ZnO, Li doped and Li,Ni co-doped ZnO powders to be later used as transparent conductive oxide (TCO) thin film were prepared by heat treatment of gels obtained from alcoholic Zn(CH 3 COO) 2 •2H 2 O, LiNO 3 •nH 2 O and NiSO 4 •6H 2 O solutions with (CH 3 CH 2 OH) 3 N as chelating agent. The properties of the powders and their thermal treatment were studied by thermogravimetric and termodifferential anlysis (TG/DTA), differential scanning calorimetry (DSC), evolved gas analysis coupled with mass spectroscopy (EGA-MS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy coupled with energy dispersive X-ray (SEM/ EDX). The as-prepared gels consisted of submicron platelet-like particles and contained zinc acetate dihydrate and hydrozincite in different amount and with different preferred orientations. During annealing the gels, zinc-acetate decomposed between 110-350 °C with the release of CH 3 COOH, acetone and CO 2 . The N content of the chelating agent was responsible for NH 3 and NO evolution. The thermal behavior of the doped 3 gels was similar, but there were also differences in the mass losses, amount of released gases.Based on TG/DTA data, ZnO powders were obtained from the gels by annealing both at 275 and 500 °C. After heating at 275 °C, the obtained powders consisted of spherical 1-2 micron grains of wurtzite. The inclusion of the dopants was successful according to EDX and cell parameter data. Thermal study of the powder annealed at 275 °C confirmed that they still contain some zinc acetate. In the case of the doped samples the mass loss was smaller, since the Li and Ni dopants catalized the composition of zinc acetate during the previous annealing at 275 °C. After annealing the gels at 500 °C, stable un-doped ZnO or doped ZnO particles were obtained.

For environmental applications, nanosized TiO2-based materials are known as the most important photocatalyst and are intensively studied for their advantages such as their higher activity, lower price, and chemical and photoresist properties. Zn or Cu doped TiO2 nanoparticles with anatase crystalline structure were synthesized by sol−gel process. Titanium (IV) butoxide was used as a TiO2 precursor, with parental alcohol as a solvent, and a hydrolysing agent (ammonia-containing water) was added to obtain a solution with pH 10. The gels were characterized by TG/DTA analysis, SEM, and XPS. Based on TG/DTA results, the temperature of 500 °C was chosen for processing the powders in air. The structure of the samples thermally treated at 500 °C was analysed by XRD and the patterns show crystallization in a single phase of TiO2 (anatase). The surface of the samples and the oxidation states was investigated by XPS, confirming the presence of Ti, O, Zn and Cu. The antibacterial activity of the nanoparticle powder samples was verified using the gram−positive bacterium Staphylococcus aureus. The photocatalytic efficiency of the doped TiO2 nanopowders for degradation of methyl orange (MO) is here examined in order to evaluate the potential applications of these materials for environmental remediation.

In the literature data, several papers reported the synthesis by various chemical or physical methods of the SrCu 2 O 2 (SCO) having possible applications in thermoelectric or completely electronic devices such as solar cells, liquid crystal displays and touch screen. A great challenge is represented by the formation of the pure SrCu 2 O 2 (SCO), due to the high labiality of the Cu valence, depending on temperature. In the present paper, the thermal behavior of Sr-Cu-O gels obtained by sol-gel (SG) or microwave (MW)-assisted SG methods was studied in order to establish the appropriate thermal conditions for pure nanostructured SrCu 2 O 2 preparation. As reagents, copper and strontium acetylacetonate in alcoholic media were used. The starting solutions were homogenized either by stirring for 2 h at room temperature or were exposed to MW for 5 min at 300 W and a frequency of 2.45 GHz. Both solutions were left to gel at room temperature. The obtained gels were investigated by scanning electron microscopy, Fourier-transform infrared spectroscopy, as well as by thermal analysis combined with evolved gas analysis (TG/DTA-MS) measurements in air, inert and reducing atmospheres. For both type of samples, a stepwise thermal decomposition of the gels was noticed in a large temperature range. In the case of samples obtained by microwave-assisted SG method, a higher number of thermal effects were registered assigned to a higher number of molecular species formed in the sample. The residues obtained by non-isothermal treatment up to 900 °C, of both type of samples, were investigated by X-ray diffraction. The results demonstrate the influence of the MW on the SG synthesis and on the thermal properties of the resulted gels. Based on the obtained results, the required thermal treatment of the gels in order to obtain convenient precursors powders for obtaining pure SrCu 2 O 2 could be proposed.

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We have explored an efficient strategy to enhance the overall photocatalytic performances of layered perovskites by increasing the density of hydroxyl group by protonation. The experimental procedure consisted of the slow replacement of interlayer Rb+ cation of RbLaTa2O7 Dion-Jacobson (DJ) perovskite by H+ via acid treatment. Two layered perovskites synthesized by mild (1200 °C for 18 h) and harsh (950 and 1200 °C, for 36 h) annealing treatment routes were used as starting materials. The successful intercalation of proton into D-J interlayer galleries was confirmed by FTIR spectroscopy, thermal analyses, ion chromatography and XPS results. In addition, the ion-exchange route was effective to enlarge the specific surface area, thus enhancing the supply of photocharges able to participate in redox processes involved in the degradation of organic pollutants. HLaTa_01 protonated layered perovskite is reported as a efficient photocatalyst for photomineralization of trichloroethylene (TCE) to Cl− and CO2 under simulated solar light. The enhanced activity is attributed to combined beneficial roles played by the increased specific surface area and high density of hydroxyl groups, leading to an efficiency of TCE mineralization of 68% moles after 5 h of irradiation.

Mesoporous silica materials are promising nanocarriers for the development of drug delivery systems. In this study, the influence of pore size, volume, surface area, and doping the silica framework on the release kinetics of a model drug, metoprolol, has been studied. 20% or 50% wt. therapeutic agent was loaded into the carrier mesopores through incipient wetness impregnation. The carriers and drug-loaded samples have been characterized by small-and wide-angle X-ray diffraction, FT-IR spectroscopy, scanning electron microscopy, and nitrogen adsorption-desorption isotherms. The in vitro release profiles have been fitted using a threeparameter kinetic model and they have been explained in terms of the release rate during the burst and sustained release stages and the fraction of drug molecules released during the burst stage. The silica framework doping with aluminum was found to decrease the amount of drug released in the burst stage, without affecting the other kinetic parameters. The therapeutic agent release rates depend mainly on the pore size and volume of the mesoporous carriers and drug-loaded samples.