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Microwave-induced nitrogen-doped titanate nanotubes (NTNTs) were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), Zeta potential analysis, specific surface area (SBET), and UV-Visible spectroscopy. TEM results indicate that NTNTs retain a tubular structure with a crystalline multiwall and have a length of several hundred nanometers after nitrogen doping. XRD findings demonstrate that the crystalline structure of NTNTs was dominated by anatase, which is favored for photocatalytic application. The Ti-O-N linkage observed in the XPS N 1s spectrum is mainly responsible for narrowing the band gap and eventually enhancing the visible light photoactivity. FT-IR results demonstrated the existence of H₃O⁺, which could be excited by photo-generated holes to form hydroxyl radicals and degrade environmental pollutants. After sintering at 350°C, the UV-Vis absorbance edges of NTNTs significantly shift to the visible-light region, which indicates N atom doping into the nanotubes. Photocatalytic degradation of Rhodamine B (RhB) via NTNTs show good efficiency, with pseudo first-order kinetic model rate constants of 3.7 × 10⁻³, 2.4 × 10⁻³ and 8.0 × 10⁻⁴ sec⁻¹ at pH3, 7, and 11, respectively., (Copyright © 2014. Published by Elsevier B.V.) more...

Synthesis of nitrogen-doped carbon dots (N-CDs) using urea and ascorbic acid as carbon sources is addressed in this study using a microwave-assisted hydrothermal technique. The samples were characterized by ultraviolet, photoluminescence (PL) and transmission electron microscopy analyses, which confirmed the formation of CDs. Besides PL properties, the peroxidase-like catalytic activity of the CDs and N-CDs was also compared. Interestingly, the N-CDs exhibit higher peroxidase-like catalytic activity than pure CDs and can be used to detect H2O2. Additionally, we synthesized several N-CD ratios and evaluated their peroxidase-like catalytic activity. [ABSTRACT FROM AUTHOR] more...

As a typical binary transition metal oxide, ZnFe2O4 has attracted considerable attention for supercapacitor electrodes due to its high theoretical specific capacitance. However, the reported synthesis processes of ZnFe2O4 are complicated and ZnFe2O4 nanoparticles are easily agglomerated, leading to poor cycle life and unfavorable capacity. Herein, a facile microwave hydrothermal process was used to prepare ZnFe2O4/reduced graphene oxide (rGO) nanocomposites in this work. The influence of rGO content on the morphology, structure, and electrochemical performance of ZnFe2O4/rGO nanocomposites was systematically investigated. Due to the uniform distribution of ZnFe2O4 nanoparticles on the rGO surface and the high specific surface area and rich pore structures, the as-prepared ZnFe2O4/rGO electrode with 44.3 wt.% rGO content exhibits a high specific capacitance of 628 F g−1 and long cycle life of 89% retention over 2500 cycles at 1 A g−1. This work provides a new process for synthesizing binary transition metal oxide and developing a new strategy for realizing high-performance composites for supercapacitor electrodes. [ABSTRACT FROM AUTHOR] more...

In this work, a novel Co/CoAl 2 O 4 /sepiolite nanocomposite was synthesized by reducing the CoAl 2 O 4 /sepiolite nanocomposite prepared via a microwave hydrothermal method. The effects of the content of sepiolite, types of the organic matters used, and their dosage on the microstructure of the CoAl 2 O 4 /sepiolite nanocomposite were investigated and the optimal conditions for fabricating the CoAl 2 O 4 /sepiolite nanocomposite were identified. Subsequently, the influence of the reduction temperature on the microstructure of the Co/CoAl 2 O 4 /sepiolite nanocomposite was studied. According to the various surface characterizations, the sample synthesized under the optimal conditions (i.e., with 10 vol% triethanolamine and 10 wt% sepiolite followed by the reduction at 650 °C for 3 h) showed spherical CoAl 2 O 4 evenly dispersed on sepiolite nanofibers along with fine cobalt nanoparticles embedded on the surface of CoAl 2 O 4. As a model reaction, Fischer-Tropsch synthesis was examined with the as-synthesized materials. The optimal sample has demonstrated a higher selectivity for C 5+ (high-carbon hydrocarbons) and lower selectivity for CO 2 , CH 4 , and C 2 –C 4 compared with the control sample. This work is believed to provide an effective strategy for low-cost batch fabrication of highly efficient supported cobalt-based catalysts with a novel transition layer where fine Co nanoparticles can be anchored with good dispersion. [ABSTRACT FROM AUTHOR] more...

Microwave hydrothermal treatment is a promising technology for the environmentally friendly disposal and resource utilization of dead pigs. However, the hydrothermal transformation mechanism of animal-based biomass is unclear, impeding the regulated conversion of target products. To address this, bovine serum albumin, glycerol-oleic acid, and glucose were selected as model compounds for protein (P), lipid (L), and carbohydrate (C), respectively. In this paper, the product distribution and related properties of single, binary, and ternary model compounds at different microwave hydrothermal temperatures (120–240 °C) were investigated, and the essential reaction pathway of the dead pig model compounds during microwave hydrothermal treatment was proposed. The results showed that lipids dominated the formation of bio-oil. L&C and L&P showed a slight synergistic effect on bio-oil yield at 240 ℃, while exhibited antagonistic effects at other temperatures. L&P&C showed antagonistic effects on bio-oil yield at all temperatures. The participation of glucose was more conducive to the formation of carbonized solid products. The model compounds of dead pigs underwent a series of reactions such as dehydration, decarboxylation, deamination and condensation during microwave hydrothermal treatment. To a certain extent, lipids promoted the Maillard reaction of protein and carbohydrate, while glucose promoted the esterification reaction of fatty acids. [Display omitted] • The microwave hydrothermal was selected to transform typical animal-based biomass. • The model compounds were used for learning the conversion mechanism of dead pig. • The interactions of model compounds for product distribution were investigated. • Exploration of reaction pathways of dead pig during microwave hydrothermal process. [ABSTRACT FROM AUTHOR] more...

In this work, a novel microwave hydrothermal method is developed to prepare hybrid 1T@2H−MoS2 nanospheres, with the 1T and 2H phases confirmed by high‐resolution transmission electron microscopy (HRTEM), X‐ray photoelectron spectroscopy (XPS) and the stability of the hybrid phase verified by Raman spectroscopy. The efficiencies of methyl orange (MO) degradation and photo‐reduction of Cr(VI) by hybrid 1T@2H−MoS2 are much higher than those by 2H−MoS2, which should be attributed to the synergistic effect of the coexistent 1T and 2H phases. In addition, the hybrid sample prepared by microwave method possesses superior photocatalytic performance than that by conventional hydrothermal method, due to the higher 1T phase concentration and different crystallinity. Free‐radical capture experiments show that.O2− dominates the photocatalytic degradation process with 1T phase producing more electrons. The introduction of 1T−MoS2 into 2H−MoS2 shows great potential for photocatalytic degradation, while microwave treatment could be an effective method to prepare the hybrid phase MoS2. [ABSTRACT FROM AUTHOR] more...

A blue and bright CoAl 2 O 4 nanocomposite is fabricated by the microwave hydrothermal synthesis at the optimum conditions (pH = 13, 240 °C, 4 h, 15:1 of the metal salt to sepiolite). More interestingly, a significant improvement in the distribution of the supported CoAl 2 O 4 nanoparticles can be realized through the strategy of microwave hydrothermal coupled with surface modification by surfactants, which results in significantly improved suspension performance. The synthesis strategy is believed to provide a guide for the fabrication of supported nanocomposites with a uniform particle size for diverse applications such as heterogeneous catalytic reactions, ceramic materials, water-based coatings, and so on. [ABSTRACT FROM AUTHOR] more...

Abstract In order to improve the electrochemical performance of supercapacitors, a novel 3D flower-like NiMnO 3 nanoballs electrode material were prepared by microwave-assisted hydrothermal methods at different deposition temperature. The crystal phase, chemical valence states and function groups of the as-prepared material were analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Bruker transform infrared spectra (FT-IR). The Field-emission scanning electron microscopy (SEM), transmission electron microscope (TEM) and Brunauer-Emmett-Teller (BET) were reveals sample's morphology and the surface area. Its electrochemical performance was evaluated by traditional three-electrode system in 6 mol/L KOH solution. The results indicated that the morphology of NiMnO 3 electrode material changed from nanobulks to flower-like nanoballs with temperature increasing. The optimal temperature was 160 °C. At this point, the specific capacitance reached 345.8 F g−1 at 1 A g−1. The specific capacitance retention maintained about 92% after 1000 cycles at 3 A g−1. Owing to flower-like structure, which not only increased the surface area but also added the electrolyte ion transfer channels, that contributed to increasing the electrochemical properties. The good cycle stability and the high specific capacity, lead to NiMnO 3 become a promising candidate for the next generation supercapacitor electrode material. Highlights • We had first successfully synthesis NiMnO 3 by microwave-assisted hydrothermal strategy. • The material of NiMnO 3 has novel flower-like nanoballs morphology. • The NiMnO 3 electrode material has long cycle life (about 92% after 1000 charge-discharge at 3 A g−1). [ABSTRACT FROM AUTHOR] more...

Cu doped α-NiMoO 4 photocatalyst has been synthesized by microwave hydrothermal method. The existence of Cu 2+ ions at lattice position of α-NiMoO 4 was observed on the basis of XRD, HRTEM, SAED, and EDS analysis. The negative zeta potential values indicate the stability of samples. Solar light driven photocatalytic degradation of Methylene blue (MB) dye in water was used to evaluate the photocatalytic performance of Cu doped α-NiMoO 4 photocatalyst. The results revealed that there is an optimum Cu (4 mol%) doping level leads to highly enhanced photocatalytic activity of Cu-α-NiMoO 4 , as compared to α-NiMoO 4 host. The experiment also suggested that active species (OH , O 2 − and h + ) play a crucial role in the scavenging system. The reduced energy band gap, oxygen vacancy, high BET surface area, and efficient separation of photogenerated electron/hole are responsible for enhancement of photocatalytic performance. MB photodegradation intermediates were identified by high resolution-quadruple time of flight electrospray ionization mass spectrometry (HR-QTOF ESI/MS) in positive ion mode and degradation pathway was proposed. Antibacterial performance was analyzed against Gram-positive (methicillin resistant Staphylococcus aureus and Bacillus Subtilis ) and Gram-negative bacteria ( Pseudomonas aeruginosa ) via well-diffusion method. The formation of larger inhibition zone by small quantity of photocatalyst powder proved the excellent antibacterial performance. The inactivation of microorganism were found in following order: B . Subtilis ˃ S . aureus ˃ P . aeruginosa . The result of our study suggested that copper doped α-NiMoO 4 photocatalyst is suitable for degradation of organic contaminates as well as effective for growth inhibition of multidrug-resistant microorganisms. [ABSTRACT FROM AUTHOR] more...

A one-step microwave hydrothermal method is proposed here for the harmless treatment and resource recycling of water-washed municipal solid waste incineration fly ash (WMSWI-FA). Dioxins and heavy metals in WMSWI-FA can be detoxified, tobermorite can be synthesized by adjusting the parameters of NaOH dosage, reaction temperature and time. We conclude that NaOH is essential to synthesize tobermorite from WMSWI-FA, and higher temperatures and longer times are beneficial for degrading dioxins. However, excessive NaOH has a negative effect on the degradation of dioxins. Experiments showed that adding 20 wt% NaOH to WMSWI-FA and reacting at 260 °C for 3 h, the tobermorite was successfully synthesized, the residual dioxins (42.80 ng-TEQ/kg) and the leaching concentrations of heavy metals were lower than the limited value of the HJ 1134–2020 standard. The hydrothermal treated WMSWI-FA contains tobermorite, which supports it to be recycled as construction material and adsorbent. The one-step microwave hydrothermal treatment demonstrates favorable industrialization prospects, as it performs well in harmless treatment and resource utilization of WMSWI-FA. [Display omitted] • One-step microwave hydrothermal method is a promising treatment for WMSWI-FA. • Dioxins can be detoxified to 42.80 ng-TEQ/kg to meet the requirement for recycling. • Above 91% of heavy metals can be stabilized in the hydrothermal product. • Porous tobermorite was synthesized in hydrothermal treatment of WMSWI-FA. • Quartz sand (Ca/Si=1.1), 20 wt% NaOH and reaction at 260 °C for 3 h are suggested. [ABSTRACT FROM AUTHOR] more...

The Yb 3+ -Er 3+ -Y 3+ tri-doped cubic ZrO 2 (brief as YSZ:Yb, Er) nanophosphors with different Yb 3+ (Er 3+ ) doping concentrations have been prepared by microwave hydrothermal method followed by further calcining treatment. X-ray diffraction (XRD), transmission electron microscope (TEM), and photoluminescence spectra were used to characterize the properties of YSZ:Yb, Er nanophosphors. Under the 980 nm excitation, the sample gives a set of upconversion light: very strong red emissions near 655 and 679 nm ( 4 F 9 / 2 → 4 I 15/2 ), very weak green (525 nm 2 H 11/2 → 4 I 15/2 , 544 nm and 557 nm 4 S 3/2 → 4 I 15/2 ). Moreover, the sample gives near-infrared downconversion emission (1530 nm 4 I 13/2 → 4 I 15/2 ). Concentration dependent studies revealed that the optimal composition was realized for the 15 at% Yb 3+ and 1 at% Er 3+ -doping concentration with a strong pure red emission. All the results indicate that YSZ:Yb, Er nanophosphors could be a promising biological labeling materials. [ABSTRACT FROM AUTHOR] more...

We report for the first time a rapid preparation of Zn 1−2 x Co x Ni x O nanoparticles via a versatile and environmentally friendly route, microwave-assisted hydrothermal (MAH) method. The Co, Ni co-doped ZnO nanoparticles present an effect on photoluminescence and electrochemical properties, exhibiting excellent electrocatalytic performance compared to undoped ZnO sample. Photoluminescence spectroscopy measurements indicated the reduction of the green–orange–red visible emission region after adding Co and Ni ions, revealing the formation of alternative pathways for the generated recombination. The presence of these metallic ions into ZnO creates different defects, contributing to a local structural disorder, as revealed by Raman spectra. Electrochemical experiments revealed that the electrocatalytic oxidation of dopamine on ZnO attached to multi-walled carbon nanotubes improved significantly in the Co, Ni co-doped ZnO samples when compared to pure ZnO. [ABSTRACT FROM AUTHOR] more...

A facile microwave hydrothermal route is employed to synthesized NH 4 V 3 O 8 ultralong nanobelts without any surfactant. The prepared NH 4 V 3 O 8 nanobelts have an average width of 40–60 nm and a length of tens of micrometers growing along [0 0 1] direction. When used as cathode material for lithium ion battery, the NH 4 V 3 O 8 nanobelts show high discharge capacity (337 mAh g −1 at 15 mA g −1 ), nice cycling stability (98% after 100 cycles) and good rate capability (279, 248, 220, and 192 mAh g −1 at 60, 120, 240 and 300 mA g −1 , respectively). The good electrochemical property of the NH 4 V 3 O 8 is attributed to its unique ultralong nanobelt structure with good structural stability. [ABSTRACT FROM AUTHOR] more...

CuO nanoparticles with different morphologies were synthesized by chemical precipitation and subsequently modified by microwave hydrothermal processing. The nanoparticles were precipitated by the introduction of a strong base to an aqueous solution of copper cations in the presence/absence of the polyethylene glycol and urea additives. The modification of the nanoparticles was subsequently carried out by a microwave hydrothermal treatment of suspensions of the precipitates, precipitated with and without the additives. X-ray powder diffraction analysis indicated that the crystallinity and crystallite size of the CuO nanoparticles increased after the microwave hydrothermal modification. Microscopy observations revealed the morphology changes induced by microwave hydrothermal processing. The thermal decomposition of ammonium perchlorate and the detection of volatile gases were performed to evaluate the catalytic and gas sensing properties of the synthesized CuO nanoparticles. [ABSTRACT FROM AUTHOR] more...

A microwave hydrothermal method was developed to deposit WO 3 on Al 2 O 3 for rapidly preparing W/Al 2 O 3 hydrodesulfurization (HDS) catalysts with both high tungsten dispersion and weak tungsten–alumina interaction. The catalysts were characterized by XRD, XPS, N 2 adsorption, H 2 -TPR, NH 3 -TPD and HRTEM; their activity was tested by HDS of dibenzothiophene. Compared to the previous hydrothermal deposition method, the microwave hydrothermal method can further increase the dispersion of tungsten and attain the similar weak tungsten–alumina interaction, leading to the shorter and similar stacked WS 2 and hence higher HDS activity, whereas the hydrothermal period is dramatically reduced from 12 h to 15 min. Moreover, this method can highly disperse more tungsten on alumina than the hydrothermal deposition and impregnation methods. It is attributed to the rapid nucleation and inhibited growth of WO 3 , and the enhanced mobility induced by microwave hydrothermal conditions. The significance of this method lies in its simplicity and efficiency for preparing tungsten-based catalysts with superior HDS activity. [ABSTRACT FROM AUTHOR] more...

Pure orthorhombic phase BiWO powders were synthesized by a microwave hydrothermal method in the absence of surfactants and templates, using Bi(NO)·5HO and NaWO·2HO as raw materials. Photocatalytic properties of the samples prepared at different reaction temperatures were also studied with Rhodamine B (RhB) solution as the target catabolite under visible light. The results indicate that flower-like BiWO powders can be obtained by controlling the microwave reaction temperatures in the absence of any additives. The growth of flower-like BiWO powders is a multistage layer assembly process, in which the flower-like BiWO self-assembling with the uniform size about 2 μm is synthesized at 180 °C. At the same time, the photocatalytic reaction rate constant ( k) gets up to 0.04167/min and the degradation rate of RhB solution is more than 96 % after being irradiated under visible light for 70 min. [ABSTRACT FROM AUTHOR] more...

Li-rich layer-structure xLi2MnO3·(1 − x)LiNi1/3Co1/3Mn1/3O2 (x = 0.2, 0.4, 0.6, 0.8) cathode materials have been synthesized by co-precipitation and microwave hydrothermal (MH) method in a short time (∼60 min). The crystal structure is characterized by X-ray diffraction (XRD) patterns, and refined by two sets of diffraction data (R-3m and C2/m). The morphology is characterized by scanning and high-resolution transmission electron microscope (SEM and HRTEM) which shows the average particle size (50–100 nm). The charge/discharge results indicate xLi2MnO3·(1 − x)LiNi1/3Co1/3Mn1/3O2 (x = 0.4) synthesized at 180 °C for 60 min has the best discharge capacity and cyclic performance. Within the cut-off voltage between 2.5 and 4.8 V, the initial discharge capacity is 325 mA h g−1 at 0.1 C rate; and after 50 cycles the discharge capacity remains 234.5 mA h g−1. The xLi2MnO3·(1 − x)LiNi1/3Co1/3Mn1/3O2 prepared by facile and rapid microwave-assisted hydrothermal (MH) is a promising preparation method in cathode material for lithium ion batteries. [ABSTRACT FROM AUTHOR] more...

Abstract: In this work, CuO nanoparticles of varying shape (tadpole-shaped, spindly, leaf/sphere-like and fusiform) have been prepared by a facile microwave-assisted hydrothermal (MH) method. The products were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy FTIR and transmission electron microscopy (TEM). XRD and TEM results revealed pure phase monoclinic CuO nanoparticles with uniform shapes and sizes. FTIR and UV–vis measurements of these nanoparticles with varying shape showed a highly shape-dependent nature. The gas sensing performance of the obtained nanoparticles was analyzed by detection of target gases, including methanol, ethanol and acetone at 220°C. The tadpole-shaped CuO nanoparticles displayed the best response of ∼5 toward 1000ppm methanol, ∼7 toward 1000ppm ethanol, and ∼8 toward 800ppm acetone, respectively. All these CuO-based sensors exhibited a relatively higher response to acetone when compared to their response toward methanol and ethanol. The enhanced sensing performance of the tadpole-shaped CuO sensor may be attributed to their unique shape and small size, which is more favorable in rapid and efficient diffusion of organic vapors than the other shaped CuO nanoparticles. [Copyright &y& Elsevier] more...

Abstract: Well-crystallized Mn3O4-anchored reduced graphene oxide (rGO) nanocomposites have been successfully synthesized via a facile, effective, energy-saving, and scalable microwave hydrothermal technique for potential application as supercapacitor material. Integrating these nanostructures resulted in a strong synergistic effect between the two materials, consequently leading to a hybrid composite with higher specific capacitance compared to the bare Mn3O4 nanoparticles. The results from different sorts of characterization indicate that the Mn3O4 particles were deposited and anchored on graphene sheets. The capacitance value of the rGO(31.6%)–Mn3O4 nanocomposite reached 153F/g, much higher than that of the bare Mn3O4 (87F/g) at a scan rate of 5mV/s in the potential range from −0.1V to 0.8V. More importantly, a 200% increase in capacitance was observed for the nanocomposite with cycling at 10mV/s due to electrochemical activation and the oxidization of Mn(II,III) to Mn(IV) during cycling, as verified by X-ray photoelectron spectroscopy. There is no observable capacitance fading up to 1000 cycles. The facile synthesis method and good electrochemical properties indicate that the nanocomposite could be an electrode candidate for supercapacitors. [Copyright &y& Elsevier] more...

Abstract: Bi2Fe4O9 crystals were successfully prepared via a rapid and facile microwave hydrothermal (MH) process. The influences of the various preparation parameters (including the NaOH concentration, and holding time) on the phase formation and morphology development were investigated in detail. XRD results showed that Bi2Fe4O9 crystal was formed indirectly with an intermediate phase of Bi25FeO40 in the MH process, whose further formation mechanism was discussed based on the morphology development. Moreover, the photocatalytic efficiencies of Bi2Fe4O9 products obtained at the different holding times were evaluated by the degradation of methyl orange under visible light irradiation. It was found that the photocatalytic activities were greatly dependent on the holding time. [Copyright &y& Elsevier] more...

Abstract: One-dimensional (1D) CuS microstructures of assembled chains and rods have been prepared using a facile polyvinylpyrrolidone (PVP) assisted microwave hydrothermal (MH) method. The crystallites were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and UV–vis optical absorption spectroscopy. The crystal growth and morphology evolution process have been investigated through time-dependent experiments, and the assembling of sphere into chain-like structure and the further transformation into rod-like morphology are observed. A possible formation mechanism of the as-obtained 1D structure was proposed after the investigation of the effects of the concentration of PVP and the solvent on the final products in detail. The UV–vis spectra of the spherical and rod-like CuS crystallites show a strong absorption in the visible spectrum between 500nm and 800nm, while the rod-like structure exhibits a distinct red shift compared to the spheres. [Copyright &y& Elsevier] more...

Abstract: Boron is an essential nutrient for animals and plants, but it can be harmful in excessive levels. In this study, three types of crushed shells (oyster, hard clam and freshwater clam) were pretreated and then reused as mineralizers to remove and recover the boron from concentrated wastewater by using the microwave hydrothermal method. Chemical and physical properties of raw and pretreated crushed shells were determined and compared using SEM, XRD, BET and WD-XRF. Effects of pretreatment method (heated or pyrolysis), particle sizes, initial boron concentrations, reaction times and shells dosages on boron recovery were investigated. The oyster shells pretreated by heat performed better than heated hard clam and freshwater clam shells, and the boron recovery efficiency reached around 95% within 10min of reaction time. The experimental results indicate that the pretreated oyster shell is an effective mineralizer for removal and recovery of boron from concentrated wastewater. [Copyright &y& Elsevier] more...

Abstract: Modern accelerator design practice includes the use of high-quality ferrites for circulator applications with ever-increasing requirements on power handling ability. Modeling studies of new designs are of increasing economic importance, but are frequently hindered by lack of measured values of the ceramic loss factors. We have developed a nanocrystalline ferrite material with composition Ni0.94Co0.03Mn0.04Cu0.03Fe1.96O4. Nanocrystalline NiCoMnCu ferrite powders were synthesized using a microwave-hydrothermal method at 160°C for 40min. The ferrite formation conditions, such as pH, temperature and time, were optimized. The phase of the samples was identified by X-ray diffraction and was characterized by Fourier transformation infrared spectroscopy. The size of the nanocrystalline ferrite of as-synthesized powders was 10nm. The powder was densified at different temperatures using a microwave sintering method. The complex permittivity and permeability of the sintered samples were measured over a frequency range from 10kHz to 1.8GHz at room temperature. The applicability of the samples for circulators was tested via the measurement of the ferromagnetic resonance linewidth and the results are presented. [Copyright &y& Elsevier] more...

Abstract: Boron compounds are widely-used raw materials in industries. However, elevated boron concentrations in aqueous systems may be harmful to human and plants. In this study, calcium hydroxide (Ca(OH)2) alone and Ca(OH)2 with phosphoric acid (H3PO4) addition (P-addition) were used to remove and recover boron from wastewater using hydrothermal methods. A microwave (MW) hydrothermal method was used and compared with the conventional heating (CH) method in batch experiments. Physicochemical properties of the precipitates obtained from both methods were analysed by XRD, SEM with EDX and BET. For the case of Ca(OH)2 alone and the MW method, experimental results showed that boron recovery efficiency reached 90% within 10min, and crystals of Ca2B2O5·H2O were found in the precipitates as indicated by the XRD analysis. For the case of P-addition and the MW method, boron recovery efficiency reached 99% within 10min, and calcium phosphate species (CaHPO4·H2O, CaHPO4 and Ca10(PO4)6(OH)2) were formed. The experimental results of this study indicate that the required reaction time of the MW method was much less than that of the CH method, and the MW method is an effective and efficient method for boron removal and recovery from concentrated wastewater. [Copyright &y& Elsevier] more...

Abstract: AgIn5S8 powders were successfully synthesized by a microwave hydrothermal method for the first time. This method is a mild and highly efficient route involves no templates, catalysts, or surfactants. Therefore, it is very promising for the low-cost and large-scale industrial production. The samples were characterized by X-ray diffraction, UV–vis spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. The photocatalytic activity of AgIn5S8 nanoparticles was investigated through the degradation of methyl orange under visible light irradiation. Compared with TiO2−x N x , AgIn5S8 has exhibited a superior activity under the same condition. A liquid chromatogram-mass spectrometer was used to separate and identify the dye and degradation products generated during the reaction. According to the experiment results, a possible mechanism for the degradation of organic pollutant over AgIn5S8 was proposed. [ABSTRACT FROM AUTHOR] more...

Abstract: In this study, (Y,Gd)2O3 and (Y,Gd)2O3:Eu flowerlike microstructures were prepared through two steps: well-organized 3-dimensional (3D) flowerlike precursors were first synthesized by a facile urea-based microwave hydrothermal method, then followed by heat treatment. The morphology of the 3D flowerlike precursors could be modulated by adjusting the synthetic conditions including concentration of the starting material, reaction time and temperature. Higher the concentration of Y/Gd ions or reaction temperature, earlier the 3D flowerlike precursors were obtained. The samples were characterized by various means. The flowers were found to derive from colloidal spheres, which experienced a dissolution/crystalline, attachment and self-assembly process. Room temperature photoluminescence spectrum of 3D flowerlike (Y,Gd)2O3:Eu showed enhanced emission property than the spheres. [Copyright &y& Elsevier] more...

Abstract: The influence of the preparation conditions in the microwave-hydrothermal process in the morphology and electrochemical properties of LiNi1/3Co1/3Mn1/3O2 powders was investigated in this study. When the microwave radiation temperature was raised from 100°C to 180°C, the particles exhibited a less-agglomerated morphology and reduced particle sizes. Increasing the microwave radiation temperatures for preparing the precursors increased the LiNi1/3Co1/3Mn1/3O2 powder surface area and also improved the electrochemical performance. When the microwave radiation temperature was increased to 180°C, the discharge capacity of the prepared powders was approximately 170mAh/g and the retention was 98.5% after 10 cycles. The obtained powders exhibited a high lithium-ion diffusion coefficient and good rate capability. These results demonstrate that the microwave-hydrothermal method is a potential process for preparing LiNi1/3Co1/3Mn1/3O2 powders with large specific capacity, good cyclic stability and excellent rate capability. [Copyright &y& Elsevier] more...

We present in this paper the synthesis of rutile TiO2 nanorods using an efficient microwave hydrothermal method. The product was characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy, and the results indicated the growth of high quality rutile nanorods along the c-axis of rutile TiO2 and the radial aggregation of them into spherical secondary nanoparticles. [ABSTRACT FROM AUTHOR] more...

[Display omitted] • Spherical Al 2 O 3 precursors were rapidly synthesized at low temperature by M-H. • Effects of process factors in M-H on the properties of particles were studied. • The mechanism of M-H synthesis of spherical Al 2 O 3 was investigated. Spherical α-Al 2 O 3 particles with the size of 1–2 μm were obtained by microwave hydrothermal(M-H) method and subsequent microwave calcination. In the synthesis, Al 2 (SO 4) 3 ·18H 2 O was used as the aluminum sources, and CH 4 N 2 O was used as the precipitant. The effects of M-H temperature, heating preservation time and pressure in the reactor on the morphology, phase composition, particle size and surface area of the particles were studied. The results show that amorphous precursors with high sphericity and good dispersion can be rapidly (30 min) produced by M-H method at low temperature (100 °C). Increasing the temperature or extending the holding time will destroy the spherical morphology of the precursor, while transforming its phase from amorphous to γ-AlOOH. Pressure in the reactor does not change the phase composition of the precursor, but affects its dispersion and homogeneity. The precursor retains its spherical morphology after microwave calcination at 1100 °C for 90 min. The resulting powders were hot pressed and sintered at 1650 °C for 30 min to obtain a high-performance ceramic plate with a thermal conductivity of 27.1 W/(m·K) and a Vickers hardness of 21.4 GPa. [ABSTRACT FROM AUTHOR] more...

• g-C 3 N 4 nanosheets are successfully prepared by microwave hydrothermal assisted method. • This method is facile, efficient and green. • The g-C 3 N 4 nanosheets perform excellent H 2 evolution activity and stability. • The generality of the microwave hydrothermal method was investigated by the g-C 3 N 4 originated from different precursors. Herein, a microwave hydrothermal method was developed for constructing g-C 3 N 4 nanosheets. The specific surface area of the photocatalyst using this method was larger than the bulk carbon nitride. In addition, this method yields g-C 3 N 4 with a lower electron-hole recombination rate and faster interface charge transport. Particularly, the conduction band shifts to a more negative position, leading to better reducibility. As expected, the g-C 3 N 4 nanosheets had excellent activity in hydrogen evolution (over 10 times that of the bulk carbon nitride). Additionally, the photocatalyst prepared using this method had good stability in the hydrogen evolution reaction. This work proposes a new, universal, facile and green technique route for preparing g-C 3 N 4 nanosheets. [ABSTRACT FROM AUTHOR] more...

TiO 2 nanostructures have been prepared via microwave hydrothermal process using different NaOH concentrations. The physicochemical properties of the products were systematically investigated by using UV–vis Diffuse Reflectance Spectra, X-ray Photoelectron Spectra, Photoluminescence Spectra, Raman, N 2 adsorption-desorption, and Transmission Electron Microscope analysis. The results indicated a close correlation between the NaOH concentration and different types of nanostructured titania products obtained from the microwave-assisted hydrothermal process. At low NaOH concentrations (4 M and 6 M), the precursor TiO 2 nanoparticles partially converted into a mixture of one dimensional (1D) nanostructures (e.g., nanorods or nanowires) and 2D nanostructures such as nanosheets. As the NaOH concentration is increased to 8 M and 10 M, the obtained TiO 2 products contain nanosheet and nanotube-like structures, respectively, with a significantly larger specific surface area. The photocatalytic performance of the synthesized TiO 2 products, prepared under different NaOH concentrations, were evaluated through the toxic NO x gas removal efficiencies. The nanostructured TiO 2 samples prepared at a higher NaOH concentration have shown improved de-NO x efficiencies than the TiO 2 –P25 precursor. • One dimensional TiO 2 nanostructures were successfully synthesized via microwave hydrothermal method. • Effects of NaOH concentration on the physicochemical properties of as-prepared TiO 2 were analyzed. • Heterojunctions among TiO 2 nanoparticles, nanosheets or nanotubes reduced the recombination rate of charge carriers. • As-prepared TiO 2 products showed a significant improvement in de-NO x conversion in comparison with TiO 2 -P25. [ABSTRACT FROM AUTHOR] more...

Abstract: Monodisperse crystalline WO3·2H2O (H2WO4·H2O) nanospheres have been prepared by l (+) tartaric acid-assisted microwave hydrothermal (MH) process for the first time. The X-ray powder diffraction (XRD) pattern indicated that the product was in good agreement with the standard JCPDS data for WO3·2H2O. The particle sizes and shapes have been measured by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques. The effects of the mass ratios of l (+) tartaric acid to Na2WO4·2H2O on the morphology of WO3·2H2O have been investigated. Finally, The formation mechanism for l (+) tartaric acid-assisted MH synthesis of the WO3·2H2O nanospheres was also discussed in detail. [Copyright &y& Elsevier] more...

This study was conducted to explore the effects of microwave and conventional hydrothermal (MH and CH) treatment on the conversion of chicken carcasses into bio-oil. The differences between MH and CH treatment in terms of bio-oil yields and properties under different reaction temperatures (120–240 °C) were investigated. The bio-oil yield under CH treatment was higher at low temperatures (120–160 °C), whereas that under MH treatment was higher at high temperatures (200–240 °C). The maximum bio-oil yield of 59.41% was obtained by MH treatment at 240 °C. The higher heating values of all bio-oils (34.98–37.22 MJ·kg−1) were significantly higher than that of chicken feedstock (26.46 MJ·kg−1). The bio-oil contained a complex mixture of components that were mainly fatty acids. The bio-oil obtained by MH treatment at 240 °C showed the best flammability and comprehensive combustion performance. The gaseous products in the entire combustion process of bio-oil were mainly CO 2 and (C–H)-containing volatiles; additionally, compounds containing H 2 O, CO, SO 2 , HCN, C O, and C–O were detected. Compared to bio-oil obtained by CH treatment, that obtained by MH treatment showed a higher calorific value, lower relative content of nitrogen, better flammability, and improved comprehensive combustion performance under the same hydrothermal reaction conditions. • The bio-oils have higher HHVs in the range of 34.98–37.22 MJ kg−1. • The combustion processes of bio-oil and chicken carcasses were studied. • The evolution of gaseous products from the combustion of bio-oil were analyzed. • Microwave hydrothermal treatment can improve the combustion performance of bio-oil. [ABSTRACT FROM AUTHOR] more...

Catalyst or template-free synthesis of cerium orthovanadate (CeVO 4) nanoparticles were synthesized by simple, fast and efficient microwave assisted hydrothermal method using Ce(NO 3) 3 ·6H 2 O and NaVO 3 as the starting materials under basic pH condition. The prepared sample was characterized by powder X-ray diffraction (XRD) transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR) and Uv–Visible diffuse reflectance spectroscopy (DRS). Pure tetragonal CeVO 4 was successfully synthesized in 10 min of reaction time. The synthesized nanoparticles showed particle sizes in the range 10–20 nm and the optical absorption onset at 456 nm. The optical band gap was calculated to be 2.8 eV. The photocatalytic activity of the synthesized nanoparticles was evaluated by studying the degradation of a model dye, Eosin yellow (EY) under visible irradiation and a feasible mechanism was proposed. More than 89% of EY (60 mg/L) was degraded within 120 min. The antibacterial activity was also evaluated against Gram + ve and Gram -ve microbial pathogens. Image 1 • Tetragonal CeVO 4 nanoparticles were synthesized for the first time by microwave mediated hydrothermal method. • Photocatalytic activity of the cerium vanadate under visible light irradiation was evaluated. • Antibacterial activity of CeVO 4 against both Gram + Ve and Gram-Ve microbial pathogens has been studied. [ABSTRACT FROM AUTHOR] more...

Recycling and rapid synthesis of photocatalysts are of significant importance in wastewater degradation. Herein, a systemic strategy was developed, employing loaded nano-TiO 2 on carbon fiber (CF) utilizing microwave hydrothermal method for the fast and efficient preparation of photocatalysts. The prepared TiO 2 /CF was characterized using a variety of analytical techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS), and UV–vis. Compared with pure TiO 2 particles, TiO 2 /CF is easily recycled when employed as a photocatalyst. Nitric acid oxidation treatment of CF generates polar functional groups, which improves the bonding properties between TiO 2 and CF. With increasing CF treatment time between 0 and 4 h, the loading rate of TiO 2 increases, until TiO 2 /CF produces optimum photocatalytic activity. Moreover, the experimental results indicate that TiO 2 /CF possesses favorable photocatalytic activity, achieving 97% degradation rate of Rhodamine B within 1 h of UV light irradiation. Furthermore, even after 10 experimental cycles the photocatalyst still generates 88% degradation rate. Image 1 • The microwave hydrothermal method reduced the reaction time. • Treatment of CF surface with nitric acid enhanced loading efficiency of TiO 2 by 27.9%. • The C in CF can act as an electron trap that improves photocatalytic activity. • Reusability of TiO 2 /CF is 88% photocatalytic activity after ten cycles. [ABSTRACT FROM AUTHOR] more...