DanpingWang., et al, developed the poroustungsten oxide/copper tungstate (WO3/CuWO4) composite thin films via facile in situ conversionmethod, with a polymer templating strategy. Copper nitratesolution with the copolymer surfactant was added on to WO3 substratesby planned dip coating andfollowed by heat treatment in air at 5000C. The Cu2+ reacted with the WO3 substrate toproduce the CuWO4compound. The composite WO3/CuWO4 thin films represented wellimproved photoelectrochemicalresults over CuWO4 and WO3 single phase photoanodes. Thefactors of charge separation andlight absorption performance of the composite and 2 single phase films were checked to understandthe reasons for the Photoelectrochemical enhancement of WO3/CuWO4composite thin films. Thephotocurrent was generated from water splitting as proved by hydrogen and oxygen gasevolution, and Faradic efficiency was determined based on the amountof Hydrogen gas produced.
Thiswork provided a low-cost and controllable way to prepare WO3-metaltungstate composite thin films,and also made easy to deepen the know about the charge transfer inWO3/CuWO4heterojunction. (1)S. G.
Krishnan and C. Rejitha prepared Pure andcadmium-doped copper oxide NPs by a microwave assisted solvothermal way usingcopper acetate as the starting material. The particle sizes of these NPsproduced were 10-15nm for pure CuO and 43-90 nm for cadmium-doped CuO NPs. Theprepared both pure and cadmium doped copper oxide NPs have been evaluated byusing Scanning Electron Microscope, X-Ray Diffraction and UV–Visible analysis techniques.From the XRD study, it was clear that the synthesized samples are in themonoclinic system. Scanning Electron Microscopy (SEM) pattern shows the roundshaped morphology of the synthesized nanoparticles.
The presence of dopant inthe doped sample is known by using EDAX calculations. The optical property ofcadmium-doped copper oxide NPs are determined by UV-Visible spectroscopy. (2)XiangLiu., et al, electrodeposited the nanostructured copperoxide thin coatings from copper (II) complexes which can catalyze the oxygenevolution reactions. Cyclic voltammetry and bulk electrolysis using copperoxide thin film electrode in basic aqueous solutions represented thesignificant catalytic currents. The catalyst film was analyzed by X-raydiffraction, scanning electron microscopy, energy-dispersive X-ray analysis andX-ray photoelectron spectroscopy. The results show that nanostructured copperoxide is very active electrocatalyst for water oxidation.
(3)SulekhChandra., et al, prepared Cu NPs by solution reduction process successfully.The effect of parameters on the size of Cu NPs was investigated and the referentialprocess factors were gathered. The morphology and structure of the prepared Cunanoparticles were analyzed by powder X-ray diffraction (XRD), transmissionelectron microscopy (TEM), QELS data, solid state UV and infrared spectroscopy(IR). The mean size of nanoparticles was obtained between 14 ± 2 nm.
(4)RosaE., et al, deposited Silver nanoparticles on titanium oxide thin filmsfabricated on FTO (fluorine-doped tin oxide) glass with the help of a doublepulse electrochemical deposition procedure. A systematic study of growth andparticle nucleation was shown as a function of time and applied potential.Samples were characterized by grazing-angle X-ray diffraction (GIXRD) techniqueand morphology was observed using SEM and Energy Dispersive Spectroscopy device(EDS).
Results proved the possibility ofcontrolled electrochemical homogeneous fabrication of metallic silver particlesover TiO2 surface, which show a potential application in catalyticprocess. (5)Yong-JaeChoi and Tzy-Jiun M. Luo synthesized the silver nanoparticles withinaminosilica film from spontaneous reduction reaction and investigated the electrochemicalproperties of silver nanoparticle (d ? 5 nm) using cyclic voltammetry.Results depicted that the nanocomposite film shows similar redox property assolution-synthesized silver NPs when calculating in phosphate buffer solutionand its redox potentials were obtained to be sensitive to the presence ofchloride ion. It also depicted that hydrolyzed aminosilica and silvernanoparticles increase the electron diffusivity of the aminosilica film.
Bothresults prove that an accurate reference electrode suitable for microfluidicdevices can be prepared simply by treating an aminosilica-coated electrode witha silver nitrate solution. And also, a humidity sensor consisted on silver-silicananocomposite film has been demonstrated. (6)NataliaL., et al, revised some of the most relevant and mostly used synthetic methodspresent for the synthesis of metallic silver nanoparticles. Special emphasishas been focused in the rationale included in the formation of thenanostructures, from the early metallic silver atoms preparation, passing byatoms nucleation and ultimately ends in the growth of silver nanostructures. (7)JavedIjaz Hussain., et al, reported the effect of aniline amount on the growth andsize of silver nanocrystal using aniline and silver nitrate used as a reductantand oxidant. Transmission electron microscopy (TEM), UV-Vis spectroscopy, andselected areas electron diffraction (SAED) have been used to analyze silvernanoparticles.
The TEM depicts that silver nanocrystals are roughly round andof evenly distributed particle size, and the average particle size is ca. 26 nm. A broad surface plasmonresonance band was shown at 400 nm. The rings patterns are in fine agreementwith the standard values of the facecentered-cubic shape of silver nanocrystals.
This is connected to the adsorption of aniline and interparticle interactiononto the surface of Ag-nanocrystals through electrostatic interactions betweenthe lone-pairs electrons of –NH2 and positive surface of Ag-nanoparticles. (8)R.Solarskaa., et al, deposited Silver NPs on FTO conductive glass substrate andwithin n-type WO3 films synthesized by a sol-gel method.
A largeimprovement in water splitting photocurrents under AM1.5 visible lightirradiation for the WO3 photoanode with Ag nanoparticles wasdemonstrated. Ag NPs arrangement on FTO to generated localizedsurface plasmon under the visible wavelengths with the WO3 over-layer wasconfirmed by scanning near-field optical microscopy (SNOM) investigations. (9)MajidAhmadi, Reza Younesi and Maxime J-F Guinel synthesized tungstite (WO3.H2O)NPs by using a simple and cheap low temperature and low pressure hydrothermalprocedure in addition of HCl to diluted sodium tungstate solutions (Na2WO4.2H2O)at temperatures below 4oC. A heat treatment at temperatures at orabove 300oC resulted in a phase transformation to monoclinic WO3,while preserving the NPs morphology. The products were investigated by usingpowder x-ray diffraction, transmission electron microscopy and x-rayphotoelectron spectroscopy.