Chemical Liquid Deposition Method Research Articles

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...

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.

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.

Preparation and photo-catalytic activity of TiO2-coated medical stone-based porous ceramics

Medical stone-based porous ceramics as a carrier were prepared by ultra-fine grinding and low-temperature sintering method. Nano-TiO2 thin films were loaded on the carrier by chemical liquid deposition method using titanium tetrachloride as a precursor. The micro-morphology and microstructure of the synthesized samples were characterized using X-ray diffraction, scanning electron microscopy with energy dispersive spectrometry, and mercury injection method. The photo-catalytic activity of the TiO2 thin films was investigated by degrading formaldehyde. The main crystalline phase in the TiO2 thin films calcined at 550°C is anatase with the average particle size about 10 nm. The specific surface area of the carrier-coated nano-TiO2 increases from 3.68 to 5.32 m2/g. The formaldehyde removal rate of the TiO2/medical stone-based porous ceramics irradiated under an ultraviolet lamp for 120 min reaches 85.6%.

Synthesis of Al/Fe3Al core–shell intermetallic nanoparticles by chemical liquid deposition method

In this work, an Al/Fe3Al core–shell nanoparticle was obtained by heat treatment of a precursor in high purity of argon. The precursor, with Fe(CO)5 and nano Al as raw materials, was synthesized simply by a chemical liquid deposition method. The evolution of the phase and morphology during the heat-treatment has been carefully studied by XRD and TEM. The results indicate that the precursor transformed to core–shell structure of Fe3Al intermetallic nanoparticle. The formation of the Fe3Al intermetallic nanoparticle was explored by DSC test, which reveals that the formation temperature of the nanoparticle is around 587°C. Moreover, the TG–DSC measurements from 50°C to 1000°C in compressed air (20% O2 and 80% N2) reveal that the heat-treated powder of the precursor remains thermal stability in relatively low temperature but becomes concentrated combustion in elevated temperature.

Designed constitution of NiO/Ni nanostructured electrode for high performance lithium ion battery

Porous NiO/Ni foam electrode is fabricated by a simple two-step method. Firstly, nickel hydroxide hydrate nanoflakes are deposited on Ni foam via a chemical liquid deposition (CLD) method. Then NiO/Ni architecture is obtained by subsequent graft growth in air atmosphere at 350°C. Galvanostatic battery testing shows that NiO electrode exhibits fine capacity retention and good rate performance. It exhibits high initial discharge and charge capacity of 1.94 and 1.36mAhcm−2, maintaining of 1.41 and 1.38mAhcm−2 after 140 cycles under a discharge/charge rate of 0.4C. It delivers high discharge capacity retention of 70% (comparing with that of 0.2C) even at a high rate of 2.5C. After that, the discharge capacity can gradually resume along with the decrease of discharge/charge rate, showing capacity retention of 105% when lowering the discharge/charge rate to 0.2C. The fine electrochemical performance of NiO/Ni is due to the maintenance of porous architecture and the prevention of active nano-sized NiO from aggregation in cycling, which is relevant to both the interweaved structure of NiO nanoflakes and the graft growth between NiO and Ni.

Evolution of binary Fe2O3/SiO2 coating layers on the surfaces of aluminum flakes and the pigmentary performances

Binary Fe2O3/SiO2-coated aluminum pigments were prepared by chemical liquid deposition method using tetraethyl silicate (TEOS) and FeCl3 as the precursors of SiO2 and Fe2O3, respectively. The chemical structure and the evolution mechanism of the binary Fe2O3/SiO2 coating layers were investigated by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, powder X-ray diffraction, and scanning electron microscopy techniques. The binary Fe2O3/SiO2 coating layers were anchored at aluminum flake surfaces via SiOAl and FeOSi bonds. The anticorrosive performance of the SiO2-coated aluminum flakes was significantly improved as compared with the naked aluminum flakes, indicating that SiO2 coating layers were densely and tightly formed on the surfaces of aluminum flakes. The pigmentary performances of the binary Fe2O3/SiO2-coated aluminum samples were analyzed by CIE, showing that yellow and red colored aluminum-based pigments were achieved by varying the Fe2O3 loading on SiO2-coated aluminum flake substrates.

Photocatalytic activity of bauxite-tailings supported nano-TiO2

TiO2/bauxite-tailings (TiO2/BTs) composites were prepared via a chemical liquid deposition method and characterized by X-ray diffractometry (XRD), scanning electronic microscopy (SEM) and N2 adsorption analysis. The photocatalytic performance of TiO2/BTs composites was evaluated with UV-Vis spectrophotometer following the changes of phenol concentration under different illumination time. Effects of the calcination temperature, the pH and the cycles on the photocatalytic activity of TiO2/BTs composites were investigated. The composites calcined at 500 and 600 °C exhibit the best photocatalytic performance, and the phenol degradation ratios reacting for 40 and 160 min reach 35% and 78% respectively under the same conditions, higher than those of 29% and 76% of the Degussa P25(TiO2). The ability of TiO2/BTs500 (BTs500 represents bauxite-tailings calcined at 500 °C) composites to degrade phenol increases with decreasing pH.

Evolution of zirconia coating layer on rutile TiO 2 surface and the pigmentary property

Zirconia-coated rutile TiO 2 composites were prepared by the chemical liquid deposition method starting from rutile TiO 2 and ZrOCl 2. The amorphous zirconia coating layers were anchored at the TiO 2 surface via Zr–O–Ti bond. The formation of continuous and dense zirconia coating layers was dependent on the pH value of the reaction solution and the mole ratio of ZrOCl 2 to TiO 2. As compared to the naked rutile TiO 2, the water dispersibility, whiteness, brightness, and relative light scattering index of the zirconia-coated rutile TiO 2 composites were increased.

Microstructure and properties of SiC gradiently coated C f/C composites prepared by a RCLD method

The SiC gradiently coated carbon fiber/carbon (C f/C) composites were prepared by a two-step rapid chemical liquid deposition (RCLD) method. The microstructure and properties of the composites were investigated using X-ray diffraction, scanning electron microscopy together with energy dispersive X-ray analysis, bending tests, and oxidation tests. The experimental results show that the surface layer of the composites is composed of SiC, pyrocarbon, and carbon fibers. Their inner area consists of pyrocarbon and carbon fibers. The SiC content gradiently decreases with increasing distance from the outer surface to the center of the composites. Furthermore, the thickness of the SiC layer increases with increasing tetraethylorthosilicate content and deposition time. SiC coatings have no significant influence on the bending strength of the composites. However, the oxidation resistance of the composites increases with increasing thickness of the SiC layer.

Evolution mechanism of alumina coating layer on rutile TiO 2 powders and the pigmentary properties

The evolution of alumina coating layers on rutile TiO 2 particle surfaces was investigated starting from aluminum sulfate by a chemical liquid deposition method. The morphology of the alumina coating layers was determined by transmission electron microscopy. The chemical structure and the evolution mechanism of the alumina coating layers on TiO 2 surfaces were investigated by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and powder X-ray diffraction techniques. The dispersibility of the alumina-coated TiO 2 powders was determined by dynamic laser scattering (DLS) mode. The alumina coating layers existed in boehmite phase, AlOOH, and anchored at the surfaces of TiO 2 via Ti–O–Al bond. The formation of alumina coating layers on TiO 2 surfaces depended on the pH value of the deposition solution and the alumina loading. After coated by alumina layer, the dispersibility, whiteness, brightness, and light scattering index of the resultant samples were promoted.

Ultrathin gold film deposited on human hair: Derivation from nanoparticles and applications as microsensors

An ultrathin film of gold was grafted on human hair by a chemical liquid deposition method under ambient conditions. The method consisted of the assembling of gold nanoparticles (GNPs) on the adsorptive sites of human hair as seeds and the growth of isolated GNP seeds into a continuous gold layer. The resulting gold film coated hair possessed good conductivity and flexibility, and can be used as a novel gold hair microelectrode (GHME). This electrode inherited some merits of both hair and gold nanoparticles, for instance, good mechanical property, excellent biocompatibility and high surface area. GHME was also proven to exhibit sensitive electrochemical responses toward dopamine and nitric oxide, foreseeing its promising applications in the fields of biomedical analysis.

Evolution mechanism of alumina nanofilms on rutile TiO 2 starting from sodium metaaluminate and the pigmentary properties

Alumina-coated rutile TiO 2 samples were prepared starting from NaAlO 2 by the chemical liquid deposition method. The alumina nanofilms existed in amorphous hydrated alumina phase and anchored at the surfaces of TiO 2 particles via Ti–O–Al bonding. The formation of continuous and dense alumina nanofilms on the TiO 2 surface depended on the pH value of the reaction solution and the alumina loading. After coated by alumina nanofilms, the whiteness and brightness of the alumina-coated TiO 2 samples increased with the increase of the alumina loading while the relative light scattering index was found to depend upon the alumina loading.

Synthesis and aggregation study of tin nanoparticles and colloids obtained by chemical liquid deposition

Tin colloids (Sn-Colls) and nanoparticles were synthesized by a chemical liquid deposition method (CLD). Sn0 was evaporated and codeposited with acetone, 2-propanol, and tetrahydrofurane vapors at 77 K to obtain colloidal dispersions. Sn-Coll were characterized by UV spectroscopy, transmission electron microscopy (TEM), high resolution transmission electron microscopy, selected area electron diffraction, thermal analysis, infrared spectroscopy [Fourier transform infrared (FTIR)], and light scattering. TEM micrographs of tin nanoparticles (Sn-Nps) revealed a particle size distribution between 2 and 4 nm for the three solvents used in the synthesis. UV studies showed strong absorption bands in the UV region, suggesting that the Sn-Nps obtained by CLD exhibit quantum confinement and typical bands of plasmons corresponded to aggregated particles. Electrophoresis measurement indicated a significant tendency of particle aggregation along time, which was verified by light scattering studies. The diffraction patterns revealed phases corresponding to metallic tin and FTIR studies showed the interaction Sn-solvent in the metal surface by Sn-O bonds, indicating a solvatation of metallic clusters. Thermal analysis revealed a good thermal stability of Sn-Nps. The mechanism of tin nanoparticles formation was also examined.

Preparation and Characterization of Coated ZnO Nanoparticles

SiO2 coated and SiO2/Al2O3 coated nano-ZnO were synthesized by chemical liquid deposition method. The surface properties and dispersion stability of the coated and uncoated ZnO nanoparticles were characterized. The results showed that a SiO2 or SiO2/Al2O3 amorphous layer was coated on the ZnO nanoparticles. The adsorbed hydroxyl content of ZnO was found to increase accompanied by the decrease of UV-shielding ability by surface modification; moreover, the isoelectric point of ZnO slurry was changed, and the stability of nano-ZnO in water was also improved effectively.

Size evolution of palladium nanoparticles from low-temperature solvated atoms

Palladium nanoparticles were synthesized by the chemical liquid deposition method. In this method Pd atoms, produced by resistive heating, were co-deposited at 77 K with 2-propanol vapors to obtain a frozen metal-organic matrix, which is then melted to obtain a colloidal dispersion. In this work, we study the effect of the melting or warm-up rate of the frozen matrix on the characteristics of nanoparticles. The colloidal dispersions were characterized by FTIR, TEM and HRTEM techniques. The FTIR spectra reveal that the carbonaceous fragments are anchored on Pd particles. Studies in TEM and HRTEM micrographs reveal higher mean particle size (∼5 nm), broader size distributions and irregular shapes when the melting process is faster, whereas for a slower warm-up process, it was found smaller particle sizes (∼2 nm), narrower size distributions and regular particle shapes like cuboctahedron, tetrakaidecahedron and icosahedron.

Metal-organic chemical liquid deposited (1 1 0)-preferred LaNiO 3 buffer layer for Pb 0.97La 0.02(Zr 0.85Sn 0.13Ti 0.02)O 3 antiferroelectric films

Conductive perovskite lanthanum nickelate LaNiO 3 (LNO) thin films were fabricated on SiO 2/Si substrates through metal-organic chemical liquid deposition method. The effect of annealing temperature on the orientation and sheet resistance of the LNO films were investigated. XRD patterns showed that the LNO films deposited on SiO 2/Si substrates exhibited preferred-(1 1 0) orientation. The lowest sheet resistance of the LNO thin films, 250 Ω/□ was obtained after being annealed at 650 °C for 1 h. Subsequently, Pb 0.97La 0.02(Zr 0.85Sn 0.13Ti 0.02)O 3 (PLZST) antiferroelectric thin films were prepared on the LaNiO 3 buffered SiO 2/Si substrates via sol–gel process. And the crystallinity, microstructure and electric properties of the PLZST thin films were studied in details.

Synthesis and electrical property of antimony-doped tin oxide powders with barite matrix

Antimony-doped tin oxide (Sb-SnO2) nanoparticles were deposited on barite (BaSO4) to produce Sb-SnO2/barite (SSB) composite conductive powders via a chemical liquid deposition method. Effects of hydrolysis temperature, pH value, percentage of barite, doping concentration of antimony, calcination temperature and time on the resistivity of the SSB composite powder were primarily investigated. SSB powders with resistivity of less than 1.5×103Ωcm can be successfully obtained under the optimum experimental parameters. The samples were characterized by scanning electronic microscopy (SEM) and X-ray diffraction (XRD). The precursors of Sb-SnO2 powder were researched by means of thermogravimetric analysis (TG) and Fourier transform infrared (FTIR) spectroscopy in order to discuss the mechanism of hydrolysis reaction.