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In this paper, a new kind of high-entropy (Ba 0.2 Mg 0.2 Ca 0.2 Sr 0.2 Pb 0.2)TiO 3 oxide powder was synthesized successfully by a wet-chemical method. The effects of reaction temperature, time and pH value of hydrothermal reaction on phase and morphology of the powders were studied. The results showed that the high entropy oxide powders had perovskite structure. The morphology of the powder was significantly affected by reaction conditions. With the increase of temperature, the powder morphology changed from rod to simple cubic. Perovskite phase can be obtained only when the pH value reached above 12.5. When the reaction condition was 100–120 °C for 24 h, the rod-like powders with pure perovskite phase were obtained. However, a secondary phase Pb 5 O 8 appeared in the powders as the temperature was higher than 120 °C. Interestingly, 2 × 2 × 2 Pocket Cube-like powders with tetragonal perovskite structure were obtained by pH value of 13 when the hydrothermal reaction was at 160 °C–180 °C for 24 h. After sintering at 1200 °C for 2 h, the ceramic was completely single phase with tetragonal perovskite structure. It was almost no pores and the relative density reached 95%. [ABSTRACT FROM AUTHOR]

Using chitosan as the carbon source, F127 as the template, and sodium tripolyphosphate as cross-linking agent, a hydrogen bond and ionic bond double-driven mesoporous carbon material was prepared via the sol-hydrothermal method and its formation mechanism was discussed. According to the results from FTIR, Raman, XPS, physical adsorption analyzer, SEM, TEM, and TG-IR, the mesoporous carbon material was formed under the synergistic effect of hydrogen bond and ionic bond has a mesoporous volume of 0.44 cm3/g, a BET surface area of 262 m2/g, and possesses the ideal unimodal distribution around 2.20 nm. The mesopores are originated from the degradation of hydrophobic segment PPO of F127, and the micropores come from the gases CO 2 , CO, NH 3 , CH 4 , tetraethylene glycol dimethyl ether, and 2,6-diisopropylphenyl isocyanate produced during the degradation of prepolymers. The maximum adsorption capacity of this mesoporous carbon for tannic acid (Sips model) at 30 °C is 70.4 mg/g. [ABSTRACT FROM AUTHOR]

Nd-modified TiO2 photocatalysts have been obtained via hydrothermal (HT) and sol–hydrothermal (SHT) methods. The as-prepared samples were characterized by X-ray diffraction (XRD), BET surface area measurements, scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), luminescence spectroscopy and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of the synthesized samples was evaluated by the degradation of phenol in aqueous solution under irradiation with UV–vis (λ > 350 nm) and vis (λ > 420 nm) light, as well as by the degradation of gaseous toluene under irradiation with vis (λmax = 415 nm) light. It was found that Nd-modified TiO2 is an efficient photocatalyst for the degradation of phenol and toluene under visible light. XPS analysis revealed that the photocatalyst prepared via HT method contains a three-times higher amount of hydroxy groups at the surface layer and a two-times higher amount of surface defects than that obtained by the SHT method. The photocatalytic efficiency of phenol and toluene degradation under vis irradiation in the presence of 0.25% Nd-TiO2(HT) reached 0.62 and 3.36 μmol·dm−1·min−1, respectively. Photocatalytic activity tests in the presence of Nd-TiO2 and scavenger confirm that superoxide radicals were responsible for the visible light-induced degradation of the model pollutant in aqueous solution.

PZT antiferroelectric ceramic powder with single perovskite structure was synthesized by sol-hydro thermal method. According to the test results of the research group in the early stage, the hydrothermal reaction temperature was selected as 180 °C, the hydrothermal reaction time as 24 h, and the concentration of mineralizer KOH as 3 mol/L. The effects of the excessive value of Pb on the synthesis of PZT ceramic powder were discussed. It is found that the excessive value of Pb is too low to compensate for the loss of Pb in the reaction process. The loss of Pb at A position is easily lead to the decrease of the crystallinity of PZT powder and the incomplete crystallization of particles. With the increasing of Pb excessive value, the particle crystallization is enhanced and the crystallization is more complete. When the content of Pb increases to 10%, PZT powder with good crystallinity is obtained. Therefore, the best excessive value of Pb in this experiment is determined as 10%. [ABSTRACT FROM AUTHOR]

Vanadium oxide (VOx) possesses high-potential pseudocapacitive characteristics. But it is still unsatisfactory for supercapacitors because of the poor ionic diffusivity and electrical conductivity of VOx. Nanocrystallization can decrease the distance of ion diffusion, then improve the ionic diffusivity. Suitable carbon coating could heighten conductivity and provide ion pathways. Here we synthetized V6O13@C by a sol-hydrothermal method, then pyrolyze to form VOx@C core-shell nanorod composites. The carbon nanoshells with abundant pores on the surface of vanadium oxide improve the conductivity of the nanorod electrodes and provide sufficient ion pathways. The microstructure and electrochemical measurements reveal the V6O13@C prepared from 0.8 g V2O5 raw material under 700 °C heating possesses optimal performance. As the electrode materials of a symmetric supercapacitor, such VOx@C core-shell nanorods possess a high capacity (545 F g−1 at 0.5 A g−1, 437 F g−1 at 5 A g−1) and satisfactory cyclability (88.3% retention after 2000 cycles at 0.5 A g−1). SEM and TEM show that the V6O13@C consists of uniform-size nanorods whose diameter is 20 nm with a 7-nm-thickness carbon shell layer. The favorable electrochemical performance is stemmed from unique structural features of V6O13@C nanorods. 1D structure of nanorods could significantly cut down the ion migration process as well as improving ion diffusion kinetics. Carbon nanoshell provides the high conductivity for electron, and the pores provide passageway for ion diffusion. [ABSTRACT FROM AUTHOR]

Abstract: The dual functional Al-doped ZnO (AZO) particles with photocatalysis and heat shielding capability were prepared by citric acid inducing sol-hydrothermal method. The effects of citric acid concentration on the microstructure, photocatalysis, and heat shielding property of AZO were investigated. The UV-Vis absorption spectra showed that the optical band gap energy of AZO were in the range of 2.93-2.79 eV and decreased with the increase of citric acid concentration in the precursor soliquid. The photocatalytic activity experiment results indicated that the as-prepared AZO products all exhibited higher photocatalytic efficiency than the pure TiO2-P25, and the photocatalytic efficiency increased with the increase of citric acid concentration. Particularly, the AZO sample synthesized with citric acid concentration 1.0 M exhibited the highest photocatalytic degradation rate for Rhodamine B under irradiation of ultraviolet light. Furthermore, the as-prepared AZO/polyvinyl alcohol (PVA) resin composite coatings on glass substrate exhibited better heat shielding property. The dual functional AZO particles with excellent photocatalytic activity and heat shielding property will have broad applications in the field of energy-saving and environmental purification.The dual functional Al-doped ZnO (AZO) particles with photocatalysis and heat shielding property were prepared by citric acid inducing sol-hydrothermal method. The effects of citric acid concentration on the microstructure, photocatalysis and heat shielding property of AZO were investigated. The dual functional AZO particles with excellent photocatalytic activity and heat shielding property will have broad applications in the field of energy-saving and environmental purification. [ABSTRACT FROM AUTHOR]

Monodisperse Yttrium-doped BaTiO3(YBT) nanoparticles with good crystallinity and uniform size distribution have been synthesised via a modified sol-hydrothermal method. The solubility of yttrium in BT was no more than 1 mol%. However, at higher Y3+content, excess Y3+were inclined to form Y(OH)3impurities, and after high temperature sintering, impurity YBa3Ti2O8.5can be detected in the ceramics. Further, the variation in the crystal volume indicated that Y3+preferred to substitute for Ti4+as an acceptor. FE-SEM images revealed that the grain size of the ceramics gradually decreased with the raising Y3+concentration. Notably, YBT ceramics with 3 mol% Y3+presented outstanding dielectric-temperature stability, benefitting from the diffuse ferroelectric–paraelectric phase transition and the existence of YBa3Ti2O8.5phases. Stable dielectric-temperature property and low dielectric loss of the YBT ceramics doping with 3 mol% Y3+in the range from 1 kHz to 1 MHz render it as a promising candidate material for high frequency application. [ABSTRACT FROM PUBLISHER]

Inorganic-framework molecularly imprinted TiO2/SiO2 nanocomposite (MIP-TiO2/SiO2) was successfully prepared by sol-hydrothermal method using 4-nitrophenol as template. The morphology, structure, optical property, zeta-potential and photocurrent of MIP-TiO2/SiO2 were characterized. The adsorption performance and photocatalytic selectivity were also studied. MIP-TiO2/SiO2 shows higher adsorption capacity and selectivity than the non-imprinted TiO2/SiO2 (NIP-TiO2/SiO2). Kinetics results show that the adsorption equilibrium of 4-nitrophenol on MIP-TiO2/SiO2 is established within 20 min, and the adsorption process obeys the pseudo-second-order model. Moreover, MIP-TiO2/SiO2 can completely degrade 4-nitrophenol within 30 min, while NIP-TiO2/SiO2 takes 110 min. It was found that the MIP-TiO2/SiO2 photocatalyst shows molecular recognition ability, leading to selective adsorption and molecular recognitive photocatalytic degradation of 4-nitrophenol. Furthermore, because of its inorganic framework, MIP-TiO2/SiO2 shows excellent reusability. [ABSTRACT FROM AUTHOR]

Abstract: TiO2 nanoparticles capped with sodium dodecylbenzenesulfonate (DBS) are synthesized by a sol–hydrothermal process using tetrabutyl titanate and DBS as raw materials. The effects of surface-capping DBS on the surface photovoltage spectroscopy (SPS), photoluminescence (PL) and photocatalytic performance of TiO2 nanoparticles are principally investigated together with their relationships. The results show that the surface of TiO2 nanoparticles can be well capped by DBS groups while the pH value and added DBS amount are controlled at 5.0 and 2% of TiO2 mass weight, respectively, and the linkage between DBS groups and TiO2 surfaces is mainly by means of quasi-sulphonate bond. The intensities of SPS and PL spectra of TiO2 obviously decrease after DBS-capping, while the activity can greatly increase during the photocatalytic degradation of Rhodamine B (RhB) solution, which are mainly attributed to the electron-withdrawing character of the DBS groups. Moreover, the enhancement of photocatalytic activity of DBS-capped TiO2 is also related to the increase in the capability for adsorbing RhB. [Copyright &y& Elsevier]

Nd-modified TiO 2 photocatalysts have been obtained via hydrothermal (HT) and sol-hydrothermal (SHT) methods. The as-prepared samples were characterized by X-ray diffraction (XRD), BET surface area measurements, scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), luminescence spectroscopy and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of the synthesized samples was evaluated by the degradation of phenol in aqueous solution under irradiation with UV-vis (λ > 350 nm) and vis (λ > 420 nm) light, as well as by the degradation of gaseous toluene under irradiation with vis (λ max = 415 nm) light. It was found that Nd-modified TiO 2 is an efficient photocatalyst for the degradation of phenol and toluene under visible light. XPS analysis revealed that the photocatalyst prepared via HT method contains a three-times higher amount of hydroxy groups at the surface layer and a two-times higher amount of surface defects than that obtained by the SHT method. The photocatalytic efficiency of phenol and toluene degradation under vis irradiation in the presence of 0.25% Nd-TiO 2 (HT) reached 0.62 and 3.36 μmol·dm -1 ·min -1 , respectively. Photocatalytic activity tests in the presence of Nd-TiO 2 and scavenger confirm that superoxide radicals were responsible for the visible light-induced degradation of the model pollutant in aqueous solution.

Inorganic-framework molecularly imprinted TiO2/SiO2 nanocomposite (MIP-TiO2/SiO2) was successfully prepared by sol-hydrothermal method using 4-nitrophenol as template. The morphology, structure, optical property, zeta-potential and photocurrent of MIP-TiO2/SiO2 were characterized. The adsorption performance and photocatalytic selectivity were also studied. MIP-TiO2/SiO2 shows higher adsorption capacity and selectivity than the non-imprinted TiO2/SiO2 (NIP-TiO2/SiO2). Kinetics results show that the adsorption equilibrium of 4-nitrophenol on MIP-TiO2/SiO2 is established within 20 min, and the adsorption process obeys the pseudo-second-order model. Moreover, MIP-TiO2/SiO2 can completely degrade 4-nitrophenol within 30 min, while NIP-TiO2/SiO2 takes 110 min. It was found that the MIP-TiO2/SiO2 photocatalyst shows molecular recognition ability, leading to selective adsorption and molecular recognitive photocatalytic degradation of 4-nitrophenol. Furthermore, because of its inorganic framework, MIP-TiO2/SiO2 shows excellent reusability., (Copyright © 2014 Elsevier B.V. All rights reserved.)