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Microwave-hydrothermal (M − H) synthesis of α-Sn(HPO4)2·H2O (α-SnP) was achieved here in as low as 5 min at 194 °C compared to several days by others previously. The use of microwaves in conjunction with the hydrothermal process enhanced the α-SnP synthesis reaction at least by two orders of magnitude. The super fast synthesis was apparently due to localized superheating where nucleation started and the reactions occurred very quickly in the localized superheated spots. The synthesized α-SnP was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). TEM revealed worm-like morphology at both low temperature and short duration of M − H treatment but at higher temperature platy morphology typical of layered phases resulted. The synthetic tin phosphate (α-SnP) phase is potentially useful as a cation exchanger, proton conductor and electrode material.

Here, we report a remarkable 15 A nanolayered tin phosphate, Sn(HPO4)2·3H2O (SnP–H+ or SnP), and its clay-like gel, which are multifunctional and are prepared using earth-abundant Sn and P chemicals by a facile, environmentally benign and potentially cost-effective process. This new energy material is discovered here as the best proton conductor among all the known layered phosphates with a very high proton conductivity of over 1 × 10−2 S cm−1 at 100 °C for potential use in PEM fuel cells. But it is also a very good capacitor material with fast Li-storage kinetics (charging time of 13 s).

Herein, we report a unique tin phosphate that is remarkably selective to (137)Cs(+) from extremly acidic solutions because of its special layered structure with an unusually large interlayer space. This acidic exchanger is superior to other existing materials in terms of its selectivity and capacity for (137)Cs(+) from acidic solutions.

Crystalline Co3O4 and Co(OH)(2) were synthesized using Co(NO3)(2) as a precursor by conventional-hydrothermal and microwave-hydrothermal routes, respectively. The Co3O4 phase showed cubic morphologies while the beta-Co(OH)(2) phase exhibited plate-like shapes. The electrochemical performances of Co3O4 and Co(OH)(2) phases were evaluated as electrode materials for lithium-ion battery anodes, cathodes and supercapacitors. Both Co3O4 and Co(OH)(2) phases showed pseudocapacitive performances in Li2SO4 and KOH electrolytes. The Co3O4 and Co(OH)(2) phases were found to be more promising as anodes than as cathodes in lithium-ion batteries. The Co(OH)(2) electrodes showed higher specific capacitances than those of Co3O4 materials. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

The LiMn2O4 electrode materials were synthesized by the conventional-hydrothermal and microwave-hydrothermal methods. The electrochemical performances of LiMn2O4 were studied as supercapacitors in LiNO3 electrolyte and lithium-ion battery cathodes. The microwave-hydrothermal method can synthesize LiMn2O4 electrode materials with reversible electrochemical reaction in a short reaction time and low reaction temperature than conventional-hydrothermal route. The capacitance of LiMn2O4 electrode increased with increasing crystallization time in conventional-hydrothermal route. The results showed that LiMn2O4 supercapacitors had similar discharge capacity and potential window (1.2 V) as that of ordinary lithium-ion battery cathodes. In LiNO3 aqueous electrolyte, the reaction kinetics of LiMn2O4 supercapacitors was very fast. Even, at current densities of 1 A/g and 5 A/g, aqueous electrolyte gave good capacity compared with that in organic electrolyte at a current density of 0.05 A/g.

Fe-based materials, fe2o3, fe3o4, and feooh, were synthesized by the microwave-hydrothermal process in the temperature range of 100-200 degrees c and under very short reaction times of 15 min to 2 h. under microwave-controlled hydrolysis and redox reactions, cube-like fe2o3 was crystallized using fecl3, fe3o4 particles were crystallized from fecl2 and feooh nanorods were crystallized using fecl3. the fe-based materials were fabricated to make anodes and cathodes of lithium-ion battery and supercapacitor electrode materials to study their potential electrochemical applications. the electrochemical results showed that feooh had better anode capacity as lithium-ion batteries than those of fe2o3 and fe3o4. the present results suggest that the microwave-hydrothermally synthesized fe-based materials are promising lithium-ion battery anode materials. (c) 2013 elsevier ltd and techna group s.r.l. all rights reserved.

Nanophase anatase was synthesized by a novel simplified one-pot method using Ti alkoxides and hydrogen peroxide under conventional- and microwave-hydrothermal conditions. The specific surface areas (SSAs) of anatase ranged from 147 to 298 m2/g under different hydrothermal conditions but higher SSAs were obtained under microwave-hydrothermal conditions. The novel method developed here results in nanophase anatase with superior DeNOx properties.

We report a coupled microwave–hydrothermal process to crystallize polymorphs of MnO2 such as α-, β-, and γ-phase samples with plate-, rod-, and wirelike shapes, by a controllable redox reaction in MnCl2–KMnO4 aqueous solution system. MnCl2–KMnO4 redox reaction system was for the first time applied to MnO2 samples under the coupled microwave–hydrothermal conditions, which shows clear advantages such as shorter reaction time, well-crystallized polymorphic MnO2, and good electrochemical performances as electrode materials for lithium ion batteries. For comparison, we also did separate reactions with hydrothermal only and microwave only in our designed MnCl2–KMnO4 aqueous system. The present results indicate that MnCl2–KMnO4 reaction system can selectively lead to α-, β-, and γ-phase MnO2, and the as-crystallized MnO2 samples can show interesting electrochemical performances for both lithium-ion batteries and supercapacitors. Electrochemical measurements show that the as-crystallized MnO2 supercapacitors have...

Apparently C-doped and undoped or pure nanoparticles of anatase were synthesized using a microwave hydrothermal process in the temperature range of 140–180 °C for 1 h from several Ti precursors, such as Ti ethoxide, Ti isopropoxide and Ti oxysulfate. Nanoparticles of anatase samples were characterized by powder X-ray diffraction, transmission electron microscopy (TEM) and photocatalytic activity measurements. Results showed that nanoparticles in the size range of 4–17 nm of anatase were obtained in all cases with surface areas in the range of 151–267 m 2 /g. The photocatalytic activity of the prepared titanias was measured using methylene blue (MB) and NO x molecules. Because MB has very strong adsorption on the samples, photocatalytic degradation under either solar light or black light irradiation was found to be very limited. However, the DeNO x abilities of carbon-doped titanias were higher than those of Degussa P25 commercial titania sample and undoped or pure titanias especially under irradiation by long wavelength or visible light (>500 nm).

Parameters such as temperature, time and presence or absence of microwaves affected the particle size and magnetic properties of synthetic magnetite. The presence of microwaves during crystallization significantly increased the particle size of magnetite in a short time with improved magnetic properties. Magnetite samples were characterized by X-ray diffraction, transmission electron microscopy (TEM) and saturation magnetization measurements. The TEM crystal sizes varied from about 40 to 50 nm at room temperature to greater than 50 nm with wider crystal size distribution at higher temperatures. The saturation magnetization values of synthetic magnetites ranged from 57.4 to 89.0 emu/g.