Ultrasonic assisted synthesis of Ni3(VO4)2-reduced graphene oxide nanocomposite for potential use in electrochemical energy storage

In the present study, Ni₃(VO₄)₂-reduced graphene oxide (NV/RGO) nanocomposite was synthesized for energy storage purpose. To this end, a mixture containing RGO nanosheets, Ni (CH₃COOH)₂ and Na₃VO₄ mixture was prepared under probe-type ultrasonic irradiation with frequency of 20 KHz and the optimized power of 100 W. The Raman and energy-dispersive X-ray spectroscopies confirmed the presence of RGO nanosheets, nickel and vanadium elements in the NV/RGO, respectively. In addition, field emission-scanning electron microscopy (FESEM) data showed the formation of the NV nanoparticles on the RGO nanosheets. NV/RGO nanocomposite was pasted on nickel foam (NF) and its performance was investigated in energy storage using a three-electrode cell containing 6 M KOH. In cyclic voltammogram of NV/RGO/NF, redox peaks for Ni (II)/Ni (III) with intensities higher than that for NV/NF were observed which confirms the synergistic effect of RGO on the performance of NV. Chronopotentiometry data revealed that the NV/RGO/NF electrode exhibits high capacity of 117.22 mA h g⁻¹ at 2 A g⁻¹. Electrochemical impedance spectroscopy also demonstrated an improvement in the electrical conductivity and electrochemical behavior of NV/RGO/NF nanocomposite compared to the RGO/NF and NV/NF. Furthermore, NV/RGO/NF electrode reserved about 88% of its initial capacity after 1000th potential cycle at 50 mV s⁻¹. Overall, the results of our study suggest that the NV/RGO nanocomposite prepared in the presence of ultrasonic irradiation might be regarded as a suitable active material for energy storage systems.     

Sonochemical synthesized BaMoO4/ZnO nanocomposites as electrode materials: A comparative study on GO and GQD employed in hydrogen storage

Due to poor rate proficiency and electrochemical capacity of transition metal oxides, production electrode materials as operative way to develop the electrochemical performance is a crucial strategy to make sure the great electroactive sites and fast electron/ion diffusion route. In order to solve this problem, carbon-based nanocomposites as conductive substrates are applied. The nanostructured BaMoO₄/ZnO was produced by sonochemical method in the presence of tween 20 as stabilizing agent. Effect of graphene quantum dots (GQDs) and graphene oxide (GO) for developing hydrogen capacity of BaMoO₄/ZnO was studied by providing representative composites of BaMoO₄/ZnO-GQDs and BaMoO₄/ZnO-GO. For this purpose, GQDs was synthesized using green source of Spiraea crenata and the GO provided by commercial company. The structural analysis shows preparation of scales-like morphology of BaMoO₄/ZnO without any impurities through SEM, TEM, XRD, EDS and FT-IR characterization data. Also, the specific surface area for BaMoO₄/ZnO-GQDs (11 m²/g) and BaMoO₄/ZnO-GO (124 m²/g) nanocomposites increased by comparing to BaMoO₄/ZnO (9.1 m²/g). The resultant nanocomposites used as new active compounds for applying in hydrogen storage strategies using cyclic voltammetry and chronopotentiometry tests. Comprehensively, the hydrogen capacitance after 15 cycles was demonstrated on the nanostructured BaMoO₄/ZnO about 129 mAhg⁻¹. It demanded the maximum capacitance for BaMoO₄/ZnO-GQDs and BaMoO₄/ZnO-GO nanocomposites were 284 and 213 mAhg⁻¹ respectively, which was higher than the initial nanostructured BaMoO₄/ZnO. It was exposed from the carbon based structured that; the endorsed electrochemical hydrogen storage (EHS) performance is ascribed to the reaction of the redox pair of Mo⁶⁺ /Mo⁵⁺ at the active sites throughout the EHS procedure. This study delivers a novel plan and potential sorption electrode materials to progress the intrinsic action of conductive compounds.     

Solution-based colloidal synthesis of hybrid P3HT: Ternary CuInSe2 nanocomposites using a novel combination of capping agents for low-cost photovoltaics

In this work, ternary CuInSe₂ (CISe) chalcopyrite nanocrystallites efficiently passivated by a novel combination of capping agents viz: aniline and 1-octadecene during chemical route synthesis were dispersed in conducting polymer matrix poly(3-hexylthiophene) (P3HT). By varying the composition and concentration of the ligands, the properties of the resulting CISe nanocrystallites and its corresponding polymer nanocomposites thus could be tailored. The structural, morphological and optical studies accomplished by various complimentary techniques viz. Transmission Electron Microscopy (TEM), Contact angle, Photoluminescence (PL) and Raman have enabled us to compare the different hybrid organic (polymer)-inorganic nanocomposites. On the basis of aniline–octadecene equilibrium phase diagram, the polydispersity of the CISe nanocrystals could be tuned by using controlled variations in the reaction conditions of nucleation and growth such as composition of the solvent and temperature. To the best of author’s knowledge, the beneficial effects of both the capping agents; aniline and octadecene contributing well in tandem in the development of large-sized (100–125 nm) high quality, sterically- and photo-oxidative stable polycrystalline CISe and its corresponding polymer (P3HT):CISe composites with enhanced charge transfer efficiency has been reported for the first time. The low-cost synthesis and ease of preparation renders this method of great potential for its possible application in low-cost hybrid organic–inorganic photovoltaics.     

Surface morphology and electrochemical characterization of electrodeposited Ni-Mo nanocomposites as cathodes for hydrogen evolution

In this work, we study the influences of current density on surface morphology and electrochemical characterization of electrodeposited Ni–Mo. The Ni–Mo composite coatings are deposited on pretreated copper substrates by electrolytic deposition. The Ni–Mo solution is taken from nickel sulfate fluid and ammonium heptamolybdate with 10 g/l. The Ni–Mo composite coatings are deposited at a temperature of 303 K with an applied current density of j dep= 10 A/dm2–30 A/dm2.We find that the corrosion resistance is improved by incorporating Mo particles into Ni matrix in 0.6-M Na Cl solution. From the potentiodynamic polarization curve of electrodeposited Ni–Mo it is confirmed that the corrosion resistance decreases with increasing applied current density. The x-ray diffraction(XRD) analyses of Ni–Mo coatings indicate three phases of Mo Ni4, Mo1.24Ni0.76, and Ni3 Mo phases crystallites of nickel and molybdenum. The scanning electronic microscopy(SEM) tests indicate that Ni–Mo coatings present cracks and pores.     

A novel sodium iodide and ammonium molybdate co-catalytic system for the efficient synthesis of 2-benzimidazoles using hydrogen peroxide under ultrasound irradiation

The reaction of aldehydes and o-phenylenediamine for the preparation of 2-benzimidazoles has been studied using hydrogen peroxide as an oxidant under ultrasound irradiation at room temperature in this paper. The combination of substoichiometric sodium iodide and ammonium molybdate as co-catalysts, together with using small amounts of hydrogen peroxide, makes this transformation very efficient and attractive under ultrasound. Thus, a mild, green and efficient method is established to carry out this reaction in high yield.     

Ultrasonic irradiation preparation of graphitic-C3N4/polyaniline nanocomposites as counter electrodes for dye-sensitized solar cells

In this research, polyaniline/graphitic carbon nitride (PANI/g-C₃N₄) nanocomposites were synthesized via in-situ electrochemical polymerization of aniline monomer whit different number of cyclic voltammetry scans (10, 20 and 30 cycles) after electrode surface pre-preparation using a potential shock under ultrasonic irradiation. PANI/g-C₃N₄ nanocomposites with two values of g-C₃N₄ (0.010 wt% and 0.015 wt%) were deposited on the surface of the transparent conducting film (FTO glass) by immersing FTO into the aniline solution and g-C₃N₄ during the electro-polymerization. The resulting PANI/g-C₃N₄ films were characterized by Fourier transformed infra-red (FTIR), power X-ray diffraction (PXRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) techniques. The prepared electrodes were applied as counter electrode in dye-sensitized solar cells. Among them, the prepared electrode with 10 cycles and 0.01 wt% g-C₃N₄ showed the best efficiency. These hybrids show good catalytic activity in elevating tri-iodide reduction and due to the synergistic effect of PANI and g-C₃N₄, PANI/g-C₃N₄ nanocomposite electrode shows power conversion efficiency about 1.8%.     

Facile synthesis of multifunctional Ag/Fe3O4-CS nanocomposites for antibacterial and hyperthermic applications

Nanocomposites containing two or more functional constituents are attractive candidates for advanced nanomaterials. In this study, multifunctional Ag/Fe₃O₄-CS nanocomposites were successfully prepared, using chitosan as a stabilizing and cross-linking agent. The as-synthesized nanocomposites were characterized by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDS), UV–visible spectrophotometer (UV–Vis) and vibrating sample magnetometer (VSM). The results demonstrated that Ag/Fe₃O₄-CS composite nanoparticles (NPs) were composed of parent components, Fe₃O₄ and Ag NPs, which were uniformly dispersed in the chitosan matrix. The hybrid NPs exhibited strong antibacterial property against Pseudomonas aeruginosa. With high magnetization value (67 emu/g), the synthesized Ag/Fe₃O₄-CS composite can be easily separated or recycled in potential biomedical applications. Furthermore, the results showed that the multicomponent hybrid nanostructures appeared to be the promising material for local hyperthermia, which can be used as thermoseeds for localized hyperthermia treatment of cancers.     

Ultrasonic-assisted fabrication and characterization of PVC-SiO2 nanocomposites having bovine serum albumin as a bio coupling agent

In this work, SiO₂ nanoparticles (NPs) were modified with bovine serum albumin (BSA) under ultrasound irradiations as a green and fast route to achieve their good dispersion. Subsequently, different weight percentages of the modified NPs (3, 6, and 9 wt%) were incorporated in poly(vinyl chloride) (PVC) as the matrix. Thermogravimetric analysis of the SiO₂-BSA NPs indicated that 12 wt% of the modifier was loaded on the surface of SiO₂ NPs. Encapsulation of the SiO₂-BSA resulted in a meaningful improvement in the optical, mechanical and thermal characteristics of the prepared PVC nanocomposites (NCs). X-ray diffraction (XRD) patterns for the PVC/SiO₂-BSA NCs showed a crystalline behavior for the NC with 6 wt% of the SiO₂-BSA originated from the phosphate buffer on the NPs. Water contact angle of the PVC/SiO₂-BSA NCs showed that the hydrophilicity enhanced with increasing of the NPs contents.     

Ultrasonic assisted synthesis of Bikitaite zeolite: A potential material for hydrogen storage application

Li containing Bikitaite zeolite has been synthesized by an ultrasound-assisted method and used as a potential material for hydrogen storage application. The Sonication energy was varied from 150 W to 250 W and irradiation time from 3 h to 6 h. The Bikitaite nanoparticles were characterized by X-ray diffraction (XRD), infrared (IR) spectral analysis, and field-emission scanning electron microscopy (FESEM) thermo-gravimetrical analysis and differential thermal analysis (TGA, DTA). XRD and IR results showed that phase pure, nano crystalline Bikitaite zeolites were started forming after 3 h irradiation and 72 h of aging with a sonication energy of 150 W and nano crystalline Bikitaite zeolite with prominent peaks were obtained after 6 h irradiation of 250 W sonic energy. The Brunauer–Emmett–Teller (BET) surface area of the powder by N₂ adsorption–desorption measurements was found to be 209 m²/g. The TEM micrograph and elemental analysis showed that desired atomic ratio of the zeolite was obtained after 6 h irradiation. For comparison, sonochemical method, followed by the hydrothermal method, with same initial sol composition was studied. The effect of ultrasonic energy and irradiation time showed that with increasing sonication energy, and sonication time phase formation was almost completed. The FESEM images revealed that 50 nm zeolite crystals were formed at room temperature. However, agglomerated particles having woollen ball like structure was obtained by sonochemical method followed by hydrothermal treatment at 100 °C for 24 h. The hydrogen adsorption capacity of Bikitaite zeolite with different Li content, has been investigated. Experimental results indicated that the hydrogen adsorption capacities were dominantly related to their surface areas as well as total pore volume of the zeolite. The hydrogen adsorption capacity of 143.2 c.c/g was obtained at 77 K and ambient pressure of (0.11 MPa) for the Bikitaite zeolite with 100% Li, which was higher than the reported values for other zeolites. To the best of our knowledge, there is no report on the synthesis of a Bikitaite zeolite by sonochemical method for H₂ storage.     

Sonochemical synthesis and fabrication of neodymium sesquioxide entrapped with graphene oxide based hierarchical nanocomposite for highly sensitive electrochemical sensor of anti-cancer (raloxifene) drug

The ultrasound-assisted synthesis of a novel neodymium sesquioxide nanoparticles (Nd₂O₅ NPs) decorated graphene oxide (GO) nanocomposite under ultrasonic probe (Ultrasonic processor model-PR 1000; frequency-30 kHz; power of 100 W/cm²) has been reported. After then, SEM, TEM, XRD, EDX and electrochemical impedance spectroscopy characterized was analyzed using Nd₂O₅ NPs@GO nanomaterial. Furthermore, the nanomaterial modified GCE (glassy carbon electrode) shows excellent electrochemical sensing performance towards anti-cancer drug. Raloxifene is one of the important anti-cancer drug. Moreover, the fabricated electrochemical sensor has showed a wide linear range for raloxifene between 0.03 and 472.5 µM and nanomolar detection limit (18.43 nM). In addition, the Nd₂O₅ NPs@GO modified sensor has been applied to the determination of raloxifene in human blood and urine samples.     

Ultrasonic accelerated coupling reaction using magnetically recyclable bis (propyl molononitril) Ni complex nanocatalyst: A novel,green and efficient synthesis of biphenyl derivatives

A novel, green and rapid sonochemical research to preparation of the biphenyls was carried out through the coupling reaction between various aryl halides and phenylboronic acid by using bis(propyl malononitrile) Ni (0) complex (NiFe₂O₄@SiO₂-BPMN-Ni) as an efficient nano catalyst. The catalyst can be recycled via an external magnet and reused several times without considerable loss of its catalytic activity. Compare to the previous works, this procedure has advantages such as easy workup, high yields of products, environmentally benign and short reaction times. The novel nickel catalyst prepared and characterized by FT-IR, XRD, SEM, EDX, TGA and VSM techniques.     

Bifunctional Au-nanorod@Fe3O4 nanocomposites: synthesis, characterization, and their use as bioprobes

Membrane gas separation technology has been rapidly growing for industrial applications such as air separation, carbon dioxide (CO₂) separation from natural gas production, hydrogen separation, etc. Needs for CO₂ separation are increasing as carbon capture technology has been recognized as an essential part when combating the global warming issue. Membrane gas separation technology deals with mass transport phenomena through the membrane engineered on a sub-nanoscale controlling transport properties of small gas molecules such as CO₂, N₂, O₂, H₂, etc. In this review, we will report on the recent developments in capture technologies utilizing various membranes including nano-engineered thermally rearranged (TR) polymers. TR polymer membranes show high gas permeability as well as good separation properties, especially in CO₂ separation processes such as from post-combustion flue gas and natural gas sweetening.     

The effect of different parameters under ultrasound irradiation for synthesis of new nanostructured Fe3O4@bio-MOF as an efficient anti-leishmanial in vitro and in vivo conditions

In this work, a magnetic bio-metal–organic framework (MBMOF) nanocomposite with porous-layer open morphology is synthesized through a simple sonochemical approach and its effects on Leishmania major (MRHO/IR/75/ER) under both in vitro and in vivo conditions are investigated. The effects of sonication time, initial concentration of reagents and sonication power on size and morphology of MBMOF nanocomposites have been investigated and optimized. A comparison was then made between the structural information of the nanostructures and that of the bio-metal–organic framework crystals. Using the powder X-ray diffraction (PXRD), field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), energy dispersive analysis of X-ray (EDAX), vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA), and Brunauer-Emmet-Teller (BET) techniques, the prepared MBMOF nanocomposites were characterized. The mean numbers of promastigotes (cell/ml) in different MBMOF concentrations (3.12, 6.25, 12.5, 25, 50, 100, 200 and 400 µg mL⁻¹) were determined by direct counting after 24, 48 and 72 h. Using MTT assays, the cytotoxic impacts of the MBMOF nanocomposites on promastigotes, intracellular amastigotes, and J774 macrophages were estimated. In order to investigate their therapeutic effects, the prepared MBMOF nanocomposites (25 and 12.5 µg mL⁻¹) were used as ointment three times a week to treat Leishmania major in BALB/c mice. The lesion size and weight of mice were assessed before and during the treatment. The parasitic loads were measured in spleen and liver through the culture. After 72 h, the INF-γ and IL-4 cytokines levels in the supernatant of the spleen culture were measured. To the best of the authors’ knowledge, this study is the first to attempt to synthesize the bio-MOFs through an in-situ sonosynthesis route under ultrasound irradiation and examine their cytotoxicity effects on Leishmania major under in vitro and in vivo conditions.     

Ag3PO4/rectorite nanocomposites: Ultrasound-assisted preparation,characterization and enhancement of stability and visible-light photocatalytic activity

To overcome the drawback of low stable brought by the transformation of Ag⁺ into Ag, a highly efficient and stable photocatalyst Ag₃PO₄/rectorite composite was successfully synthesized by ultrasound-assisted precipitation method. The as-prepared samples were characterized by field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, N₂ adsorption-desorption, room-temperature photoluminescence spectra, Fourier transform infrared spectrum measurements and UV–vis diffuse reflectance spectra. The absorption edges of the Ag₃PO₄/rectorite display a noticeable shift to the visible light region as compared to that of the Ag₃PO₄. Compared with bare Ag₃PO₄, the Ag₃PO₄/rectorite composite by ultrasound-assisted precipitation process exhibits significantly enhanced photocatalytic activity and stable for methyl orange (MO) degradation under visible light irradiation. The improved activity of the Ag₃PO₄/rectorite photocatalyst could be attributed to the expanded visible light absorption, the enhanced interfacial charge transfer and the inhibited recombination of electron-hole pairs. Therefore, the facile ultrasound-assisted preparation process provides some insight into the application of Ag₃PO₄/rectorite nanocomposites in photocatalytic degradation of organic pollutants.     

Simple sonochemical synthesis of Ho2O3-SiO2 nanocomposites as an effective photocatalyst for degradation and removal of organic contaminant

In this work, highly photocatalytically active Ho₂O₃-SiO₂ nanocomposites have been designed and applied for decomposition of methylene blue pollutant. Ho₂O₃-SiO₂ nanocomposites have been produced by new, quick and facile sonochemical process with the aid of tetramethylethylenediamine as a novel basic agent for the first time. The effect of the kind of basic agent, ultrasonic time and dosage of Ho source on the grain size, photocatalytic behavior and shape of the Ho₂O₃-SiO₂ nanocomposites have been evaluated for optimization the production condition. FESEM, EDX, FT-IR, DRS, XRD and TEM have been applied to characterize the as-produced Ho₂O₃-SiO₂ nanocomposites. Use of the as-produced Ho₂O₃-SiO₂ nanocomposites as photocatalyst via destruction of methylene blue pollutant under UV illumination has been compared. It was observed that SiO₂ has notable impact on catalytic activity of holmium oxide photocatalyst for destruction. Introducing of SiO₂ to holmium oxide can enhance destruction efficiency of holmium oxide to methylene blue pollutant under ultraviolet light.     

Ultrasound-assisted synthesis of graphene@MXene hybrid: A novel and promising material for electrochemical sensing

To date, multiple graphene@MXene hybrids have been reported via various synthesis approaches, but almost all the graphene@MXene hybrids inevitably used the reduced graphene oxide that prepared by chemical oxidation/reduction method, which generally involved the complex and dangerous operation procedure, and the highly toxic chemical reagent. How to prepare graphene@MXene hybrid through a simple, safe and eco-friendly synthetic route is highly desired. Compared with traditional synthesis technology, ultrasound synthesis strategy displays the merits of simplicity, low cost and environment protection. Herein, MXene (Ti₃C₂T_x) nanoflakes coupled with graphene nanosheets (graphene@MXene) were prepared in N-methylpyrrolidone (NMP) by simple ultrasound-assisted liquid-phase exfoliation method for the first time. Besides, the effect of types of solvent with different viscocity, sonication temperature and sonication duration time on the property of graphene@MXene hybrids were systematacially investigated. It is found the liquid-phase exfoliated graphene owned excellent electron transfer ability and the MXene (Ti₃C₂T_x) nanoflakes possessed outstanding adsorption property, the as-synthesized graphene@MXene hybrid exhibited significant signal synergistic enhancement effect toward the oxidation of hazardous veterinary drug residue compound (chlorpromazine) and food additives (rhodamine B). Based on this, a novel and sensitive electrochemical sensor was fabricated, the linear detection ranges were 5 nM to 0.5 μM for chlorpromazine with sensitivity of 1090 µA μM⁻¹ cm⁻², and 10 nM to 2.5 μM for rhodamine B with sensitivity of 440 and 102.14 µA μM⁻¹ cm⁻². Besides, the detection limits were evaluated to be as low as 1.25 nM and 2.45 nM for chlorpromazine and rhodamine B, respectively.     

Ultrasound-promoted green approach for the synthesis of sulfonamides using natural,stable and reusable Natrolite nanozeolite catalyst at room temperature

Natural Natrolite nanozeolite has been investigated as an efficient and reusable catalyst for the N-sulfonylation of amines under ultrasound irradiation at room temperature. Compared with traditional methods, the significant advantages for method are green solvent, milder and cleaner conditions, higher purity and yields, shorter reaction time, easier work-up procedure and the lower generation of waste or pollutions. The catalyst can be recovered and reused several times without significant loss of its catalytic activity.     

Sonochemically preparation and characterization of bimetallic Ni-Co/Al2O3-ZrO2 nanocatalyst: Effects of ultrasound irradiation time and power on catalytic properties and activity in dry reforming of CH4

The catalytic performance of nanostructured Ni-Co/Al₂O₃-ZrO₂ catalysts, prepared by ultrasound-assisted impregnation method was examined in the dry reforming of methane. The effect of irradiation power and irradiation time have been studied by changing time (0, 20, 80 min) and power of the sonication (30, 60, 90 W) during the synthesis which resulted in different physiochemical properties of the nanocatalyst. The nanocatalysts were characterized by XRD, FESEM, PSD, EDX, TEM, TPR-H₂, BET, FTIR and TG analyses. Based on the characterization results, ultrasound treatment endowed the sample with more uniform and smaller nanoparticles; higher surface area, stronger metal-support interaction and more homogenous dispersion. Moreover, the analyses exhibited smaller particles with higher surface area and less population of particle aggregates at longer and highly irradiated nanocatalysts. The nanocatalyst irradiated at 90 W for 80 min (the longest irradiation time and the most intense power) showed a uniform morphology and a very narrow particles size distribution. More than 65% of particles of this nanocatalyst were in the range of 10–30 nm. Activity tests demonstrated that employing ultrasound irradiation during impregnation improves feed conversion and products yield, reaching values close to equilibrium. Among sonicated nanocatalysts, with increasing power and time of irradiation, the nanocatalyst represents higher activity. The superior performance amongst the various bimetallic catalysts tested was observed over the catalyst with 90 W and 80 min ultrasonic irradiation which is stable in 24 h time on stream test. The excellent anti-coking performance of this bimetallic catalyst, confirmed by TG and FESEM analyses of spent catalyst, is closely related to the promoting effect of sonication on the metal-support interaction, Ni dispersion and particle size; and probably, the synergy between metallic species.