Electrochromic (EC) performances of Ni3+ containing NiO thin films, called modified NiO thin films, prepared either by pulsed laser deposition or by chemical route are reported. When cycled in lithium based electrolyte, the comparison of the EC behavior of nonstoichiometric NiO thin films points out a larger optical contrast for the films synthesized by chemical route with the absence of an activation period on early electrochemical cycling due in particular to a larger porosity. Herein we demonstrate faster kinetics for modified NiO thin films cycled in lithium ion free electrolyte. Finally, X-ray absorption spectroscopy is used for a preliminary understanding of the mechanism involved in this original EC behavior linked to the film characteristics including their disorder character, the presence of Ni3+ and their porous morphology.

Novel nickel oxide coatings (100-600 nm in thickness) with low surface roughness ( < 20 nm) and haze levels down to 6% were deposited at a temperature not higher than 150 degrees C on FTO glass and conducting plastic films. The coatings were deposited on the substrates from water dispersions made of Ni1-xO pigment synthesized via the peroxo route by reaction of a H2O2/urea mixture with Ni-acetate precursor. The bunsenite Ni1-xO pigment was obtained after thermal treatment of xerogels at 400 degrees C for 24 h. Processing common for paint manufacturing was applied for the preparation of water dispersions of the Ni1-xO pigment, i.e., intensive milling of the pigment with dispersant. Dispersant (NiOxHy) was prepared by colloidal precipitation technique from Ni-sulfate precipitated with sodium hypochlorite.The materials (Ni1-xO pigment, NiOxHy precipitate, coatings) were investigated using various analytical techniques (TG, DSC, SEM, TEM. IR and optical spectroscopy), while the electrochromic properties were determined by means of in situ spectroelectrochemical measurements, applying standard electrochemical techniques (cyclic voltammetry, chronocoulometry). The results revealed a convenient, simple, and robust technique for making "electrochromic paint" coatings from pre-prepared Ni1-xO pigment. They demonstrate the potential of the described electrochromic coatings for manufacturing plastic film based electrochromic devices providing transmissive light modulation. (C) 2012 Elsevier B.V. All rights reserved.

The influence of the addition of a mixture of PUSS compounds substituted equally by 3-aminopropyl and isobutyl groups (AP(4)IB(4) POSS) on sol-gel coatings prepared from (3-glycidoxypropyl)trimethoxysilane (GPTMS) was evaluated from the point of view of their anticorrosion properties. AP(4)IB(4) PUSS belong to a group of polyhedral oligomeric silsesquioxanes and their functionalisation with amino groups enables cross-linking with the epoxy groups of GPTMS. Additionally, GPTMS molecules react among themselves through hydrolysis and condensation processes of trimethoxysilane groups when catalysed by 0.1 M KF. The results of the Raman and IR measurements revealed that a molar ratio of GPTMS:H(2)O = 1:3 is more beneficial than a molar ratio of 1:1.5 for the preparation of sol-gel coatings. The anticorrosion properties of the mixed GPTMS/POSS coatings deposited on AA 2024 aluminium alloy were tested using potentiodynamic electrochemical measurements and a salt-spray chamber test. It was found that the mixed GPTMS/POSS coatings showed improved corrosion protective properties vs. either pure GPTMS or PUSS coatings. (C) 2011 Elsevier B.V. All rights reserved.

Papermill sludge (PMS) is generated during the wastewater treatment process of paper production. Its handling and disposal techniques are of great concern for the environment. It can be landfilled as a waste, or it can be recycled and converted into useful products of high value. It has a very promising application as an absorbing agent for the cleaning of water surfaces polluted with hydrophobic substances (vegetable, synthetic and mineral oils, animal fats, fuels, organic chemicals and even coal dust). Here, we present the pretreatment procedure (hydrophobation, mechanical and thermal treatments) of PMS that produces a lightweight absorbent material (HAWSC – high efficiency absorbent for water surface cleaning), which floats on the water surface and binds hydrophobic pollutants with considerably higher efficiency than commercially available mineral and synthetic absorbents. After its application, it can be incinerated, due to its high caloric value, to produce energy. The incineration residues can then be formed into granules that can be used as an efficient absorbent for fluids spilled onto solid surfaces.

A series of plastic devices composed of an inorganic oxide as ion storage layer, PEDOT as electrochromic layer and a mixture of ionic liquid and polymer based on the same ionic liquid have been assembled. It is known that inorganic oxides used in electrochromism required the presence of Li + from the electrolyte in order to perform the corresponding redox reaction. However, in the present research we were able to use a Li + free electrolyte by using a lithiated counter electrode. In addition, the counter electrodes were prepared at low temperatures appropriate for the deposition of thin films on plastic ITO substrates. Several strategies have been followed in order to prepare lithiated counterelectrodes. For instance in the case of vanadium oxide prepared at 150 °C, the starting V 2O5 1 material was reduced at -0.2 V (vs. Ag/AgCl) for several minutes leading to Li xV2O5 which was used as counter electrode. The electrochromic material used in these devices was PEDOT (poly(3,4ethylenedioxithiophene)) which was synthesised following a chemical oxidative route. 2 The electrolyte used in this system is a mixture of ionic liquid 1-ethyl-3-butyl imidazolium PF 6 and a polymer based on such ionic liquid. Following such strategy, an electrochromic device with colour change between light yellow and bluish grey has been assembled, showing a cyclability up to 2000 cycles. Other inorganic counter electrodes such as Li xFe-oxide has also been studied using a similar strategy. This research has been funded from the European Community’s Seventh Framework

A method based on FT-IR near-grazing-incidence-angle reflection–absorption spectroscopy and the phenomenon of the Berreman effect was developed for the estimation of the compactness or density of thin films. The testing of the method was performed on amorphous and nanocrystaline Cu-oxide thin films, which were prepared on Au covered glass and Si wafer substrates by wet chemistry route using dip-coating technique. The density of the film was used as a parameter, which was adjusted in the simulation calculation until the sufficient agreement between calculated and experimental near-grazing angle reflection spectra was achieved. The results showed the increase in density of Cu-oxide films with repeated dip-coating cycles. This was in agreement with the observation of the microstructure with TEM and SEM.

Spinel Co3O4 and Li-doped Co3O4 thin film electrocatalysts deposited on Pt and ITO/glass substrates were prepared by the sol–gel route from Co(II) sulfate precursor using dip-coating technique. Stoichiometry of undoped and Li+ doped films (up to 10 mol% of Li+) prepared at 300 and 500°C, respectively, showed deficiency with Co(III) ions in the film structure. All films exhibited substantial electrical conductivity (σ) which was slightly dependent on the type of the substrate. The roughness factor, RF, of electrodes was determined by cyclic voltammetry. Spinel oxide films prepared at lower temperatures (300°C) showed high surface area (RF∼700). The electrocatalytic properties were studied by different electrochemical methods in alkaline solutions. The results of electrochemical measurements in KOH indicated the formation of surface quasi-reversible redox couple, Co(IV)/Co(III), which is limited by a diffusion-controlled process. The oxygen evolution potentials pointed out remarkable performance of Co3−xO4 (300°C) and Li+ doped Co3−xO4 (500°C) films. The reaction order with respect to [OH−] was found to be nearly 1.2. Durability testing of films in 5 M KOH at 70°C showed high long-term performance and structure stability of Li+ doped Co3−xO4 (500°C) films.

Layered LixCoO2 and LixNiO2 thin films (x∼1) were prepared by a peroxo wet chemistry route from Li(I), Co(II) and Ni(II) acetate precursors and the addition of H2O2. Structural changes during the processing of xerogel to final oxide were followed by X-ray diffraction and infrared spectroscopy. Electrochromic properties were determined with in-situ potentiodynamic, potentiostatic and galvanostatic spectroelectrochemical measurements. Single dipped films with composition Li0.99Co1.01O2 or Li0.94Ni1.06O2 exhibited stable voltammetric response in 1 M LiClO4/propylene carbonate electrolyte after about 60 cycles. The total charge exchanged in a reversible charging/discharging cycle was about ±30 mC cm−2 for Li0.99Co1.01O2 and ±20 mC cm−2 for Li0.94Ni1.06O2 oxide films. Galvanostatic measurements showed that about 1/2 (x∼0.5) and 2/3 (x∼0.3) of Li+ ions could be reversibly removed from the structure of Li0.99Co1.01O2 and Li0.94Ni1.06O2 films, respectively. Practical applicability of Li0.99Co1.01O2 and Li0.94Ni1.06O2 oxide films was studied in electrochromic devices with WO3‖(H+)Li+ormolyte‖Li0.99Co1.01O2 and WO3‖(H+)Li+ormolyte‖Li0.94Ni1.06O2 configuration. The monochromatic transmittance Ts (λ=633 nm) of dark blue coloured devices was extremely low (Ts∼3%), whereas in bleached state the value reached around Ts∼70%.

Layered lithiated Co- and Ni-oxide powders and thin films with rhombohedral (R 3̅ m) structure were prepared by a peroxo wet chemistry route from Li(I), Co(II) and Ni(II) acetate precursors and the addition of H2O2. XRD analysis revealed that xerogel films and powders possessed a typical layered structure. Layered (R 3̅ m) Li 0.99 Co 1.01 O 2 powder and Li 0.97 Co 1.03 O 2 films were formed around 500°C, while Li 0.93 Ni 1.07 O 2 powder and Li 0.94 Ni 1.06 O 2 oxide films were prepared around 550°C. The stoichiometry of the oxide films and powders was dependent on the heat-treatment temperature. The structure of sols, gels, xerogels and thin films was established from XRD spectra and from the FT-IR spectra, confirming their layered structure.

Laminated electrochromic (EC) devices are becoming increasingly important for making “smart” windows and switchable displays. Mostly, polymeric Li+ ionic conductors in combination with vacuum deposited active electrochromic and counter-electrode films are used. In this paper we report on the development of all sol–gel EC devices, that is, those where all three internal layers are prepared via the sol–gel route, including the ionically conductive inorganic–organic hybrid (ormolyte). The electrochemical and optical properties of EC devices are presented and the cycling stability and reversibility of their optical modulation assessed. The results show that WO3/ormolyte/SnO2:Mo, WO3/ormolyte/SnO2:Sb, WO3/ormolyte/SnO2:Sb:Mo, Nb2O5/ormolyte/SnO2:Sb:Mo and WO3/ormolyte/LiCo-oxide exhibit a transmission modulation dependent on the thickness of the active electrochromic and counter-electrode films and the thickness of the ormolyte layer. Electrochemical and optical properties of individual films are described and correlated with the stability of the all sol–gel EC devices.

Tungsten oxide doped by a complex of platinum exhibits a gasochromic effect. A reversible coloration is observed on successive exposure to hydrogen and air. The films were prepared by the sol-gel method at room temperature. They showed strong darkening (blue color) on exposure to hydrogen and were bleached completely when exposed to air. The proccess has been reproduced completely hundreds of times without any losses. The cycling of the coloration was obtained from UV-Vis spectra and the mechanism deduced from both visible and Fourier transform infrared (FTIR) spectra. Colorimetric properties of the gasochromic films were expressed in color space chromaticity diagram.

The sol-gel dip-coating technique was used for depositing cubic spinel Co 3 O 4 and amorphous Co/Al/Si-oxide thin films. Both types of films exhibit similar electrochrochemical properties which are accompanied by the hydration of the structure. The electrochromic properties of Co/Al/Si-oxide surpass those already known for Co-oxide based electrochromic materials. The change in transmittance for spinel Co 3 O 4 is 25%, while for Co/Al/Si-oxide films exceeds 50%. The electrochromic efficiency (η) for Co 3 O 4 and Co/Al/Si-oxide films was 22 cm 2 C -1 , which is comparable to other electrochromic oxides. Good electrochromic properties of the Co/Al/Si-oxide films make them promising materials for active counter electrode in electrochromic devices.

Thin films of the cubic spinel Co3O4 were prepared by the sol-gel route from a Co(II) sulfate precursor using a dip-coating technique. The films (50 to 60 nm thick) were deposited on indium-tin oxide glass substrates with a single dipping. The electrochromic properties of the films mere studied in an aqueous alkaline electrolyte (0.1 M LiOH) using cyclic voltammetry (CV) and in situ UV-vis spectroelectrochemistry. The intermediate oxide products that appeared during cycling at current peak potentials were analyzed by x-ray diffraction (XRD) and ea: situ Fourier transform infrared (FTIR) reflection-absorption spectroscopy performed at near-grazing incidence angle conditions (NGIA), High hydration of the spinel structure enables complex redox processes to take place inside the structure or on the surface of the film when potential cycling is performed. Vibrational bands characteristic of the formation of CoO, Co(OH)(2), and hydrated Co3O4 phases have been assigned and discussed according to the results obtained from ex situ NGIA FTIR, CV, and XRD studies. The change in transmittance (lambda = 634 ma) between bleached and colored states for single-dipped films was 25%, and for electrochromic efficiency (eta) Was approximately 25 cm(2) C-1.

New electrochromic spinel-type Co(Al)-oxide and Co(Al,Si)-oxide films exhibiting coloring/bleaching changes ΔT= Tcolored−T bleached = 75% − 25% = 50% (where T is transmittance) with a coloring efficiency of 22cm2 C−1 were deposited by a dip-coating method from aqueous colloidal solutions made by thermal hydrolysis of Co(II)-acetate, Al(III)-sulphate, citric acid and 3-aminopropyltriethoxysilane precursors. The nanocomposite spinel structure of the films and powders was determined using X-ray diffraction, thermogravimetry, visible and infrared transmission and reflection-absorption spectroscopy performed at near-grazing incidence angle conditions (80°) using p-polarized light. The existence of spinel lattice modes in the IR spectra of cycled films proved that the spinel structure of Co(Al,Si)-oxide films is preserved at least on the scale of short-range interactions detected with IR spectroscopy. In addition to this, sulphate (SO42−) ions are retained in the structure of cycled films heat-treated at 500 °C. The role of order-disorder transitions of sulphate ions present in cycled films is discussed with respect to their influence in enhancing the speed and degree of coloring/bleaching changes of electrochromic Co(Al,Si)-oxide spinel films.

Sb:SnO2 films (body resistance 1.2 X 10-2 (Omega) cm) which were deposited by dip-coating technique via the sol-gel route using SnCl4(DOT)5H2O and SbCl3 precursors have been found to exhibit mixed electronic conductivity and ion-storage characteristics. The Li+ and H+ ion (de)insertion properties of the films were determined from the cyclic voltammetric (CV) measurements from solvents containing LiClO4 (0.1 M) in acetonitrile or water, LiOH (0.1 M) and HClO4 (0.001 - 0.01 M). The particle grain size of Sb:SnO2 and SnO2 films has been determined from the XRD measurements and was found to be larger for undoped (55 - 71 angstroms) than for the Sb doped films (46 - 58 angstroms). The Sb:SnO2 films exhibit effective charges per film thickness (Q(deint)/d) in the range 0.01 - 0.02 mC/cm2nm and outrange by about 3 times the Q/d values obtained for undoped films. Combining the CV results with the in-situ spectroelectrochemical measurements it was concluded that the intercalation process of Li+ ions in Sb:SnO2 films is governed by the layer charging of the inner grain surfaces which overwhelms the underlaying redox changes involving the Sn4+ ions. The performance of the transmissive electrochromic device made of WO3/H3PO4-polyvinyl alcohol (PVA)/Sb:SnO2 was tested and the results presented and discussed.

Thin iron oxide films (69–500 nm) were deposited by the dip-coating method from iron-ion-containing sols which had been made from an FeCl3·6H2O precursor precipitated with ammonium hydroxide. Homogeneous sols were obtained after peptization of precipitates with the addition of acetic acid (∼ 60 mol.%) and no organics were added in order to adjust the sol viscosity for depositing the xerogel film. In situ UV—visible spectroelectrochemical measurements revealed that films heat treated in the temperature range 200–350°C exhibited intensive bleaching in 10−3 M LiOH, KOH and NaOH electrolytes at cathodic potentials (−1.45 V) and became coloured again at anodic potentials (+0.6 V). The ability of films to take up Li+ is 0.9−1.1 Li+ per Fe2O3 giving rise to an intercalated charge of about 0.2 mC cm−2 per nanometre of the film thickness. This indicates that the film consists of particles of small grain size (γ-Fe2O3 (maghemite)) with dimensions < 100 Å and well-developed grain boundaries which contain OH− and other defect bonds originating from residual acetate groups. Consequently, only minor “activation” of films in base electrolytes is needed to attain reversible and steady electrochromism. Electrochromism was not observed for films heat treated at 500°C when α-Fe2O3 (haematite) with a larger grain size (∼ 270Å) is formed. The textural and structural properties of films were investigated with scanning electron microscopy, X-ray diffraction and UV—visible spectroscopic methods. The detected transverse optical and longitudinal optical modes determined with the help of Fourier transform IR reflectance measurements confirmed the homogeneous structure of films prepared at different temperatures. It was also found that the sols consist of iron oxohydroxo ions with chelated acetate units in addition to medium strong OH-O bonds, thus contributing to cross-linking of the gel and xerogel structure.

Thin solid films composed from monodispersed cupric oxide particles with average size about 0.06 μm and narrow distribution of sizes have been prepared by dip-coating technique. The thermal decomposition method has been applied for the preparation of particulate sols. Sols and corresponding gels have made from cupric acetate precursor and citric acid as chelating agent. Sols showed a tendency for gelling during 48 h when kept at 70°C. X-ray diffraction, scanning electron microscopy, thermogravimetric analysis and Fourier transform infrared spectroscopy have been found that the gel and the structural features of oxide coatings, xerogels and the corresponding intrmediate stages. It was found that the gel and xerogel consist of copper complexes with ammonia (-NH3), hydroxo (-OH) and carboxylate (-COO) moieties in the form of bridges, thus making possible an interlinkage between different copper ion complexes. Optical spectra revealed that a reddish-purple coating is produced on glass by dip-coating method. The efficiency of dip-coating procedures is high since 0.004±0.005 μm thick CuO films are obtained per dipping. A potential use of the CuO coatings on glass is in window glazing with shading properties for the luminous part of the solar radiation.

CuO thin solid coatings on glass and on stainless steel substrates have been prepared by the dip-coating technique. Sols have been made from a cupric acetate precursor using citric acid as a chelating agent. Scanning electron microscopy (SEM) was used for the determination of the structure of the coatings. These consist of particles with the narrow size distribution. The size of particles is around 0.14 micrometers . Specularly reflecting CuO films on stainless steel and glass substrates were prepared in the thickness range from 0.04 micrometers to 0.7 micrometers . The spectral selectivity of the CuO/stainless steel tandem coating was in the range as < 0.90 - 0.85 and eT > 0.10 -0.30. Due to the high refractive index of the CuO film the reflectance of the coatings was diminished by the introduction of fumed silica particles in the initial sols which gave a mat appearance to the coatings and increases their solar absorptance for 5%. The CuO coatings produced on glass exhibit a reddish-purple color with chromaticity coordinates which values change as a function of the film thickness. The structural features of the gel and xerogel from which the final oxide coating has been made are discussed on the basis of their FT-IR spectra.