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Ball milling (BM) pretreatment combined with microwave hydrothermal (MHT) was introduced to convert corn stover into the high value-added chemical 5-hydroxymethylfurfural (HMF). Box-Behnken design and response surface methodology were used to optimize the key parameters of BM pretreatments. The BM rotational speed of 580 rpm, BM time of 360 min, and ball-to-solid ratio of 60:1 were elected firstly. Then, the pretreated corn stover was further subjected for MHT. It shows that the BM pretreated corn stover could increase the yield of HMF by about 2 times compared with the raw material. And the highest HMF yield of 3.46 ± 0.02 wt% after 150 min at 214 °C was observed. Furthermore, the potential of BM-MHT was compared with the traditional methods and the 7.5 times of superiority was verified. Finally, it was proven that the potential profit of HMF production from corn stover by BM-MHT was $26,303 per ton. BM-MHT is a promising choice for corn stover-like biomass valorization. [ABSTRACT FROM AUTHOR]

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]

The energy storage capacity of a material is primarily influenced by its specific capacitance. A series of MnxNi1-xCo2O4 at x = 0.0 – 0.10 with Δx = 0.02 was prepared using the low-temperature microwave hydrothermal (M-H) method at 160 °C, and the synthesised samples were sintered at 750 °C for 4 h. The samples were characterised by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) analysis. It is observed from X-ray diffraction that all the samples have a cubic topology belonging to the space group Fd-3m, and the average lattice constant varies from 8.049 to 8.074. The average grain size of all samples is in the range of 96 nm to 326 nm. The valence states of Mn2+, Mn3+, Ni2+, Ni3+, Co2+, and Co3+ were confirmed by X-ray photoelectron spectroscopy. The electrochemical studies using CV, GCD, and EIS were performed on all the samples. A high specific capacitance (Csp) of 490 F g−1 and high energy density and power density were reported for Mn0.06Ni0.94Co2O4, showing good electrochemical properties that are useful for supercapacitor applications. Highlights: Series of MnNCO synthesized by Microwave hydrothermal method. The average grain size is in the range of 96–326 nm. The highest Porosity of 31.17 nm is found for sample Mn0.06Ni0.94Co2O4. Higher pore size ensures more specific capacitance for the sample, x = 0.06. [ABSTRACT FROM AUTHOR]

As a thermal phase transition material, VO2 is famous for its phase transition performance. When the temperature is lower than the phase transition temperature, VO2 behaves as a semiconductor with high infrared transmittance. When the temperature exceeds the phase transition temperature, VO2 exhibits a metallic state and has a high refractive index for infrared. Regulation of phase transition temperature is key to the application of VO2. In this article, microwave hydrothermal is used to prepare VO2. H+ concentration, microwave power, annealing temperature, and annealing time are used as variable conditions to find the best preparation conditions. The preparation of samples is studied by X‐ray diffractometer, scanning electron microscope, and differential scanning calorimeter. After comparative research, the optimum preparation process of vanadium dioxide by microwave hydrothermal method is found. In addition, by varying the acidic conditions and microwave power during the preparation process, the phase transition temperature of VO2 can be regulated. [ABSTRACT FROM AUTHOR]

As a thermal phase transition material, VO2 is famous for its phase transition performance. When the temperature is lower than the phase transition temperature, VO2 behaves as a semiconductor with high infrared transmittance. When the temperature exceeds the phase transition temperature, VO2 exhibits a metallic state and has a high refractive index for infrared. Regulation of phase transition temperature is key to the application of VO2. In this article, microwave hydrothermal is used to prepare VO2. H+ concentration, microwave power, annealing temperature, and annealing time are used as variable conditions to find the best preparation conditions. The preparation of samples is studied by X‐ray diffractometer, scanning electron microscope, and differential scanning calorimeter. After comparative research, the optimum preparation process of vanadium dioxide by microwave hydrothermal method is found. In addition, by varying the acidic conditions and microwave power during the preparation process, the phase transition temperature of VO2 can be regulated. [ABSTRACT FROM AUTHOR]

Transition-metal double hydroxides offer many benefits, including abundant nanostructures, low cost, easy preparation, diverse compositions, and adjustable physicochemical properties, which have a wide range of applications and are highly promising for the development of high-performance electrode materials. Herein, hydrangea-like manganese-doped nickel–cobalt double hydroxide (NiCoDH-Mn) nanostructures were prepared through a fast one-step microwave hydrothermal method within a few minutes. A thorough analysis was conducted on how the nanostructure, crystal structure, and electrochemical properties of the samples were affected by the amount of the Mn doping content. Density functional theory (DFT) calculations demonstrated that the introduction of Mn doping can generate impurity levels around the Fermi level of NiCoDH, enhancing its electrical conductivity. At a current density of 1 A g–1, the optimized NiCoDH-Mn has a remarkable specific capacity of 107.4 mA h g–1. Even when the current density increases by 15 times, it can still maintain a high specific capacity of 66.3 mA h g–1. After undergoing 1500 cycles with a current density of 5 A g–1, the electrode's capacity remains 128%. The hybrid supercapacitor consisting of the NiCoDH-Mn cathode and mango seed-derived activated carbon anode has an impressive energy density of 47.9 W h kg–1 and a power density of 850 W kg–1. Moreover, it boasts an impressive capacitance retention rate of 87.5%, even after 5000 cycles. We offer a highly effective and speedy approach to creating high-performance transition-metal hydroxides that are ideal for energy storage systems. [ABSTRACT FROM AUTHOR]

The bimetal oxide (CoFe2O4 )/MXene composite catalyst is successfully prepared by microwaveassisted hydrothermal method to support the MXene on the CoFe2O4 and used for the activation of peroxymonosulfate (PMS). The structure, morphology and elemental valence states of the composite catalyst are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). It is found that CoFe2O4 is successfully loaded on MXene. Taking atrazine (ATZ) as the target pollutant, the effects of catalyst dosage, persulfate concentration, pH and other factors on the degradation of ATZ in the CoFe2O4/MXene activated PMS degradation system are studied. The results show that at pH=6. 35, the degradation of ATZ reaches 100% within 15 min when the amount of CoFe2O4/MXene (0. 1 g/L) and PMS (0. 37 mmol/L) are low. The quenching experiments show that both free radical and non-free radical pathways exist in the reaction system, in which SO4•−, O2•− and 1 O2 play a dominant role, which together acts on the degradation process of ATZ. This study has developed novel materials with excellent catalytic properties, which can provide new ideas for the degradation of organic pollutants by activated PMS over heterogeneous CoFe2O4/MXene catalysts. [ABSTRACT FROM AUTHOR]

This study investigates the catalytic oxidation of acetone by different crystal phases of MnO2 prepared via different methods. Compared with β-MnO2 and γ-MnO2, α-MnO2 exhibited superior catalytic activity. Moreover, as replacements for traditional hydrothermal methods and air calcination, the use of microwave hydrothermal methods and N2 calcination significantly enhanced the catalytic performance of the MnO2 catalyst. The optimal catalyst, MnO2-WN (α-MnO2 synthesized via microwave hydrothermal method and N2 calcination), converted 100% of 100 ppm acetone below 150 °C, with the CO2 yields reaching 100%. Further, the stability of the catalyst and its potential for other volatile organic compounds (VOCs) were also determined. The experimental data demonstrated that its outstanding activity primarily stemmed from the improved preparation method, enhancing the specific surface area of the catalyst, optimizing the pore structure, improving the redox performance, and generating more acidic sites and active oxygen species, thereby creating a synergistic effect. Finally, the reaction pathway of acetone oxidation on the catalyst surface has been explored. This work provides a new perspective for developing economically efficient MnOx catalysts for removing VOCs. [ABSTRACT FROM AUTHOR]

Sunlight splitting water to produce hydrogen has become a feasible solution to the energy crisis and environmental problems. As one of the most popular photocatalysts, TiO2 still has many advantages that attract many researchers. Single-atom loaded TiO2 has garnered significant attention and usage as a water splitting photocatalyst, but still there is an urgent requirement to discover a stable, efficient, and cost-effective approach to achieve stable single-atom catalysts. In this investigation, a one-step microwave hydrothermal method was employed to fabricate Pd single-atom loaded TiO2. The prepared samples exhibit particle sizes in the range of 6–7 nm, showcasing excellent dispersion and a substantial specific surface area. The Pd atoms are securely anchored, forming stable Pd–O bonds with the support material. The resulting Pd–TiO2 catalyst exhibited an impressive hydrogen evolution rate of 24.6 mmol g–1 h–1, accompanied by an AQY of 23.4% at 365 nm. This research presents a viable and economical strategy for producing single-atom loaded catalysts with high efficiency. [ABSTRACT FROM AUTHOR]

An environmentally benign, economically advantageous microwave hydrothermal approach is used in synthesis of desirably tailored graphene oxide–induced p-NiO/n-MoO3 (GNM) heterostructures. Various analytical techniques such XPS, XRD, UPS, EIS, and Mott-Schottky were conducted to comprehend complete morphology and functioning of the novel ternary heterostructure photocatalysts. Also, SEM and HR-TEM images were presented for better interpretation. The strategic plasmonic step scheme (S-scheme) charge migration approach was used to describe the effective charge recombination process. Hydroxyl and oxide active species were corollaries of the reactive radical-scavenging experiments and electron spin resonance. The work function has been confirmed using ultraviolet photoelectron spectroscopy (UPS), which assessed an electron transfer between NiO and MoO3, yielding work function values of 6.32 eV and 5.26 eV, respectively. The cell apoptosis of the HeLa cell line approves the material's biocompatibility. Cyclic voltammetry and electrochemical impedance spectroscopy reveal electrochemical performance of GNM heterostructures. We anticipate our results would pave the way for current and future applications. In order to ensure eco-restoration such photocatalyst which are eco and cost friendly are synthesized. Assessment of pollutant risks presents the impact of them on human and terrestrial and aquatic animals. Sustainability of material is acknowledge as they use solar light for photocatalysis and dye degradation, and hence can be green material. One such material for the treatment of wastewater, dye-infused waters, and industrial water has been tailored, which is capable of dye degradation, heavy metal, and other pollutant removal. Very importantly, the synthesized material is a biocompatible one. [ABSTRACT FROM AUTHOR]

The development and utilization of biomass and agroforestry processing byproducts for high-value applications have been an important topic in the field of renewable materials research. Based on this, a two-step microwave hydrothermal pre-carbonization and KOH activation method was proposed to synthesize tannin-based activated carbons with a high specific surface area, hierarchical pore structure, and good electrochemical performance. The microstructure, texture properties, and physicochemical characteristics were investigated. The results show that the prepared tannin-based activated carbons presented a hierarchical pore structure (micro- and mesopores) with a specific surface area as high as 997.46 m³ g-1. The electrochemical analysis shows that the tannin-based activated carbons have good wettability and charge transfer rates. Under the three-electrode system with 6 M KOH as the electrolyte, the active material TAC600-4 had a maximum specific capacitance of 171 F g-1 at 0.5 A g-1. As the current density increases to 10 A g-1, the specific capacitance can still be maintained at 149 F g-1, indicating a good rate capability. Therefore, the specific surface area and pore size of tannin-based activated carbons can be effectively adjusted by the alkali/carbon ratio, making it a promising supercapacitor electrode material and providing a new method for the high-value development of tannins in the field of electrochemical energy storage. [ABSTRACT FROM AUTHOR]

Inflammation is thought to impact the wound healing pathology and is highly related to many chronic wounds which do not heal. Natural derived herbs with anti-inflammation effects have gained attention with their availability and affordability for clinical treatment. In this study, the ginger (Zingiber officinale) -derived carbon dots (GCDs) were prepared by a green, fast, low-cost microwave-assisted hydrothermal approach at 180 °C by using ginger aqueous as the only precursor without any organic reagent or surface passivation agents. The GCDs showed a small size distribution with the mean particle size of 2.3 nm, enable emit intense blue photoluminescence and exhibited good biocompatibility. The GCDs was successfully applied in a bio-imaging in vitro. Accelerating wound healing by high anti-inflammatory activity was verified both in vivo and in vitro. Moreover, the GCDs effectively blocked the toll-like receptor 4 (TLR4)-mediated nuclear factor-kappa B (NFκB) pathway to significantly dephosphorylate IκBα and inhibited the nuclear translocation of p65 protein, which reduced the expression of proinflammatory factors. On the mRNA levels, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) and Nitric oxide (NO) were decreased, and the inhibition rate were 51.6%, 81.7%, 86.0%, and 58.7%, respectively, all of which indicated excellent anti-inflammatory effect of the GCDs. Therefore, fluorescent GCDs have a promising application as an imaging tool and functional wound dressing for wound clinical management. The study also brings a new idea for the discovery of effective special substances that is not limited to bioactive small-molecule compounds. [Display omitted] [ABSTRACT FROM AUTHOR]

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]

Wollastonite (CaSiO 3) is a well-known rock-forming mineral and an important constituent in ceramics and cement industries due to its outstanding mechanical, chemical, and thermal stabilities. Despite technological importance, functional properties such as photon upconversion in CaSiO 3 wollastonite ceramics have not been studied. In this contribution, Yb- and Er-doped CaSiO 3 (Yb/Er–CaSiO 3) wollastonite ceramics were synthesized via microwave hydrothermal technique followed up by heat-treatment in an air environment. X-ray diffraction and transmission electron microscopy studies confirmed the β-wollastonite (2M) phase in the synthesized samples heat-treated at 1050 °C. X-ray photoelectron spectroscopy analysis has shown that the binding energy of Ca 2p orbitals decreases after doping, indicating a change in the crystal environment of Ca in the CaSiO 3 and hence a successful incorporation of Yb3+ and Er3+ ions in the lattice. The 980 nm excitation resulted in ultraviolet, violet and strong green and red upconversion emissions as well as downshifting infrared emissions due to the energy transfer between Yb3+ and Er3+ ions. An absolute upconversion quantum yield in the 400–800 nm range is 0.04%. The most intense phonon band was observed at 969 cm−1 in the Yb/Er–CaSiO 3 system. This study demonstrates that the β-wollastonite can be developed as a new kind of efficient upconversion phosphor material. [ABSTRACT FROM AUTHOR]

The complex and compact structure of straw represents the primary obstacle to its high-value conversion. This research integrated ball milling depolymerization, microwave hydrothermal conversion and machine learning methodology to gradually optimize and enhance the conversion potential of straw to 5-hydroxymethylfurfural (HMF). The findings indicated that the HMF yield of from straw, following ball milling depolymerization and direct microwave hydrothermal conversion, ranges between 0.10% and 0.45%. However, under acid-catalyzed microwave hydrothermal conditions, the HMF yield markedly increased to 2.35%–2.95%. It was noteworthy that AlCl 3 , Ca-zeolite, and Mg-zeolite increased the maximum HMF yield to 9.47%, 7.67%, and 9.04%, respectively. Based on these findings, introducing organic solvents to form a biphasic system could further increase the HMF yield to 10.63% (75% MIBK addition scenario). Finally, machine learning prediction indicated that the HMF yield could be optimized to 11.13 wt% in the biphasic system with 0.08 g AlCl 3 per 0.2 g reaction material and 7.5 mL MIBK per 10 mL reaction solution and pH 1.25 under microwave hydrothermal at 190 °C for 0.75 min. The findings of this study provide a valuable reference point for the upcycling of straw and other biomass wastes, thereby facilitating the development and utilization of renewable resources. [Display omitted] • A method to optimize the HMF yield from straw conversion was proposed. • The synergic use of organic solvent and catalyst optimize the HMF yield. • Machine learning optimize the HMF yield, and it be increased to 11.13 wt%. • The machine learning method is applicable to other solid wastes conversion HMF. [ABSTRACT FROM AUTHOR]

Objective To prepare a copper-nobium antibacterial coating on a titanium surface by a microarc oxidation-microwave hydrothermal two-step method and to study its surface structure and antibacterial properties. Methods Using titanium coated with a microarc oxidation coating (MAO group) as the substrate, copper and niobium were introduced by a microwave hydrothermal method in low (MHL-Cu group), medium (MHM-Cu group) and high (MHH-Cu group) copper chloride solutions and niobium oxalate (MH-Nb group) solutions, respectively. The component with the highest copper content was determined by energy spectrum analysis, and the copper-niobium composite coating (MH-Cu/Nb group) was prepared by microwave hydrothermal mixing with niobium oxalate. The microstructure, element distribution and phase composition of the specimens were characterized by scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction, and the bacteriostatic effect of the coating onEscherichia coliand Staphylococcus aureus was determined by the film method. Results Energy dispersive spectrometry showed that Cu was introduced onto the surface of the MHL-Cu, MHM-Cu, and MHH-Cu groups, and the atomic ratios of copper in each group were （0.68 ± 0.04）%,（1.17 ± 0.06）%, and （1.64 ± 0.03）%. The difference between groups was statistically significant (P< 0.01). Scanning electron microscopy showed a crater-like porous structure on the surface of the MAO group, and the MHL-Cu, MHM-Cu, MHH-Cu, MH-Nb, MH-Cu/Nb groups maintained micropore morphology. The roughness increased with increasing Cu2+ concentration, in which the MH-Nb and MH-Cu/Nb groups showed gully like structures simultaneously. X-ray diffraction showed that the coating of the MAO group was mainly composed of titanium and anatase phase TiO2, and the coatings of the MHL-Cu, MHM-Cu, MHH-Cu, MH-Nb, MH-Cu/Nb groups were mainly composed of anatase and rutile phase TiO2. Compared with the MAO group, Escherichia coli and Staphylococcus aureus in the MHH-Cu, MH-Nb, MH-Cu/Nb groups decreased to varying degrees, with significant differences (P< 0.001); compared with the MH-Cu/Nb group, the colony number difference had statistical significance (P> 0.05).Conclusion The rough, porous coating containing copper and niobium prepared by the microarc oxidation-microwave hydrothermal two-step method can effectively inhibit the growth ofEscherichia coli and Staphylococcus aureus.

In this work, highly dispersed atomically-thin MoS2 nanosheets were fabricated at one thousandth of the commercial cost using sepiolite (SEP) mineral nanofibers as carriers via a microwave hydrothermal method. Atom-resolved microscopy revealed the MoS2 nanosheets were only 1–4 atomic layers thick. The Mo atoms anchored on the mineral surface served as nucleation sites for the nanosheet growth. The MoS2 layers were in staggered stacking yielding abundant atomic steps at the nanosheets’ edges, where catalytically active molybdenum terminations dominated instead of the inert sulfur atoms commonly reported. DFT calculations disclosed that the bonding of Mo(MoS2) and O (SEP) at the MoS2/sepiolite (MSEP) interface enabled SEP to be a unique support, superior to the other minerals for growing such highly-dispersed ultrathin MoS2 architecture. In a typical photocatalyisis application, the MSEP demonstrated a significantly improved photocatalytic performance for RhB degradation compared with the MoS2 nanosheets assembled microspheres. This work provides an important new strategy for low-cost batch preparation of high quality 2D materials via assembly on mineral materials.

Currently, perovskite solar cells (PSCs) have achieved photoelectric conversion efficiencies (PCEs) comparable to silicon-based and GaAs solar cells. However, PSCs show relatively poor long-term stability, which inhibits their commercialization. Therefore, researchers have turned to inorganic hole-transport materials (HTMs) with more stable chemical properties, such as CuGaO2. It is well known that inorganic HTMs have uneven coverage and show agglomeration in thin films. This study is the first report of growing CuGaO2 nanosheet arrays (CGO arrays) using a simple, low-cost, and reproducible microwave hydrothermal method. This material acts as a hole-transport layer for inverted PSCs, which increases the hole extraction area and efficiency. Remarkably, the devices based on the CGO arrays showed excellent performance in terms of thermal stability and moisture corrosion resistance. After thermal aging in the glovebox for 240 h, the device still maintained more than 78% of the initial efficiency. After 400 h of storage in an environment with a humidity of 50–80%, the device retained more than 83% of its initial efficiency. Consequently, in this study, the CGO arrays were able to reduce the impact of the external factors on the device life of PSCs to maintain an efficient and stable output. [ABSTRACT FROM AUTHOR]

MgAl2O4 was synthesized by microwave hydrothermal method and coprecipitation method, respectively. X-ray diffractometer (XRD), scanning electron microscope (SEM), BET, Archimedes method and an automatic micro-Vickers hardness tester were used to characterize the phase composition, microstructure, powder activity, relative density, and hardness of MgAl2O4. The results showed that, compared with the microwave hydrothermal synthesis method, the powder synthesized by the coprecipitation method was purer, the particle size was smaller and the distribution was more uniform, and the particles had no agglomeration phenomenon. The specific surface area of the powder synthesized by the coprecipitation method was 79.011 m2/g, three times larger than the powder synthesized by microwave hydrothermal synthesis. The optimum sintering temperature of MgAl2O4 synthesized by coprecipitation method or microwave hydrothermal method is 1700 °C. At this temperature, the sintered sample synthesized by coprecipitation method has the densest microstructure, the relative density is 98.83% and the hardness is 1411 kgf/mm2; while the relative density of the sintered sample synthesized by the microwave hydrothermal synthesis method is 92.77% and the hardness is 1407 kgf/mm2. [ABSTRACT FROM AUTHOR]

SnO2@C/graphene ternary composite material has been prepared via a double-layer modified strategy of carbon layer and graphene sheets. The size, dispersity, and coating layer of SnO2@C are uniform. The SnO2@C/graphene has a typical porous structure. The discharge and charge capacities of the initial cycle for SnO2@C/graphene are 2,210 mAh g−1 and 1,285 mAh g−1, respectively, at a current density of 1,000 mA g−1. The Coulombic efficiency is 58.60%. The reversible specific capacity of the SnO2@C/graphene anode is 955 mAh g−1 after 300 cycles. The average reversible specific capacity still maintains 572 mAh g−1 even at the high current density of 5 A g−1. In addition, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) are performed to further investigate the prepared SnO2@C/graphene composite material by a microwave hydrothermal method. As a result, SnO2@C/graphene has demonstrated a better electrochemical performance.

Lithium sulfur (Li-S) battery has exhibited great application potential in next-generation high-density secondary battery systems due to their excellent energy density and high specific capacity. However, the practical industrialization of Li-S battery is still affected by the low conductivity of sulfur and its discharge product (Li2S2/Li2S), the shuttle effect of lithium polysulfide (Li2Sn, 4 ≤ n ≤ 8) during charging/discharging process and so on. Here, cobalt disulfide/reduced graphene oxide (CoS2/rGO) composites were easily and efficiently prepared through an energy-saving microwave-assisted hydrothermal method and employed as functional interlayer on commercial polypropylene separator to enhance the electrochemical performance of Li-S battery. As a physical barrier and second current collector, the porous conductive rGO can relieve the shuttle effect of polysulfides and ensure fast electron/ion transfer. Polar CoS2 nanoparticles uniformly distributed on rGO provide strong chemical adsorption to capture polysulfides. Benefitting from the synergy of physical and chemical constraints on polysulfides, the Li-S battery with CoS2/rGO functional separator exhibits enhanced conversion kinetics and excellent electrochemical performance with a high cycling initial capacity of 1,122.3 mAh g−1 at 0.2 C, good rate capabilities with 583.9 mAh g−1 at 2 C, and long-term cycle stability (decay rate of 0.08% per cycle at 0.5 C). This work provides an efficient and energy/time-saving microwave hydrothermal method for the synthesis of functional materials in stable Li-S battery.

Environmental pollution by organic pollutants is a serious concern which may be solved by photocatalytic degradation of pollutants, yet the efficiency of actual photocatalytic materials is limited. For instance, conventional MoS2 nanosheets tend to agglomerate, which hinders the access of pollutants to active sites. To overcome this challenge, we hypothesized that assembling MoS2 nanosheets on a mineral support would improve access to active sites. We synthesized a catalyst made of 3–4 atomic layers of MoS2 nanosheets deposited on tourmaline using a microwave hydrothermal method. Results show that tourmaline occurs as a polyhedron single crystal that supports the epitaxial growth of 2H-MoS2 layers on tourmaline (77 3 ¯ ) facets, while an intrinsic rolling up behavior of MoS2 layer from [002] to [106] on the mineral surface accounts for the curly morphology. The pangolin-like MoS2/tourmaline composite degrades rhodamine B much better than the pure MoS2 nanosheets assembled microspheres. This is explained by the reduced thickness of MoS2 nanosheets according to the density functional theory. Overall, our findings represent a new tactic for the cost-effective batch preparation of two-dimensional materials with high catalytic performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bimetallic metal-organic frameworks (Zn/Ti-MOF) were synthesized via microwave hydrothermal method. • C-doped ZnO/TiO 2 particles were successfully synthesized by one-step controllable pyrolysis of Zn/Ti-MOF. • The as-prepared C-doped ZnO/TiO 2 exhibited a higher Rhodamine B photocatalytic degradation activity. • The possible mechanism for the photocatalytic process of C-doped ZnO/TiO 2 was proposed. A series of C-doped ZnO/TiO 2 composites with various molar ratios of ZnO to TiO 2 were synthesized by one-step controllable pyrolysis of Zn/Ti bimetallic metal-organic frameworks (Zn/Ti-MOF). The Zn/Ti-MOF was prepared using a facile microwave hydrothermal method. Electron microscopic analysis proved that the composites presented regularity cubic morphology with an edge length of about 1 μm and the C atoms were successfully doped into ZnO/TiO 2 composites. X-ray photoelectron spectroscopy (XPS) measurement results confirmed the C-doping in the ZnO/TiO 2. Comparative experimental studies showed that 2% ZnO/TiO 2 composites prepared with the calcination temperature of 600℃ displayed the best photocatalytic degradation efficiency (94%) of RhB under the simulated sunlight irradiation. Cyclical experiment indicated the high stability and reusability of 2% ZnO/TiO 2 composites. Electron spin resonance (ESR) and trapping experiments illustrated that the produced O 2 − served as the main active species for the efficient RhB removal. This work provides an efficient way for preparing C-doped bimetal oxides composites, which would have an important application prospect in the photocatalytic degradation of organic pollutants in environmental water. [ABSTRACT FROM AUTHOR]

Lignocellulose based nanomaterials are emerging green biosolids commonly obtained from wood pulp. Alternative feedstocks, such as as unavoidable food waste, are interesting resources for nano/microfibers. This research reports the production and characterization of microfibrillated lignocellulose (MFLC) from cassava peel (CP) and almond hull (AH) via acid-free microwave-assisted hydrothermal treatment (MHT) at different temperatures (120–220 °C). During processing, the structural changes were tracked by ATR-IR, TGA, XRD, 13C CPMAS NMR, zeta potential, HPLC, elemental analysis (CHN; carbon, hydrogen and nitrogen), TEM and SEM analyses. The microwave processing temperature and nature of feedstock exerted a significant influence on the yields and properties of the MFLCs produced. The MFLC yields from CP and AH shifted by 15–49% and 31–73%, respectively. Increasing the MHT temperature substantially affected the crystallinity index (13–66% for CP and 36–62% for AH) and thermal stability (300–374 °C for CP and 300–364 °C for AH) of the MFLCs produced. This suggested that the MFLC from CP is more fragile and brittle than that produced from AH. These phenomena influenced the gelation capabilities of the fibers. AH MFLC pretreated with ethanol at low temperature gave better film-forming capabilities, while untreated and heptane pretreated materials formed stable hydrogels at solid concentration (2% w/v). At high processing temperatures, the microfibrils were separated into elementary fibers, regardless of pretreatment or feedstock type. Given these data, this work demonstrates that the acid-free MHT processing of CP and AH is a facile method for producing MFLC with potential applications, including adsorption, packaging and the production of nanocomposites and personal care rheology modifiers. [ABSTRACT FROM AUTHOR]

• MoS 2 nanoflowers with 1T/2H phase were prepared by microwave hydrothermal method for electromagnetic wave absorption. • Microwave hydrothermal method reduced the reaction time of the synthesis of molybdenum disulfide. • Best electromagnetic wave absorption performance was achieved at mass ratio of 1T:2H = 1:1. • Electromagnetic wave absorption performance at a thickness of 2.8 mm is up to −64.9 dB. • With the increase of 1T phase and heterointerfaces, improve polarization and conduction losses. Interface engineering and phase engineering play crucial roles in enhancing the design and development of advanced electromagnetic wave (EMW) absorbers. However, there is a lack of focus on designing phase structures and interfaces from a microscopic perspective to adjust impedance matching and EMW absorption. This study introduced a competitive strategy involving 1 T/2H MoS 2. The phase structure and composition of MoS 2 were controlled using a microwave hydrothermal method. By creating a diverse phase interface within the material in the form of 1 T/2H, a balance between conduction loss and polarization loss was achieved, leading to improved EMW absorption through enhanced impedance matching. The results indicated that the incorporation of the 1 T phase boosted the electron transfer capability of MoS 2 , increasing conduction loss. The 1 T/2H phase interface enhanced interface polarization, thereby amplifying polarization loss. At a thickness of 2.8 mm, the absorber demonstrated a minimum reflection loss of −64.9 dB and an effective absorption bandwidth of 4.6 GHz. In far-field conditions, the maximum radar cross-section (RCS) of the 1 T/2H phase MoS 2 nanoflowers was −27.5 dBm2. This study elucidates the relationship between 1 T/2H phase MoS 2 content and phase interfaces with impedance matching, offering a novel approach for developing high-performance MoS 2 -based EMW absorbing materials. [ABSTRACT FROM AUTHOR]

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]

In this study, we fabricated a nano/micro cavity-like hierarchical architecture of WS 2 /α-NiMoO 4 composite using microwave hydrothermal and calcination processes. The composite was characterized by X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, elemental mapping, and X-ray photoelectron spectroscopy. The electrochemical measurements of the WS 2 /α-NiMoO 4 composite electrode for application in supercapacitors (SCs) were performed through cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. The WS 2 /α-NiMoO 4 nanocomposite exhibited a specific capacity of 460 F g-1 at 1 A g-1 current density and a capacitor retention of 92% after 2000 cycles. However, α-NiMoO 4 spherical nanoparticles had a specific capacity of 231 F g-1 at 1 A g-1 current density and capacitor retention of 73% after 2000 cycles. The excellent specific area, formation of cavity-like structures, increase in pore size, superior electrical conductivity, and robust stability of WS 2 /α-NiMoO 4 enhanced the effectiveness of the electrode composite material for supercapacitor application. [ABSTRACT FROM AUTHOR]

• Heterogenous Co 3 O 4 nanosphere/Co(OH) 2 nanosheet hybrid has been synthesized. • PVP acts as a controlling reagent to modulate the phase structure of the Co 3 O 4 and Co(OH) 2. • The effect of molecular weight of PVP has been investigated. • The Co 3 O 4 /Co(OH) 2 hybrid exhibits an excellent capacitive performance. In this study, we developed a facile chemical precipitation approach for the synthesis of heterogeneous Co 3 O 4 nanosphere/Co(OH) 2 nanosheet hybrids in the presence of polyvinylpyrrolidone (PVP) as a phase-controlling reagent. The crystalline phase and morphology of the product varied upon changing the chain length of PVP (from 8k to 120k), with short-chain PVP favoring the formation of Co 3 O 4 nanospheres and long-chain PVP favoring the synthesis of Co(OH) 2 nanosheets. Accordingly, heterogeneous Co 3 O 4 /Co(OH) 2 hybrids of various blending ratios were readily prepared in the presence of PVP of different molecular weights. The molecular weight of PVP also affected the electrochemical properties of the Co 3 O 4 nanosphere/Co(OH) 2 nanosheet composites. When using PVP of moderate chain length (58k), the resultant Co 3 O 4 /Co(OH) 2 composite exhibited the optimal supercapacitive performance, characterized by an excellent specific capacitance of 771.2 F g−1 at 1 A g−1, and retained approximately 68.5% of this capacitance when operated at a high current density of 10 A g−1. Furthermore, this composite displayed an excellent charge/discharge cycling life at a current density of 4 A g−1, with a capacitance retention of 93.3% after 3000 repeated cycles. [ABSTRACT FROM AUTHOR]

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]

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]

• Bandgap-graded ZnO/Zn x Cd 1−x S/CdS has been successful prepared. • CdS both used as photo-absorber and light reflection material. • CdSe quantum dots has been deposited on composite nanostructure. • A novel chemical solar cell has been prepared. Effective interfaces composed of smart materials could play a critical role in the rapid transfer and separation of charges to achieve the high power-conversion efficiency of solar cells. In this work, we report an efficient chemical solar cell that uses a ZnO/Zn x Cd 1−x S/CdS structure, modified with CdSe deposited with a microwave hydrothermal technique, for rapid transport of charges using a frame construction to allow for reuse. The morphology, nanostructure, and reaction mechanisms of CdS nanorods and the Zn x Cd 1−x S layer were systematically investigated. The results indicated that light absorption expands from 550 nm of CdS to 700 nm because of the absorption of nearly all the visible light by deposited CdSe quantum dots. The effects of the compositional structure on cell performance are investigated to reveal the enhancement mechanism, which is mainly attributed to the suitable nano-branch structure, high light absorbability, low charge transfer resistance, and low recombination rate. This work demonstrates a potential universal method of designing an interface with a multi-component composite for efficient charge transport and separation, not only in chemical solar cells but with extensions to photocatalysis and water splitting uses as well. [ABSTRACT FROM AUTHOR]

Flower-like copper oxide (CuO)/nitrogen-doped reduced graphene oxide (N-rGO) was synthesized through a one-pot microwave hydrothermal method by using polyvinylpyrrolidone (PVP) as surfactant. In the process, in situ formation of nanomaterial CuO, reduction of graphene oxide and doping of nitrogen species occurred simultaneously in urea solution. The structural and surface properties of the material were investigated by field emission scanning electron microscopy (FESEM) and transmission electron microscopies (TEM), the energy dispersive spectroscopic (EDS) and powder X-ray diffraction (XRD). This showed the flower-like CuO with an interconnected architecture was successfully uniformed and grown on the surface of N-rGO. Moreover, the surfactant PVP and urea were found to be the key factors to control the morphology of the CuO nanostructure. Electrochemical investigations indicated that the CuO/N-rGO composite exhibited a significantly enhanced ORR activity in comparison to pure CuO and N-rGO in an alkaline solution. The enhancement in ORR activity of CuO/N-rGO composite can be attributed to the synergistic effects of good electron transport from N-rGO as well as abundance of exposed catalytic sites and meso/macroporosity from CuO nanostructures. Flower-like CuO/N-rGO hollow microsphere composite was successfully synthesized through a one-pot microwave hydrothermal method by using polyvinylpyrrolidone as surfactant. The surfactant and urea were the key factors in controlling the morphology of the copper oxide nanostructure. The CuO/N-rGO composite demonstrated a significantly enhanced ORR activity in comparison to the pure CuO and N-rGO in an alkaline solution. The CuO/N-rGO composites also exhibited superior durability to Pt/C. [ABSTRACT FROM AUTHOR]

CoAl 2 O 4 /kaolin hybrid pigments with high blue value were prepared via microwave hydrothermal assisted technique. The obtained hybrid pigments incorporated 60 wt% kaolin presented excellent color properties (L ⁎ = 34.44, a ⁎ = 16.73, b ⁎ = −70.49) after being calcined at 900 °C, which was matched with the organic Phthalo Blue. In particular, the hybrid pigments could be well dispersed into acrylonitrile butadiene styrene, and the tensile strength, bending strength and impact strength of acrylonitrile butadiene styrene increased by 27%, 48.7% and 50% as the added amount of CoAl 2 O 4 /kaolin hybrid pigments was 2 wt%, respectively. Therefore, the as-prepared hybrid pigment could be served as a coloring agent and reinforced materials for enhancement the mechanical and thermal stability properties of acrylonitrile butadiene styrene. Due to the favorable dispersion in acrylonitrile butadiene styrene matrix, hybrid pigments also were applied in 3D printing. Unlabelled Image • CoAl 2 O 4 /kaoline hybrid pigments were prepared via microwave hydrothermal method. • Hybrid pigment presented excellent color properties (L ⁎ = 34.44, a ⁎ = 16.726, b ⁎ = −70.486). • Acrylonitrile butadiene styrene containing hybrid pigment presents good thermal stability. • Hybrid pigments can be used as coloring agent and reinforced material in plastic. [ABSTRACT FROM AUTHOR]

Watermelon peelis a typical biomass waste, which is stacking with a speed of 70 million tons per year in China. While at the same time, watermelon peel is mainly disposed by landfilling or incinerating with other waste, leading to secondary pollution and a squandering of resources. Therefore, using advanced green technology, biomass wastes represented by watermelon peel can be effectively transformed into environmentally friendly alternative resources. In this study, watermelon peel was selected as typical biomass waste to explore the resource potential of microwave hydrothermal (MHT) treatment under drying, acid and alkali treating process. This work simultaneously considered the solid phase products and liquid phase products after MHT treatment. Results showed that when the MHT temperatures were between 130 °C and 190 °C, the yield of hydrochar could reach 86.01% after alkali treatment (170 °C), significantly higher than that in drying treatment and acid treatment. However, its calorific value was lower than 17 MJ/kg, which means it had no potential to be a fuel. Meanwhile, drying and acid treatment could not only obtain hydrochar conforming to standard coal whose high heating value is in range of 17-28 MJ/kg, but more importantly, high value-added 5-hydroxymethylfurfural (HMF) and furfural (FF) could be obtained in liquid phase products. The yields of HMF and FF in these treatments were significantly affected by MHT temperature. The results of Fourier Transform infrared spectroscopy indicated that the watermelon peel was hydrolyzed and decarboxylated under MHT conditions after drying and acid treatment, and became more intense with increasing temperature. The decrease of pH and the leaching efficiency of total organic carbon with the increase of MHT temperature can also reflect the intensification of hydrolysis reaction and decarboxylation reaction. In addition, the SEM image showed that a large number and size of microspheres appeared on the surface of the hydrochar obtained by the drying treatment and the acid treatment, which may affect the performance of the hydrochar and the yield of HMF. Moreover, the acid treatment can obtain a higher HMF yield of 3.3 % under MHT temperature of 130 °C at a low energy consumption as compared with the drying treatment. This means that 33 kg of HMF can be obtained by treating one ton of dried watermelon peel under this condition. According to the market price of HMF, the value is 165 182 yuan which means that the economic value of processing a ton of fresh watermelon peel is 6 607 yuan. In addition, the hydrochar yield of 25.96% obtained by acid treatment under corresponding MHT temperature also showed its economic value due to the market price of standard coal (700 yuan per ton). In addition, the simple economic calculation shows that the energy consumption of the process for treating 1 ton of fresh watermelon peel is only 66 yuan. The superiority of acid treatment on the transformation of watermelon peel resources was explained. Therefore, from the perspective of comprehensive economic output and input, the process has great potential for industrial application. [ABSTRACT FROM AUTHOR]

Abstract Carbon dots (CDs) as a kind of environment-friendly fluorescent nanomaterial has been actively studied because of wide and potential applications, such as bioimaging and biosensors. It is worth mentioning that preparing CDs from the recycling of carbonaceous waste has received considerable research interest. We proposed a simple carbon dots synthesis technique, that is, using China grass carp scales (CGCS) as original and green materials by a one-step microwave hydrothermal method to prepare CDs. Since the mercury ion has strongly sulphophile, S atoms display higher thermodynamic affinity and faster integrating process with Hg2+ ions. Due to the presence of large amount of cysteine-containing sulfhydryl groups, the obtained CGCS-CDs can be used as a specific fluorescence probe for detecting Hg2+ ions. Subsequently, CGCS-CDs were characterized by HR-TEM, XRD, FT-IR and XPS analyses. The optical properties of CGCS-CDs were elucidated by fluorescence and UV–vis spectra. Additionally, the effects of pH values and salt concentrations on optical properties of CGCS-CDs were also researched by fluorescence spectra. Under optimal conditions, the decrease of fluorescence intensity displays a good linear relationship with allowable Hg2+ ion detection concentration range of 0.014–30 μmol/L and a limit of detection (LOD) of 0.014 μmol/L is acquired. Meanwhile, the effect of other metal ions on the detection of Hg2+ ions by using CGCS-CDs as fluorescence probe was studied, suggesting that the CGCS-CDs could be an excellent fluorescence probe for the detection of Hg2+ ions. Eventually, the CGCS-CDs were proven to be low toxicity and applied for Hg2+ ions detection in lake water and cosmetic, demonstrating their potential towards diverse applications. Graphical abstract China grass carp scales (CGCS) are used as an original and green materials to prepare carbon dots (CDs) by a one-step microwave hydrothermal method. The obtained China grass carp scales-carbon dots (CGCS-CDs) can be used as a specific fluorescence probe in detection of Hg2+ ion for the first time. Under optimal conditions, the decrease of fluorescence intensity displays a good linear relationship in permitted detection concentration range of Hg2+ ion from 0.014 to 30 μmol/L and a limit of detection of 0.014 μmol/L was acquired. Meanwhile, the effect of other metal ions on the detection of Hg2+ ion by using CGCS-CDs as fluorescence probe was studied, suggesting that the CGCS-CDs could be an excellent fluorescence probe for the detection of Hg2+ ion. CGCS-CDs were proven to be low cytotoxicity and applied for Hg2+ ions detection in lake water and cosmetic, demonstrating their potential towards diverse applications. Unlabelled Image Highlights • Sulfur-rich China grass carp scale (CGCS) are used to prepare carbon dots (CDs). • Prepared CGCS-CDs possess relatively high fluorescent quantum yield (19.92%). • CGCS-CDs can combine with Hg2+ ions sensitively, specifically and efficiently. • CGCS-CDs can be used as fluorescence probe to detect Hg2+ in factual applications. [ABSTRACT FROM AUTHOR]

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]

A novel microwave hydrothermal method was developed to prepare highly dispersed W/Al2O3 catalysts, in which WO3 was deposited on alumina via precipitation between tungstate and nitric acid under microwave hydrothermal environment and oxalic acid was used as an additive. Moreover, the role of oxalic acid was investigated by varying its amount and the addition method. It is found that the catalysts show higher WO3 dispersion and weaker W–Al interaction than that prepared by the conventional impregnation method. The hydrothermal period can be extremely reduced to a few minutes, and highly dispersed WO3 can be achieved even without oxalic acid. When oxalic acid was added after the formation of H2WO4, it mainly acts as a modifier for reacting with the hydroxyl groups on alumina and has little effect on WO3 dispersion. When oxalic acid was divided into two parts, one for pretreating alumina and the remains for preventing the aggregation of H2WO4, it may effectively act as both dispersant and modifier, leading to further increased WO3 dispersion and weakened W–Al interaction. The catalysts prepared by the microwave hydrothermal method show superior dibenzothiophene hydrodesulfurization activity. This method provides rapidity, convenience and cost effectiveness for preparing active hydrotreating catalysts.

Semiconductor-based heteronanostructures with the high carriers-flow steering and high activity and stability in the visible-light-driven multicomponent photocatalytic system have been of great concern due to its long-standing demand in the wide application of environmental protection and energy conversion. However, the construction of ternary-component nanocrystals usally undergos multiple complex steps to restrict its application. In the work, we successfully report the facile design and synthesis of a novel double Z-scheme Zn 3 (VO 4 ) 2 /Zn 2 V 2 O 7 /ZnO ternary heteronanostructure system (THS) via self-phase transition with heating on basis of the Zn 3 (OH) 2 V 2 O 7 ·2H 2 O precursor in a low-cost microwave hydrothermal assistant, which exhibited excellent photocatalytic performances. In this case, the employment of Zn 3 (OH) 2 V 2 O 7 ·2H 2 O as the heteronanostructure precursor is the key for fabricating the THS material, which not only boosted the interaction with its structure and but also maintained the mesoporous nanosheet structure. It has been proved that Zn 3 (OH) 2 V 2 O 7 ·2H 2 O firstly lost it H 2 O and then the partial Zn 3 (VO 4 ) 2 underwent the self-phase transition process to produce Zn 2 V 2 O 7 and ZnO (Zn 3 (OH) 2 V 2 O 7 ·2H 2 O → Zn 3 (VO 4 ) 2 → Zn 2 V 2 O 7  + ZnO), which obtained the double Z-scheme THS. Accordingly, the interfacial-dominated photocatalysis reactivities such as the removal of phenols and dyes were used as ideal experiments to verify the responsibility of the constructed double Z-scheme THS material that was equipped with the narrow band gap, intimate contact interface, the wide visible light absortion and more efficient charge transfer and separation for high visible-light photocatalytic reactivity and stable cycling. PL spectra, radicals trapping experiments and ESR tests confirmed that the nontraditional transport of photoinduced h + and e − caused by double Z-scheme mechanism played an important role in the efficient removing the target pollutants. Such a synthetic approach maybe render double Z-scheme THS to advance the development for large-scale applications of the hetero-transition metal vanadates. [ABSTRACT FROM AUTHOR]

A new approach (microwave-hydrothermal plus oxidation) was proposed for the preparation of the Zn-based sorbents supported on the ordered mesoporous Si-based material. The hydrothermal synthesis and oxidation conditions of the sorbent precursor (ZnS/MCM41 mesophase) with Zn(AC) 2 and thioacetamide (TAA) as the Zn and S sources, respectively, were optimized. The sorbents were evaluated in a fixed bed using the simulate gas of 2000 ppm H 2 S, 39% H 2 , 27% CO, 12% CO 2 , and N 2 as balance gas. The structure of the sorbents was characterized by means of XRD, N 2 adsoprtion, SEM, EDX, and TEM analysis. The results indicate that the optimal microwave-hydrothermal conditions are 400 W, 2.5 h, and 1:3 (the mole ratio of the Zn(AC) 2 to TAA). The oxidation of ZnS in the sorbent precursor to ZnO is invalid at 550 °C due to unfavorable reaction kinetics. Both the fresh and used sorbents show ordered hexagonal mesoporous structure. It is confirmed that Zn 2 SiO 4 present in the fresh and regenerated sorbents could be consumed during the desulfurization process via the reaction (Zn 2 SiO 4  + 2H 2 S → 2ZnS + SiO 2  + 2H 2 O), giving a positive effect on the desulfurization of the sorbents. The optimized Zn-based mesoporous sorbent (actual Zn content: 20.3%) exhibits superior (high breakthrough sulfur capacity: 5.4–5.7%) and stable desulfurization ability during five sulfidation/regeneration cycles. In addition, sulifidation reaction only leads to low-degree plugging of the pore structure of the regenerated sorbents, and the regeneration reaction could restore (at least mostly) the aforementioned changes in the pore properties. [ABSTRACT FROM AUTHOR]

Dye-sensitized solar cells (DSSCs) have been emerging as a potential alternative to photovoltaic devices, which convert incident light into electric energy. However, the power conversion efficiency of DSSCs is currently too low for them to be used in commercial applications. Hence, further improvements in efficiency are necessary. Here, we have designed a DSSC with a double-layer structure, in which the top layer consists of a mixture of TiO 2 -P25 and Cr-doped TiO 2 nanotubes (Cr-TNTs). Based on analyses using photoluminescence spectroscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy, we have demonstrated the effect of Cr-TNTs on the separation of photogenerated electron-hole pairs. A photoconversion efficiency (ɳ) of 11.05% was obtained by using the Cr-doped TiO 2 material as compared to 9.05% for the un-doped TiO 2 nanotubes. [ABSTRACT FROM AUTHOR]

A composite photocatalyst, AgBr-BaMoO 4 was fabricated by two step method; microwave hydrothermal and precipitation-deposition. The as prepared photocatalyst samples were characterized by various techniques. The facet coupling was seen between the (204) plane of BaMoO 4 and (200)/(222) planes of AgBr on the basis of XRD/HRTEM analysis. The pharmaceutical pollutant, sulfamethoxazole was adopted to investigate the photocatalytic performances of samples under UV–vis irradiation. The AgBr-BaMoO 4 composite degraded the aqueous sulfamethoxazole drug in UV–vis light about 64% within 75 min, which was attributed to efficient separation of photogenerated electron–hole pairs across the interface between Ag/AgBr and BaMoO 4 . The multi-electron induced oxygen reduced reaction (ORR) was observed. The radical trapping experiment indicates that OH • has major role for sulfamethoxazole degradation. The four successive photodegradation of sulfamethoxazole in UV–vis light indicates the stability of composite photocatalyst. Furthermore, the three different degradation pathways were designed on the basis of retention time and molecular masses of 18 degraded organic fragments that was confirmed by high-performance liquid chromatography photodiode array (HPLC-PDA) and high resolution-quadruple time of flight electrospray ionization mass spectroscopy (HR-QTOF ESI/MS) techniques. The total organic carbon (TOC) analysis suggested the mineralization of SMZ by composite photocatalyst. This study not only demonstrates the enhancement of photocatalytic performance of wide band gap semiconductor by making composite with narrow band gap semiconductor but also detail degradation pathways and mechanisms of sulfamethoxazole. [ABSTRACT FROM AUTHOR]

A novel strategy for fabrication of visible light driven AgBr-α-NiMoO 4 composite photocatalyst has been developed, including microwave hydrothermal and precipitation-deposition method. The fabrication of heterojunction photocatalyst was proved by XRD, FESEM mapping, HRTEM, SAED, EDS, and XPS techniques. The composite photocatalyst degraded naproxen drug around 84% within 20 min under visible light irradiation. The active species trapping experiment confirmed that OH , O 2 − , and h + play a crucial role for naproxen degradation. Due to efficient charge separation, well matched energy band of AgBr and α-NiMoO 4 as well as surface plasmon resonance of silver particles, the composite revealed the high photocatalytic performance with excellent stability up to fifth cycle. In addition, the composite is photochemical stable. Furthermore, the five degradation pathways were proposed on the basis of retention time and theoretical/observed molecular masses of 19 degraded organic fragments that was confirmed by high-performance liquid chromatography-photodiode array (HPLC-PDA) and high resolution-quadruple time of flight electrospray ionization mass spectroscopy (HR-QTOF ESI/MS) techniques. The different reactions (methylation, demethylation, decarboxylation, hydroxylation, oxidation, and coupling) were observed during NPX degradation by photocatalyst. TOC (total organic carbon) analysis revealed that naproxen drug was completely mineralized by composite photocatalyst within 100 min. So, this work represents the fabrication of visible light induced novel composite photocatalyst for rapid degradation of pharmaceutical pollutant with detailed mechanism and pathways. [ABSTRACT FROM AUTHOR]

A 3D hierarchical CoWO 4 /Co 3 O 4 structure, with the synergetic effect of diverse materials, large specific surface area and fast transmission of electrons and ions is synthesized by a facile and efficient microwave hydrothermal method. We found that CoWO 4 and 3D CoWO 4 /Co 3 O 4 exhibit four pairs of redox peaks, which were discussed systematically. The hybrid electrode shows excellent specific capacitance of 1728 F g −1 at current density of 2.7 mA cm −2 (1 A g −1 ) with superior rate capability and satisfactory cycling stability (85.9% capacitance preserved after 5000 cycles). The asymmetric supercapacitors assembled with CoWO 4 /Co 3 O 4 and activated carbon exhibit high energy density (57.8 Wh kg −1 ) and power density (6000 W kg −1 at 40.64 Wh kg −1 ), with remarkable cycle life. The above results indicate that the ordered CoWO 4 /Co 3 O 4 nanowire arrays synthesized by this approach would be a promising candidate for practical application of high-performance supercapacitors. [ABSTRACT FROM AUTHOR]

Zirconium carbide (ZrC) whiskers were successfully synthesized by a combination of microwave hydrothermal (MH) and carbothermal reduction. The precursors of ZrC whiskers were produced by MH, subsequently carbothermally reduced to ZrC whiskers at 1100–1600 °C in an Ar atmosphere. Effects of the reduction temperature and precursors with various carbon/zirconium (C/Zr) molar ratios on the synthesis of ZrC whiskers were investigated. The results showed that the carbothermal reduction occurred at 1100 °C, and terminated at a relatively low temperature (1400 °C). When the reduction temperature was 1500 °C and the C/Zr molar ratio was 5:1, the ZrC whiskers with the largest aspect ratio and the most uniform distribution were produced. The whiskers exhibited the diameters of 0.1–2 µm and the lengths of 5–30 µm. The synthesized ZrC whiskers with a single crystalline phase displayed cylindrical and pagoda-like morphologies. The growth of ZrC whiskers was considered to be governed by the Ostwald ripening and S-L-S mechanism. [ABSTRACT FROM AUTHOR]