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Nanocrystalline bismuth orthoferrite (BiFeO3) was prepared by soft chemistry. The hydroxide coprecipitation method was shown to influence the formation of nanocrystalline bismuth orthoferrite. Synthetic conditions were determined to prepare nanocrystalline BiFeO3 free of other phases of the Bi2O3–Fe2O3 system with a narrow crystallite-size distribution and the smallest crystallite size of about 6–7 nm.

Transition-metal oxide nanostructured materials are potentially attractive alternatives as anodes for Li ion batteries and as photocatalysts. Combining the structural and thermal stability of titanium oxides with the relatively high oxidation potential and charge capacity of molybdenum(VI) oxides was the motivation for a search for approaches to mixed oxides of these two metals. Challenges in traditional synthetic methods for such materials made development of a soft chemistry single-source precursor pathway our priority. A series of bimetallic Ti-Mo alkoxides were produced by reactions of homometallic species in a 1:1 ratio. Thermal solution reduction with subsequent reoxidation by dry air offered in minor yields Ti2Mo2O4(OMe)6(OiPr)6 (1) by the interaction of Ti(OiPr)4 with MoO(OMe)4 and Ti6Mo6O22(OiPr)16(iPrOH)2 (2) by the reaction of Ti(OiPr)4 with MoO(OiPr)4. An attempt to improve the yield of 2 by microhydrolysis, using the addition of stoichiometric amounts of water, resulted in the formation with high yield of a different complex, Mo7Ti7+xO31+x(OiPr)8+2x (3). Controlled thermal decomposition of 1–3 in air resulted in their transformation into the phase TiMoO5 (4) with an orthorhombic structure in space group Pnma, as determined by a Rietveld refinement. The electrochemical characteristics of 4 and its chemical transformation on Li insertion were investigated, showing its potential as a promising anode material for Li ion batteries for the first time. A lower charge capacity and lower stability were observed for its application as an anode for a Na ion battery., Controlled decomposition of a structurally characterized Ti-Mo oxo-alkoxide precursor offered an approach to the new ternary oxide TiMoO5, showing promising characteristics as an anode material for Li ion batteries.

A new gadolinium diphosphate [HGdP2O7 · 2 H2O] · NH3 was synthesized via a soft chemistry route from evaporation of aqueous solution. It crystallizes in the space group Pī with Z = 2 and the follow...

The synthesis of NaYF 4 compounds via the “soft chemistry” of sulfide precursors (a simple Y 2 S 3 and a complex NaYS 2 ) was performed. Hydrofluoric acid solution (HF) at a concentration of 3–45% and different contents of a saturated aqueous solution of sodium fluoride that was acidified by hydrofluoric acid (NaF + HF) were used as fluorinating components. When the fluorination proceeded using different concentrations of hydrofluoric acid, yttrium fluoride (YF 3 ) formed. NaYF 4 was obtained via different synthesis conditions as a mixture of cubic and hexagonal phases in nanoparticle dimensions (α=30–100 nm, β=28–60 nm).

Frequent organic pollution threatens people and the environment. Achieving rapid on-site adsorption and removal of pollutants is therefore of great significance to quickly alleviate pollution and reduce harm to life and the environment. In this study, we used organic covalent, supramolecular self-assembly and soft chemistry to construct a magnetically separable ethanolamine (AE)-functionalized graphene adsorption material (MAEGO). Due to synergy between AE and Fe3O4 nanoparticles, the adsorption active centers generated in MAEGO are highly exposed, which greatly improves the adsorption and migration of pollutants. In only five minutes, the adsorption capacities of MAEGO for tetracycline (TC), levofloxacin, methylene blue and methyl orange were 315.25, 229.53, 500 and 257.14 mg/g, respectively. The corresponding pollutant removal rates were 63.20%, 49.74%, 100% and 45.33%, respectively. When the adsorption of TC reached equilibrium (1440 min), the removal rate was 97.80%. The adsorption data fitted the pseudo-second-order and Langmuir models well. MAEGO is an efficient and promising adsorbent for rapid removal of organic pollutants.

α, β, γ, and δ polymorphs of 4.6–4.8 eV wide band gap Ga2O3 photocatalysts were prepared via a soft chemistry route. Their photocatalytic activity under 254 nm UV-C light in the degradation of gaseous toluene was strongly depending on the polymorph phase. α- and β-Ga2O3 photocatalysts enabled achieving high and stable conversions of toluene with selectivities to CO2 within the 50–90% range, by contrast to conventional TiO2 photocatalysts that fully deactivate very rapidly on stream in similar operating conditions with rather no CO2 production, no matter whether UV-A or UV-C light was used. The highest performances were achieved on the high specific surface area β-Ga2O3 photocatalyst synthesized by adding polyethylene glycol (PEG) as porogen before precipitation, with stable toluene conversion and mineralization rate into CO2 strongly overcoming those obtained on commercial β-Ga2O3. They were attributed to favorable physicochemical properties in terms of high specific surface area, small mean crystallite size, good crystallinity, high pore volume with large size mesopore distribution and appropriate surface acidity, and to the possible existence of a double local internal field within Ga3+ units. In the degradation of hydrogen sulfide, PEG-derived β-Ga2O3 takes advantage from its high specific surface area for storing sulfate, and thus for increasing its resistance to deactivation and the duration at total sulfur removal when compared to other β-Ga2O3 photocatalysts. So, we illustrated the interest of using high surface area β-Ga2O3 in environmental photocatalysis for gas-phase depollution applications.

We report a novel soft chemical synthesis method, water assisted solid state reaction (WASSR) method. This method is very simple and can synthesize many ceramic materials just by storing or mixing raw materials added a small amount of water in a reactor at low temperature below 373 K. For example, well-crystalline SrMoO4 was obtained using the WASSR method.

Lithium–vanadium Li x V2O5 (x = 0.1–0.3) bronzes are synthesized by solid-phase and soft chemistry methods. Their electrical properties are studied. Cells with an Li x V2O5 cathode and a solid or liquid lithium anode are subjected to electrochemical cycling. The lithium–vanadium bronzes synthesized by the soft chemistry method are shown to have higher electrochemical characteristics.

Considering the inferior rate capability of conversion-type transition-metal sulphides (TMSs) caused by severe volume expansion and poor electronic conductivity, a composite of perchlorate ion (ClO4−) doped polypyrrole (PPy) coated ZnS spheres (denoted as ZnS@d-PPy) has been synthesized via a soft chemistry method. Benefiting from the improved conductivity, the protection of the PPy coating and ClO4− doping, ZnS@d-PPy exhibits decent cycling performance (419 mA h g−1 after 30 cycles at 100 mA g−1) and superior rate capability (203 mA h g−1 at 4 A g−1), which is enhanced by pseudocapacitance when being applied in sodium-ion batteries (SIBs).

International audience; An aqueous synthetic route at 95 °C is developed to reach selectively three scarcely reported vanadium oxyhydroxides. Häggite V2O3(OH)2, Duttonite VO(OH)2, and Gain’s hydrate V2O4(H2O)2 are obtained as nanowires, nanorods, and nanoribbons, with sizes 1 order of magnitude smaller than previously reported. X-ray absorption spectroscopy provides evidence that vanadium in these phases is V+IV. Combined with FTIR, XRD, and electron microscopy, it yields the first insights into formation mechanisms, especially for Häggite and Gain’s hydrate. This study opens the way for further investigations of the properties of novel V+IV (oxyhydr)oxides nanostructures.

A new polymorph of potassium intercalation compound of 3R-Nb1.1S2 with chemical composition K0.77Nb1.1S2 was synthesized for the first time by a facile solution-phase method. Its structure was comprehensively characterized by powder XRD and high-resolution TEM. Furthermore, its hydrated derivatives KxNb1.1S2• yH2O were synthesized via soft chemistry strategy using etching agents of ethanol, water and an I2/CH3CN solution, respectively. Superconducting transition at 4.0 K was observed for the product with the doping content x=0.12. While superconductivity disappeared in products KxNb1.1S2• yH2O (x=0.48 and 0.35) which displayed a metal-to-semiconductor transition at low temperature. In addition, the XPS analysis revealed an upward shift in the Fermi level in K0.12Nb1.1S2• yH2O compared with the host or K0.77Nb1.1S2.

The efficiency of various methods for the preparation of titania-based nanocomposites, Fe2Ti2O7 and Fe2TiO5, starting from colloid solutions of hydroxy iron species and the products of titanium tetraisopropoxide hydrolysis was evaluated. The effect of the conditions of synthesis (Fe3+/Ti4+ concentration ratios of 1 and 2, pH of the reaction medium, temperature, and sonication) on the composition, structure, and properties of the nanocomposites formed was elucidated; the effect of the phase composition on the photocatalytic activity of materials formed during the liquid-phase synthesis was established. The resulting materials were studied by electron microscopy, low-temperature adsorption, IR spectroscopy, and powder X-ray diffraction.

WO 3 photoanodes have been constructed by a simple soft chemistry procedure that produced efficient mesoporous nanocrystalline films. These photoanodes absorbed visible light and could be efficiently employed for photoelectrochemical hydrogen production under electric bias. The current increased and the rate of hydrogen production more than tripled in the presence of a small quantity of ethanol showing that such photoanodes may be successfully used in alternative photoelectrochemical installations for solar fuel production by consumption of organic wastes.

Crystals of HTmP2O7·3H2O were prepared via a soft chemistry route. Its crystal structure was solved from single-crystal diffraction data. The compound crystallises in the triclinic space group P-1, with the unit cell parameters: a = 6.3724(4) A, b = 6.8224(3) A, c = 9.7299(5) A, α = 82.039(4) °, β = 79.758(5) °, γ = 88.200(4) ° and Z = 2. In its lamellar structure, edge-sharing polyhedra of eightfold coordinated Tm(III) form chains along [010]. These chains are joined in turn to each other using pyrophosphates O-P-O bridges. A network of O H…O hydrogen bonds reinforces the cohesion of the structure. The IR spectrum of HTmP2O7·3H2O is interpreted on the basis of characteristic vibrations of PO3 group, POP bridge, and in addition, H2O. The optical properties of HTmP2O7·3H2O were analysed with UV–Vis. The spectrum is characterized by bands corresponding to the transitions starting from the 3H6 ground state to the different higher levels 1G4, 3F2, 3F3, 3H5, and 3F4 of Tm3+ ion.

Nanostructured silica hybrid materials have been synthesized via soft chemistry way, by the incorporation of functional 1,2,4-triazole components into a silica network, using a perhydropolysilazane (PHPS) as a silica source and 1,2,4-triazole components as templates. The compositions, morphological and textural properties of the as-synthesized samples have been studied by 13C and 29Si CP MAS NMR, FTIR and SEM. The spectroscopy results suggest that the organic moieties have been chemically linked to the silica skeleton leading to hybrid materials in which Si–N, Si–O and Si–S bridges are created. Nitrogen adsorption-desorption analysis (BET) shows that the surface area varied between 385 and 425 m2 g−1. The 29Si CP-MAS NMR displays signals between -70 and -120 ppm corresponding to Q2, Q3 and Q4 units. The optical properties have been studied also by UV–visible diffuse reflection spectroscopy and photoluminescence (PL). This study reveals that the direct gap energies varied between 0.71 and 2.53 eV. Photoluminescence shows that the silica nanohybrids are suitable to the emission of blue light with wavelength (λem) values of about 470-480 nm. The PL emission results also from some silicon/oxygen-related defect species.

A new (C8H12N)SnCl3 crystal of the general formula AMX3 was grown by soft chemistry method. X-ray study shows that the crystal crystallized in a monoclinic system with the space group P21/a. The structure was solved by Patterson method and refined to a final value of R = 0.0304 for 1157 independent observed reflections. The cohesion and the stability of the atomic arrangement result from the N–H … Cl hydrogen bonds between (C8H12N)+ cations and isolated (SnCl3)– anions. At high temperature this compound exhibits a structural phase transition at 340 K. This transition has been characterized by differential scanning calorimetric and impedance spectroscopy. The impedance data were well fitted to an Rp//CPE equivalent electrical circuit model. The close values of activation energies, obtained from the thermal behavior of the conductivity and the relaxation time confirm the presence of a hopping transport mechanism.

CuFe 2− x Cr x O 4 spinel (0≤ x ≤2) powders were synthesized by a soft chemistry method—the gluconate multimetallic complex precursor route. The complex precursors were characterized by elemental chemical analysis, infrared (IR) and ultraviolet–visible (UV–vis) spectroscopy, thermal analysis and Mossbauer spectroscopy. The oxide powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), IR, Raman and Mossbauer spectroscopy. It was shown that the structure, morphology and magnetic properties of the obtained spinel powders depend on the concentration of Cr 3+ ion. The XRD of the chromium substituted copper ferrite powders calcined at 700 °C/1 h indicated the formation of a cubic spinel type structure for x =0.5, 1.0 and a tetragonal structure for x =0, 0.2, 2. The crystallite size ranged from 19 nm to 39 nm. The Mossbauer spectroscopy revealed the site occupancy of iron ions, relative abundance and internal hyperfine magnetic fields in both tetrahedral and cubic CuFe 2− x Cr x O 4 spinels.

The various gas sensors were designed for detection of different gases in the air using different oxides and impurities [13]. For example the manufacturing of ammonia sensors on the basis of CuxS-micro-porous-Si structure includes manufacture of micro-porous silicon, drawing on it of SiO2 isolating layer, and then the CuxS layer [4, 5]. The special equipment for all these processes is needed. More usable method for sensor production is so-called soft chemistry or sol– gel synthesis [6, 7]. Sol–gel process can be used to produce a wide range of various compounds (usually oxides) including their thin films, nanopowders, fibers, glasses, ceramics, organic-inorganic hybrids, and so on. The sol–gel process can be characterized by a series of discrete steps. Step 1: formation of the “sol” i.e. colloidal suspension of solid particles (usually salts of necessary materials) in a liquid (solvent for necessary materials). Step 2: gelation resulting from the formation of an oxide network (the gel) by a polycondensation that results in a dramatic increase in the viscosity of the solution. This network structure may result from physical or chemical bonds, as well as crystallites or other junctions that remain intact within the extending fluid. Step 3: formation of a xerogel a solid formed from a gel by drying usually in air atmosphere. As a result all solvent components that are not bonded with oxide network abandon the gel. A lot of various vanadium hydrated compounds were synthesized by using this simple method [8]. The sol–gel technology is also widely used for the production of the humidity sensors based on the vanadium hydrated compounds [9, 10]. The chemical composition of produced materials was investigated using the X-ray photoelectron spectroscopy (XPS) method. XPS is known as the surface analysis method which provides the direct information on the species concentration and their valence states. So we use these features of the method for studies of the surface composition of investigated xerogels. In the present paper, we introduce the ammonia gas sensor based on the vanadiummolybdenum-ammonium oxide hydrate that could operate at the room temperature area.

In this work, a series of mesoporous alumina materials exhibiting high surface areas have been synthesized, characterized and used in the preparation of CO 2 sorbents. The mesostructured powders were prepared through a soft chemistry route, employing aluminum tri-sec-butoxide-derived sol precursors in the presence of different surfactants. Structural and microstructural characterization techniques showed that γ-Al 2 O 3 powders were composed of nanocrystals, and the samples presented high surface area values (238.6–496.7 m 2 g −1 ) produced by a high mesostructured order, depending on the surfactant used as structure-directing agent. Based on the textural features, selected γ-Al 2 O 3 materials were employed as supports for the preparation of potassium-based sorbents for CO 2 capture at low temperatures (30–80 °C). Potassium-loaded alumina supports were synthesized by a wet impregnation method, and the CO 2 sorption tests were conducted via thermogravimetric analysis. The surface area and pore volume of the potassium-impregnated supports experienced a noticeable reduction, in comparison with the original values, suggesting the inclusion of potassium inside the support porosity. Nevertheless, the sorbents showed excellent reactivity; in fact, the potassium/γ-Al 2 O 3 sorbent prepared with 40 wt% potassium content had a maximum CO 2 capture capacity of 4.03 mmol CO 2 /g sorbent at the relatively low temperature of 80 °C in the presence of water vapor. These results suggest that both the potassium content and textural properties of mesostructured γ-Al 2 O 3 supports could provide an enhancement of the CO 2 absorption properties.

While the soft chemistry of layered alkali metal oxides is adequately understood, the effect of the post-synthesis thermal treatment on their structure, composition, and properties has been underexplored. In this article, we thoroughly investigated the bulk and surface modifications of K0.8M0.4Ti1.6O4 (M = Ni, Cu, Zn) lepidocrocite titanate thermally treated within 200 °C above its synthetic temperature under air. This practice was typically employed in e.g., specimen fabrication for physical property measurements. We observed the expansion of the interlayer distance (b/2) accompanied by a reduction in layer charge density. These findings can be explained by the deintercalation of interlayer K+ ions and the loss of intralayer Ti, M, and O species. Meanwhile, the enrichment of potassium and carbonate on the surfaces was evident. The slight differences in dielectric properties of the pellets thermally treated at different temperatures were attributed to the combination of bulk and surface modifications. At 103 Hz and RT-250 °C, the maximum dielectric constants e'max of ∼104 with the dielectric loss (tan δ) ∼0.9-1.5 were obtained for K0.8Zn0.4Ti1.6O4.

Filled tetrahedral semiconductors are a rich family of compounds with tunable electronic structure, making them ideal for applications in thermoelectrics, photovoltaics, and battery anodes. Furthermore, these materials crystallize in a plethora of related structures that are very close in energy, giving rise to polytypism through the manipulation of synthetic parameters. This Minireview highlights recent advances in the solution-phase synthesis and nanostructuring of these materials. These methods enable the synthesis of metastable phases and polytypes that were previously unobtainable. Additionally, samples synthesized in solution phase have enhanced thermoelectric performance due to their decreased grain size.

Calcium manganate Ruddlesden–Popper phases Ca2MnO4–δ were prepared by soft chemistry and treated with acid to extract a part of the calcium ions. Combined structural, morphological and spectroscopic analyses by XRD, SEM/EDX, TEM and Raman revealed an amorphization of the treated surface with a preserved inner crystalline phase in the core of the particles. The inner part of the particles consists of Ca2MnO4–δ and the outer part of hydrated amorphous manganese oxide MnO2·xH2O. Although pristine Ca2MnO4–δ is not electrochemically active, electrochemical characterization of the acid-treated powders shows a significant change in capacity that correlates to the amount of extracted calcium. The cycling stability of the Ca2 + extracted compounds was improved by more than a factor of 10 in comparison to pure MnO2·xH2O. The acid-treated Ca2MnO4–δ showed enhanced capacity retention of up to 50% after 70 cycles compared to 4% for bare MnO2·xH2O due to its crystalline core.

Lanthanum zirconate with a pyrochlore structure exhibits interesting thermal and structural properties for thermal barrier coating applications operating at high temperature. This study focused on the synthesis of La2Zr2O7 powders by soft chemistry (citrate, coprecipitation, and sol–gel methods), and the effects of the solvent and the nature of the precursors used on the powder properties were investigated. The nature of the counter-cation influenced the structural phase of the compound. A low polarizable counter-cation (chloride) permitted the elaboration of a pyrochlore structure within a larger range of parameters compared with highly polarizable counter-cations (nitrate and acetate). Moreover, the nature of the solvent, and specifically the strength of the interactions within it, had an impact on the particle size. Specifically, the use of water, which is a solvent with strong interactions, led to a smaller particle size than the use of ethanol, which has weaker interactions. Based on these results, the crystalline phase of the powders can be predicted as a function of the precursor and the solvent used for the different synthesis routes, and the particle size can be used to evaluate the reactivity of the powders.

The BaF2-ScF3 system is studied using coprecipitation from aqueous solutions. Compound Ba3Sc2F12 is found to form over a wide range (10–60 mol %) of scandium concentrations in the initial solution. At higher scandium concentrations in solution, a new phase of provisional composition BaSc2F8 · 2H2O (hexagonal system, a = 9.6346 A, c = 4.0483 A) was obtained. Scandium fluoride hydrolysis is not observed by energy-dispersive X-ray analysis.

The SrFeO 2 F oxyfluoride was prepared through a low temperature, multistep synthetic route starting with the SrFeO 3− x perovskite via the SrFeO 2 infinite layer intermediate phase. In the final step SrFeO 2 F was formed by reacting SrFeO 2 with XeF 2 at 150 °C. In spite of utilizing an intermediate with layered ordering of oxygen vacancies, disordered SrFeO 2 F was synthesized. Rietveld refinement of synchrotron powder diffraction data did not reveal any signs of tetragonal distortion predicted by DFT calculations for SrFeO 2 F with layered O/F ordering. Significantly, the magnetic properties observed are drastically different from those reported earlier in the literature indicating that the properties of O/F disordered phases depend on the degree of short range ordering. Mossbauer spectroscopy measurements revealed the predominance of cis fluorine configuration in FeO 4 F 2 polyhedra, confirming a difference in local Fe coordination in comparison with O/F disordered SrFeO 2 F.

Substitution of cations in metal oxides result in differences of materials characteristics. Substitution resulting in isostructural materials is not easy. In this work, Cu has been used as the substitution element for Zn in Zinc oxide. The Zn(1-x)CuxO (x=0.01, 0.02, 0.03, 0.04, 0.05) materials were prepared via a simple soft chemistry method without using any chelating agents. Results showed that some of the samples are pure but the heavily doped samples contain a very small amount of CuO as an impurity. XRD and microscopy results agree with each other.

Nanodimensional Fe(III)-TiO2 crystalline particles have been obtained by the soft chemistry technique in an aqueous solution without calcination. The crystallization of the products of hydrolysis of titanium dioxide used as a precursor was carried out by boiling in the presence of acidic peptizing agents, which facilitated the temperature dehydration of hydroxo and oxo compounds. A phase of nanodimensional magnetite was used as a center of crystallization, which resulted in the doping of the crystalline lattice of TiO2 of an anatase modification. The powders and films that formed from solutions showed high photocatalytic activity under the action of visible light. According to morphological analysis, nanodimensional Fe(III)-TiO2 crystalline particles possess a narrow size distribution of pores and a high specific surface area.

Ultrathin Ag2Mo3O10·2H2O nanowires (NWs) were synthesized by soft chemistry under atmospheric pressure from a hybrid organic-inorganic polyoxometalate (CH3NH3)2[Mo7O22] and characterized by powder X-ray diffraction, DSC/TGA analyses, FT-IR and FT-Raman spectroscopies, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Their diameters are a few tens of nanometers and hence much thinner than that found for silver molybdates commonly obtained under hydrothermal conditions. The optical properties of Ag2Mo3O10·2H2O NWs before and after UV irradiation were investigated by UV-vis-NIR diffuse reflectance spectroscopy revealing, in addition to photoreduction of Mo(6+) to Mo(5+) cations, in situ photogeneration of well-dispersed silver Ag(0) nanoparticles on the surface of the NWs. The resulting Ag@Ag2Mo3O10·2H2O heterostructure was confirmed by electron energy-loss spectroscopy (EELS), X-ray photoelectron spectroscopy (XPS), and Auger spectroscopy. Concomitant reduction of Mo(6+) and Ag(+) cations under UV excitation was discussed on the basis of electronic band structure calculations. The Ag@Ag2Mo3O10·2H2O nanocomposite is an efficient visible-light-driven plasmonic photocatalyst for degradation of Rhodamine B dye in aqueous solution.

We have developed a vanadyl phosphate/tetraethylorthosilicate (VPO/TEOS) nanocomposite comprised of silicate chains interleaved with VPO layers, prepared by using an n -alkylamines such as octylamine as the structure directing agent. The nanocomposites were synthesized by reacting amine-intercalated vanadyl phosphate with tetraethylorthosilicate via the soft chemistry approach. The synthetic procedure encompassed the exfoliation of the layered vanadyl phosphate as well as the reorganization of this exfoliated solid into a mesostructured lamellar phase with the same V–P–O connectivity as in the original matrix. TEOS incorporation into the vanadyl phosphate was achieved by expanding the lamellar structure with n -alkylamine (Δ d = 13 A with n -octylamine). The specific surface area increased from 15 m 2 g −1 in the vanadyl phosphate matrix to 237 m 2 g −1 in VPOcT, and the isotherm curves revealed the characteristic hysteresis of mesoporous materials. Upon thermal treatment up to 500 °C, the surface area increased to 837 m 2 g −1 , which is suitable for catalytic purposes.

Here we report the synthesis and some physical properties of superoxides CuYO2.51 and CuYO2.25 prepared from the delafossite CuYO2 respectively by thermal oxidation at 380 °C under O2-flow and soft chemistry in NaBrO (5N) solution and their applications as catalysts for solar energy conversion in a chemical H2 evolution, upon visible light. The oxygen insertion was accompanied by partial oxidation of Cu+ lattice. For CuYO2.25 , the chemical analyses as well as magnetic data reveal the presence of mixed valent states containing at least formally an equal number of Cu+ and Cu2+. In air, CuYO are thermally stable up to 500 °Cabove wich they undergo . an irreversible 2+X conversion into CuY2O5. The oxides are chemically stable in basic media and under illumination, they are stabilizsd by hole consumption reactions involving SO32- and S2- as holes scavengers. The flat band potentials lying between 0,17 and 0,17 eV, are located above the H2O/H2 level, leading to a spontaneous H2- evolution. The rate of H2-formation is altered by the oxygen insertion and the best photoactivity is obtained over CuYO2.25 immersed at 0.025 M sulfide S2- solution. A photoelectrochemical study is reported for comparison with photoactivity results.

The synthesis of complex metal-oxide phases is typically performed at high temperature to overcome the considerable energetic barriers to solid-solid diffusion. However, these ceramic synthesis strategies often struggle to prepare homogeneous samples free from impurity phases, and in general cannot be utilized to prepare metastable phases.By applying low-temperature 'soft chemistry' via the use of precursor phases or solvothermal and flux synthesis routes, more homogeneous samples can be prepared. In addition by utilizing the high mobility of particular chemical species within extended metal-oxide lattices, low-temperature topochemical (structure-conserving) reactions can be performed to yield metastable product phases. © 2013 Elsevier Ltd. All rights reserved.

We describe the soft chemistry synthesis of amine-templated gallium chalcogenide nanotubes through the reaction of gallium(III) acetylacetonate and the chalcogen (sulfur, selenium) using a mixture of long-chain amines (hexadecylamine and dodecylamine) as a solvent. Beyond their role as solvent, the amines also act as a template, directing the growth of discrete units with a one-dimensional multilayer tubular nanostructure. These new materials, which broaden the family of amine-stabilized gallium chalcogenides, can be tentatively classified as direct large band gap semiconductors. Their preliminary performance as active material for electrodes in lithium ion batteries has also been tested, demonstrating great potential in energy storage field even without optimization.

In the present work protonic forms of layered n=1 Ruddlesden-Popper oxides HLnTiO4 (Ln=La, Nd) were used as starting point for synthesis of three series of the perovskite-like compounds. Characterization by SEM, powder XRD and TGA has been performed for the determination of the structure and composition of synthesized oxides.

LiNi1 − y − zCoyMnzO2 (y = 0.25, 0.35, 0.5, 0.6; z = 0.1, 0.2) cathode materials were synthesized by a soft chemistry, EDTA-based method. Among studied oxides, LiNi0.65Co0.25Mn0.1O2 compound possesses the best electrical conductivity. Higher amount of Mn in the samples worsen transport properties of these oxides. The observed decrease of the electrical conductivity of the compounds during deintercalation process can be correlated with a decrease of the effective charge carriers concentration. Additional, small Cu doping, realized for LiNi0.63Cu0.02Co0.25Mn0.1O2 composition, allows to retain high electrical conductivity during deintercalation process in this oxide, with relatively wide chemical stability range being from 1 to 0.35 mol of lithium. Additionally, in this paper the results of measurements of electrochemical performance of studied cathode materials are presented. During the first 10 cycles the best performance was observed for Li/Li+/LixNi0.63Cu0.02Co0.25Mn0.1O2 cell, which can be connected to the improved kinetics of the intercalation process related to a high lithium diffusivity in the cathode material.

Acetate-citrate precursors were applied to synthesize amorphous gelatinous calcium barium selenate with molecular formula (Ca0.5Ba0.5Se2O5). The gel-product was sintering at 800°C for 2 hrs then well characterized by X-ray diffraction, SEM and EDX elemental analyses and proved that the product Ca0.5Ba0.5Se2O5 is mainly belong to AB2X5-type structure with average grain size ranged in between 1.2–3.8 μm. A visualized study was constructed depending upon SEM and 3D-AFM experimental data to confirm the the microstructure morphological features of calcium-barium selenate surface.

Pigeon blood red powder samples of SnO were synthesized via a soft chemistry route. A precipitate was obtained from a freshly prepared SnCl2 solution containing phosphorus acid by adding ammonia until a pH value of 4.9 is reached. Heating of the mixture at 95 °C leads after 5 d to microcrystalline powders of red SnO. The crystal structure was solved and refined from X-ray powder diffraction data (Cmc21; a = 5.0045(3) A, b = 5.7457(3) A, c = 11.0485(5) A, Z = 8). Red SnO crystallizes in a new structure type. Characteristic building units are double layers of tin and oxygen atoms. The tin atoms are surrounded by four oxygen atoms with distances ranging from 2.04 A to 2.67 A, and the highly asymmetric coordination around the Sn2+ ions indicates the presence of a stereochemically active lone pair. LMTO band structure calculations show that the red modification of SnO is an insulator. The electronic structures of red SnO and the zero band gap semiconductor black SnO are compared. The lone pairs of the tin atoms are visualized via the electron localization function.

α-MnO2 nanorods were obtained by a fast redox transformation of aqueous solution of potassium permanganate. The formation mechanism of 1D nanocrystals proceeds via a first pH- and temperature sensitive stage followed by cation/anion control of the nanorod growth. A high surface area and nanostructuring allowed to achieve superb catalytic activity in a CO oxidation process compared to a conventionally prepared manganese dioxide.

A new Mn3+ hydrogenophosphate LiMn(H2P2O7)2 was synthesized, using a soft chemistry method. The ab initio structure resolution of this phase shows that it consists of infinite chains [MnH4P4O14]∞, built up of corner-sharing MnO6 octahedra and P2O5(OH)2 diphosphate groups. The cohesion between the chains is ensured by Li+ cations and hydrogen bonds. This compound is paramagnetic and Mn3+ is in high spin (H.S.) configuration. The impedance plots show that this hydrogenophosphate is a modest ionic conductor with activation energy of 0.8 eV and a conductivity reaching 10–6 S·cm–1 at 320 °C.

In this paper, we report a strategy for preparing an inorganic zinc titanate precursor by applying a chemical bath deposition method (CBD) to ZnO nanocrystals in an aqueous layered titanate colloid. The zinc titanate precursor, obtained as a precipitate, undergoes profound changes under the influence of elevated temperatures in normal atmospheric conditions and allows us to obtain zinc titanate ZnTiO3 with a rhombohedral symmetry. Investigations of its dielectric properties enabled us to determine a dielectric permittivity (ɛ) of 25, a low loss factor tan(δ)

Electrochromic nickel oxide (Ni(1−x)O) thin films and composite nickel oxide–polyaniline (Ni(1−x)O–PANI) thin films were prepared by a new peroxo soft chemistry route based on a nickel acetate ionic solution precursor. The ionic solution was synthesized from nickel acetate, urea and hydrogen peroxide. The deep green colloidal solution for the preparation of nickel oxide films was prepared by digestion of ionic solution with ethanol. The polyaniline, PANI, was in-situ polymerized from aniline molecular precursor in the second step and then added to the colloidal nickel oxide sol to obtain a deep green–brown colloidal solution appropriate for deposition of composite Ni(1−x)O–PANI films. Thin xerogel films were deposited by a dip-coating technique on FTO glass substrates and heat treated at 300 °C. Nano-crystalline non-stoichiometric Ni(1−x)O and composite Ni(1−x)O–PANI films were formed. The as-deposited Ni(1−x)O films exhibited a gray–black color, whereas the composite Ni(1−x)O–PANI films were almost transparent. The electrical, optical and electrochromic properties of all films were examined. The results showed that composite Ni(1−x)O–PANI films exhibit superior properties over plain Ni(1−x)O films. This confirmed the role of PANI, which was selected to improve the electrical and optical properties of nickel oxide films. The electrochromic properties of gray–black Ni(1−x)O and almost transparent composite Ni(1−x)O–PANI films were tested in a 1 M LiClO4/propylene carbonate electrolyte. Spectroelectrochemical measurements showed charge capacities above 15 mC/cm2 and coloring/bleaching changes from gray–black to transparent of more than 70%. Such changes are sufficient to enable the preparation of efficient electrochromic cells consisting of an anodic nickel oxide based counter electrode and cathodic WO3 electrochromic layer.

The half-metallic ferromagnet K(2)Cr(8)O(16) with the hollandite structure has been chemically modified using soft chemistry methods to increase the average oxidation state of chromium. The synthesis of the parent material has been performed under high pressure/high temperature conditions. Following this, different redox reactions have been carried out on K(2)Cr(8)O(16). Oxidation to obtain potassium-de-inserted derivatives, K(2-x)Cr(8)O(16) (0 ≤x≤ 1), has been investigated with electrochemical methods, while the synthesis of sizeable amounts was achieved chemically by using nitrosonium tetrafluoroborate as a highly oxidizing agent. The maximum amount of extracted K ions corresponds to x = 0.8. Upon oxidation the hollandite structure is maintained and the products keep high crystallinity. The de-insertion of potassium changes the Cr(3+)/Cr(4+) ratio, and therefore the magnetic properties. Interestingly, the Curie temperature increases from ca. 175 K to 250 K, getting therefore closer to room temperature.

The study of the oxidation of the “114” orthorhombic cobaltite CaBaCo4O7, using first electrochemistry and then soft chemistry based on oxidation by NaClO, has allowed a new phase, CaBaCo4O7.50, to be prepared topotactically. The structural study of this phase shows that its hexagonal structure, closely related to that of orthorhombic CaBaCo4O7, is curiously similar to that of the members of the LnBaCo4O7 series, in spite of its excess oxygen. Its magnetic study shows that this phase, like CaBaCo4O7, is ferrimagnetic with the same TC (60 K), but differently exhibits an unusual magnetic hysteresis. This exceptional behavior of CaBaCo4O7 with respect to oxidation as well as the magnetic properties of CaBaCo4O7.50 is interpreted in terms of the presence of defects due to oxidation.

Spherical Li 3 V 2 (PO 4 ) 3 /C composites are synthesized by a soft chemistry route using hydrazine hydrate as the spheroidizing medium. The electrochemical properties of the materials are investigated by galvanostatic charge–discharge tests, cyclic voltammograms and electrochemical impedance spectrum. The porous Li 3 V 2 (PO 4 ) 3 /C spheres exhibit better electrochemical performances than the solid ones. The spherical porous Li 3 V 2 (PO 4 ) 3 /C electrode shows a high discharge capacity of 129.1 and 125.6 mAh g −1 between 3.0 and 4.3 V, and 183.8 and 160.9 mAh g −1 between 3.0 and 4.8 V at 0.2 and 1 C, respectively. Even at a charge–discharge rate of 15 C, this material can still deliver a discharge capacity of 100.5 and 121.5 mAh g −1 in the potential regions of 3.0–4.3 V and 3.0–4.8 V, respectively. The excellent electrochemical performance can be attributed to the porous structure, which can make the lithium ion diffusion and electron transfer more easily across the Li 3 V 2 (PO 4 ) 3 /electrolyte interfaces, thus resulting in enhanced electrode reaction kinetics and improved electrochemical performance.

The amorphous hydrated precursor of Li1.2V3O8 was synthesized by soft chemistry method, and then heat-treated in air at several temperatures within the range 200-400 degrees C. The heat-treatment changed its morphological, structural and charging/discharging performance. The product obtained upon the treatment at 300 degrees C. consisting of uniform, rod-shaped particles, 100-150 nm in diameter and 300-800 nm in length, displayed the best electrochemical performance in aqueous LiNO3 solution. Its initial discharge capacity amounted to 136.8 mAh g(-1) at a rate of C/5, which upon 50 charging/discharging cycles decreased for only 12%. (C) 2011 Elsevier Ltd. All rights reserved.

It is shown that metastable 1T-Nb2S2C can act as a host lattice for intercalation by soft chemical methods similar to isotypic Ta2S2C. The hydrated intercalation compounds Mx(H2O) y[Nb2S2C] (M…Na, K) are prepared by ion exchange in Cux[Nb2S2C] using NaCN or KCN or by reductive intercalation into the host lattices T2S2C at pH~10 using dithionite as reducing agent. The intercalation phases are characterized by TGA and X-ray powder diffraction. Nax(H2O)y[Nb2S2C] and Nax(H2O)y[Ta2S2C] have an expanded 1T-type with two layers of co-intercalated water while in Kx(H2O)y[Nb2S2C] only one layer of water is held by the less hydrated potassium ions. Kx(H2O)y[Nb2S2C] has a 3R(Ib)-type stacking. The intercalation phases are not very stable, especially Nax(H2O)y[Nb2S2C] and Nax(H2O)y[Ta2S2C] are very quickly deintercalated by oxidation. After deintercalation colloidal suspensions are formed. Ethylene diamine is spontaneously intercalated into Nb2S2C and Ta2S2C. Nb2S2C.enx has a 3R(Ib)-type stacking similar to that of Kx(H2O)y[Nb2S2C]. Ta2Se2C is isotypic to 1T- Ta2S2C (P m1, a = 3.313(1) Å, c = 8.968(2)Å, Z = 1). Ta2Se2C does not form intercalation phases under soft chemical conditions.

A one-pot template-free solvothermal synthesis of crystalline Li4Ti5O12 nanostructures based on the “benzyl alcohol route” is introduced. The 1–2 µm sized nanostructured spherical particles are constituted of nanocrystallites in the size range of a few nm. This is the first report showing that crystalline Li4Ti5O12 can be directly obtained by soft chemistry solution routes. The as-synthesized crystalline nanostructures show good lithium intercalation/deintercalation performances at high rates (up to 30 C) and good cycling stabilities. Annealing the nanostructures at 750 °C improves the performance, which approaches the theoretical capacity of Li4Ti5O12 with no noticeable (less than 5%) capacity loss after 200 cycles.

Nanostructured ceramic oxides exhibit novel and appreciable mechanical, electrical and magnetic properties in comparison with the bulk counterparts and therefore offer many industrial applications. Most of the research in the field of nanoscience in the past two decades has been dedicated to the synthesis routes of the fine particles. This review presents an overview of the generally followed methods for the synthesis of fine ceramic oxides with special focus on the methods suitable for bulk production of fine ceramics, particularly on the methods developed by the authors. The method developed by the authors basically involves evaporation/flame pyrolysis of a precursor solution constituting the desired metal ions dispersed in a polymeric reagent (polyhydroxy-organics). Afterward the process has been improved involving metal ions complexed with a chelating agent (diethanolamine triethanolamine, inorganic acids such as citric/oxalic/tartaric acid, EDTA, etc) and simple polyhydroxy organic compound. These re...

A brief survey of chemical synthesis methods for SrTiO3 nanoparticle fabrication is presented. The principal features of microwave, mechano-chemical, coprecipitation, sol–gel, solvothermal and template methods as well as the limits of their application are described. Special attention was paid to nominally pure and transition metals doped SrTiO3 nanoparticles of 100–12 nm size, prepared by citrate method, their characterization, and dependence of lattice constant and optical band gap on particle size.