morphologies were characterized by X-ray photoelectron spectroscopy and field emission scanning electron microscopy. The binding energy of oxygen and carbon are 543, 296 eV respectively and the SEM images show CuPc and MWCNTs are deposited on the surface of silvered fiber continuously. The MCA-fiber is about 75 μm in diameter. The effect of process conditions on the properties of MCA-fiber was investigated. With the increasing of the concentration of AgNO3, the coating amount and electrical conductivity first increase and then decrease. The decrease of MWCNTs can bring down the electrical conductivity, but can improve the coating amount of materials on the surface of fibers. There is a sharp decrease from 7.20 × 10−4 to 1.33 × 10−4 s/cm when the MWCNT-doping content is 20 %. When the doping ratio of MWCNTs and CuPc is 2:8, the coating amount rises to 19.2 %. The mechanism study on the photovoltaic properties of MCA-fiber verifies that it can be used in fiber-shaped solar cells.

Production of Light Olefins Through Catalytic Cracking of C5 Raffinate Over Surface-Modified ZSM-5 Catalyst.

Surface modification of phosphorous-containing porous ZSM-5 catalyst (P/C-ZSM5-Sil.(X)) was carried out by a chemical liquid deposition (CLD) method using tetraethyl orthosilicate (TEOS) as a silylation agent. Different amount of TEOS (X = 5, 10, 20, and 30 wt%) was introduced into P/C-ZSM5il.(X) catalysts for surface modification. The catalysts were used for the production of light olefins (ethylene and propylene) through catalytic cracking of C5 raffinate. It was found that external surface acidity of P/C-ZSM5-Sil.(X) catalysts significantly decreased with increasing TEOS content. In the catalytic reaction, both conversion of C5 raffinate and yield for light olefins showed volcano-shaped curves with respect to TEOS content. Among the catalysts tested, P/C-ZSM5-Sil.(20) catalyst exhibited the best catalytic performance in terms of conversion of C5 raffinate and yield for light olefins. Thus, an optimal TEOS content was required for CLD treatment to maximize light olefin production in the catalytic cracking of C5 raffinate over P/C-ZSM5-Sil.(X) catalysts.

Study on Anti-Adhesion Layers Using AFM for Nanoimprint Process

This study investigates how to improve the anti-adhesion issues between Silicon mold and nanostructures of hard polydimethylsiloxane (H-PDMS). A Silicon mold with different depths and widths was made using a focused ion beam (FIB). During the soft-lithography molding process, anti-adhesion layers were needed between the Silicon mold and H-PDMS samples to prevent the de-molding failure caused by the adhesion issues between the interfaces. This study adopts three methods to deposit anti-adhesion layers, such as liquid immersion, vapor deposition, and fluorine-doped diamond-like carbon (F-DLC) film. Perfluorooctyl-trichlorosilane (PFOTCS) was used as a mold-releasing agent for the liquid immersion and vapor deposition methods. The contact angles between each film were measured to determine the effect of anti-adhesion on the molding process. In addition, atomic force microscopy (AFM) was used to measure the adhesion force between the H-PDMS and anti-adhesion layers. The results show that the coatings of anti-adhesion layers are an effective approach to improve the formability of molding.

Synthesis of Ag3PO4 immobilized with sepiolite and its photocatalytic performance for 2,4-dichlorophenol degradation under visible light irradiation

A novel Ag3PO4-sepiolite composite photocatalyst was first synthesized using the liquid deposition method. And its characteristics were measured by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) analysis, X-ray photoelectron spectrometry (XPS), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface, UV–vis diffuse spectra and photoluminescence (PL). Moreover, the photocatalytic performance of Ag3PO4-sepiolite was tested for 2,4-DCP degradation under visible light irradiation, and enhanced photocatalytic activity and stability were achieved. Besides, the response surface methodology based on Box–Behnken design (BBD) was employed to investigate the effects of different reaction conditions on the removal of 2,4-DCP. The optimum conditions for 2,4-DCP degradation were as follows: solution pH value of 4.01, H2O2 concentration of 35.24 mM and catalyst dosage of 0.36 g L−1. Under these conditions, the experimental values for 2,4-DCP and TOC removal efficiencies were of 84.50% and 64.39%, which consisted with the predicted values of 84.65% and 64.48%, respectively. Furthermore, the free radical capture experiments indicated that reactive species of OH, O2·− and h+ were the main participants for oxidizing 2,4-DCP. The reaction intermediates were also identified by high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometer (GC-MS) technique.

Solid-state encapsulation of Ag and sulfadiazine on zeolite Y carrier

HypothesisA new simplified procedure for encapsulation of antibacterial silver nanoparticles by Solid-state Ion Exchange (SSIE) procedure over zeolite Y, followed by deposition of sulfadiazine (SD) by dry mixing was examined for the preparation of topical antibacterial formulations. The ion-exchange and adsorptive properties of the zeolite matrix were utilized for the bactericidal Ag deposition and loading of antibiotic sulfadiazine. ExperimentsAssessment of the encapsulation efficiency of both active components loaded by solid and liquid deposition methods was made by X-ray diffraction, TEM, FT-IR spectroscopy and thermogravimetric analysis (TGA). SD release kinetics was also determined. FindingsSustained delivery of sulfadiazine has been observed from the Ag-modified zeolites compared to the parent HY material. It was found that if SD was loaded in solution, part of the zeolite silver ions was released and interacted with SD, forming AgSD. By solid-state SD deposition, the reaction between the drug and the silver was restricted within the limits of inter-atomic interaction, and total but prolonged drug release occurred.

A joint experimental and theoretical study on ZnO nanocomposites synthesised by a liquid deposition method

ZnO was grown on mordenite zeolite, activated carbon and alumina substrates by a liquid deposition method. The photocatalytic activity of the synthesised samples was elucidated using the photodegradation of Acid Blue 92 (AB92) dyes as a test pollutant under UV light irradiation. Supports play a key role in AB92 photodegradation and significantly improve the photocatalytic activity of ZnO. Different supports form additional transport channels and provide an effective pathway for the charge carriers. The supports effectively construct porous structures with more active sites. Hence, the higher photocatalytic activity of supported catalysts is attributed to the large surface area and charge carrier separation. Bader's AIM theory showed that the strength and nature of intermolecular interactions between ZnO and the various supports is different. All geometry structures were optimised with B3LYP/6-31g (d) level theory. The performed local reactivity descriptors determined the reactive sites in molecules, demonstrating the mechanism for the enhanced photocatalytic activity of the composites. Both experimental and theoretical results confirm that the insertion of ZnO nanoparticles on the supports enhances electron transfer between ZnO and the catalyst surface, thus inhibiting charge recombination. The highest photocatalytic activity was observed for ZnO/MOR nanocomposite due to its high surface area, unique structure of MOR and photonic efficiency.

Enhanced electrochemical performance of Li4Ti5O12 as anode material for lithium-ion batteries with different carbons as support

Nano-Li4Ti5O12/carbon composites with various structures are designed using tetrabutyl titanate as a precursor via a facile in situ liquid deposition method in the presence of three different carbons (multiwalled carbon nanotubes, spherical conductive carbon black super-P and ordered macroporous carbon). The nano-Li4Ti5O12/carbon composites with various morphologies are formed depending on the carbon matrixes used. The Li4Ti5O12 particles obtained are approximately 100 nm in size and homogeneously dispersed in different carbon matrixes. It is found that the structures of the carbon matrixes have a close relation to the discharge capacities of the composites. At the discharge current density of 875 mA g−1, the discharge capacities of nano-Li4Ti5O12/carbon composites with 10 wt% carbon are 138.6, 120.8 and 120.9 mAh g−1 for carbon nanotubes, super-P and porous carbon as the carbon supports, respectively. The nano-Li4Ti5O12/carbon using carbon nanotubes as support exhibits superior performance with large reversible capacity, excellent cycle stability and good rate capability. Capacity retention of 99% can be maintained after 100 cycles, suggesting its promising potential as anode materials.

Study on the preparation and photocatalytic oxidation properties of TiO2/nano-Fe0 photocatalysts

TiO2/nano-Fe0 composite photocatalysts were prepared via a liquid phase reduction deposition method using anatase nano-TiO2 as a deposition substrate.

Effect of surface modification on the stability and thermal conductivity of water-based SiO2-coated graphene nanofluid

SiO2-coated graphene was prepared by chemical liquid deposition method by using tetraethyl orthosilicate (TEOS), and then SiO2 particles were successfully coated on the graphene surface. A new kind of stable water-based graphene nanofluid was further prepared using the functionalized nanomaterial (graphene/SiO2). The effect of SiO2-coated modification on the stability and thermal conductivity of water-based graphene nanofluid was examined. The results showed that SiO2-coated modification significantly improved the hydrophilicity of graphene, as well as the stability and thermal conductivity of water-based graphene nanofluid. SiO2-coating can improve thermal conductivity better than surfactants for preparing water-based graphene nanofluid.

Quantitative detection of trace explosive vapors by programmed temperature desorption gas chromatography-electron capture detector.

The direct liquid deposition of solution standards onto sorbent-filled thermal desorption tubes is used for the quantitative analysis of trace explosive vapor samples. The direct liquid deposition method yields a higher fidelity between the analysis of vapor samples and the analysis of solution standards than using separate injection methods for vapors and solutions, i.e., samples collected on vapor collection tubes and standards prepared in solution vials. Additionally, the method can account for instrumentation losses, which makes it ideal for minimizing variability and quantitative trace chemical detection. Gas chromatography with an electron capture detector is an instrumentation configuration sensitive to nitro-energetics, such as TNT and RDX, due to their relatively high electron affinity. However, vapor quantitation of these compounds is difficult without viable vapor standards. Thus, we eliminate the requirement for vapor standards by combining the sensitivity of the instrumentation with a direct liquid deposition protocol to analyze trace explosive vapor samples.

Preparation, photocatalytic properties and mechanism of Fe or N-doped Ag/ZnO nanocomposites

Fe or N-doped Ag/ZnO nanocomposites were synthesized by the dual-step liquid deposition method and one-step liquid deposition combined with plasma nitriding. The as-synthesized nanocomposites were characterized by transmission electron microcopy, high-resolution transmission electron microcopy, X-ray diffraction and X-ray photoelectron spectroscopy. In addition, the photocatalytic properties of Fe or N-doped Ag/ZnO nanocomposites were evaluated by the degradation of methyl orange (MO) under ultraviolet light irradiation using our self-made photocatalytic apparatus. Results showed that Fe or N-doped Ag/ZnO nanocomposites exhibited superior photocatalytic properties compared to the undoped Ag/ZnO nanocomposites. The concentration of ferric sulfate solution and doping ratio of n(Fe): n(ZnO) played an important role in improving photocatalytic properties of Fe-doped Ag/ZnO nanocomposites and the optimized concentration and doping ratio were determined to be 0.134M and 5%, respectively. Moreover, the plasma nitriding time also played an important role and the optimal plasma nitriding time was 30min. The enhanced photoactivity mechanism for Fe or N-doped Ag/ZnO nanocomposites was adequately discussed.

Porosity modulation of activated ZIF-templated carbons via compaction for hydrogen and CO2 storage applications

The mechanical stability of activated ZIF-templated carbon materials, prepared via liquid impregnation and chemical vapour deposition (CVD) methods, was investigated by compaction at various pressures (compaction loads of 5 and 10 tonnes equivalent to 370 and 740 MPa, respectively). Compaction at 5 tonnes (370 MPa) was, unusually, found to increase the textural properties (surface area and pore volume) and gas (hydrogen and CO2) uptake capacity. In particular, compaction at 5 tonnes resulted in higher micropore surface area and pore volume, and an overall rise in the total surface area and pore volume. Compaction resulted in an improved gas uptake capacity of 6.5 wt% hydrogen (at −196 °C and 20 bar) and 2.4 mmol g−1 of CO2 (at 25 °C and 1 bar) for an activated ZIF-templated carbon compacted at 5 tonnes following preparation via liquid impregnation and carbonisation at 900 °C. When the carbon was compacted at 10 tonnes (740 MPa), the hydrogen and CO2 uptake was marginally lower at 5.7 wt% and 2.2 mmol g−1, respectively, compared to the uptake of 6.2 wt% hydrogen and 2.0 mmol g−1 CO2 for the equivalent non-compacted sample. More importantly, increase in packing density after compaction resulted in up to 70% improvement in volumetric hydrogen uptake, which reached 42.3 g l−1 at −196 °C and 20 bar, much higher than that for conventional activated carbons, and one of the highest values ever reported under these conditions. The genesis of the increase in textural properties after compaction appears to be linked to the pore size distribution and mechanical stability of the activated ZIF-templated carbons and their structural rearrangement under compaction, especially at a load of 5 tonnes that results in an increase in the proportion of microporosity.

Enhanced high rate and low-temperature performances of mesoporous LiFePO4/Ketjen Black nanocomposite cathode material

The well-crystallized LiFePO4 cathode material was synthesized by liquid deposition method using mesoporous Ketjen Black (KB) as template. The LiFePO4/KB nanocomposite was characterized by X-ray diffraction (XRD), TG, SEM, HR-TEM, nitrogen sorption, galvanostatic charge/discharge test and EIS. The results indicate that the LiFePO4 particles about 10nm were embedded in the mesoporous of Ketjen Black. The composite has an uniform particle size and 3D network structure, which delivers a discharge capacity of 120.2mAh/g, 100.1mAh/g, 85.5mAh/g and 64.5mAh/g at 1C, 5C, 10C and 20C under −20°C respectively. Moreover, the composite also exhibit relatively high cycling performance and the capacity maintains 93.6% at 5C and 91.2% at 10C under −20°C after 200 cycles. The stable high rate performance possibly fulfills the requirements of rechargeable lithium batteries for high power applications especially at low temperature.