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.

Decoration of green synthesized S, N-GQDs and CoFe2O4 on halloysite nanoclay as natural substrate for electrochemical hydrogen storage application.

Halloysite nanotubes (HNTs) with high active sites are used as natural layered mineral supports. Sulfur- and nitrogen-co doped graphene quantum dots (S, N-GQDs) as conductive additive and CoFe2O4 as the electrocatalyst was decorated on a HNT support to design an effective and environmentally friendly active material. Herein, an eco-friendly CoFe2O4/S, N-GQDs/HNTs nanocomposite is fabricated via a green hydrothermal method to equip developed hydrogen storage sites and to allow for quick charge transportation for hydrogen storage utilization. The hydrogen storage capacity of pure HNTs was 300 mAhg-1 at a current density of 1 mA after 20 cycles, while that of S, N-GQD-coated HNTs (S, N-GQDs/HNTs) was 466 mAhg-1 under identical conditions. It was also conceivable to increase the hydrogen sorption ability through the spillover procedure by interlinking CoFe2O4 in the halloysite nanoclay. The hydrogen storage capacity of the CoFe2O4/HNTs was 450 mAhg-1, while that of the representative designed nanocomposites of CoFe2O4/S, N-GQDs/HNTs was 600 mAhg-1. The halloysite nano clay and treated halloysite show potential as electrode materials for electrochemical energy storage in alkaline media; in particular, ternary CoFe2O4/S, N-GQD/HNT nanocomposites prove developed hydrogen sorption performance in terms of presence of conductive additive, physisorption, and spillover mechanisms.

Sonochemical synthesis, characterization and application of PrVO4 nanostructures as an effective photocatalyst for discoloration of organic dye contaminants in wastewater.

In the current research, various conventional chemical preparation methods without ultrasound aid (precipitation, microwave, and hydrothermal) were compared with sonochemical procedure and were performed for providing of PrVO4 nanostructures using Schiff-base ligands. The small size products with monodisperse particles (~39 nm) optimized by sonochemical fabrication method and using H2 acacpn ligand via ultrasonic probe with power of 60 W and frequency of 18 KHz. The produced PrVO4 nanostructures applied for degradation of diverse organic dyes through the photocatalytic process. Dye types, pH adjusting of dye, dosage of catalyst, synthesis method of nanoparticles and light source as impressive factors inquired for dye removal ability. The outcomes presented the removal efficiency of Eriochorom Black T in optimal conditions of pH = 11 and the catalysts amounts of PrVO4 were adjusted to be 0.05 g. The PrVO4 photocatalyst shows high removal efficiency (ca 86.92 and 89.61%) after 90 min of operation under UV light. The best-obtained framework confirmed the basic study to compare different method in order to acquire suitable catalyst materials. The simple, fast and economic strategy for synthesis PrVO4 with high photodegradation efficiency is sonochemical method against other ways, and it could be extended to the most efficient catalyst materials for water treatment. Consequently, the PrVO4 may suggestion a hopeful avenue for designing the novel generation, low-cost and outstanding potential photocatalyst materials for water treatment.

CdSnO3-graphene nanocomposites: Ultrasonic synthesis using glucose as capping agent and characterization for electrochemical hydrogen storage.

Nanoscale cadmium stannate (CdSnO3) structures were productively synthesized via a facile and rapid sonochemical route using an eco-friendly capping agent of glucose. In order to optimize the size and structure of products, the various effective factors were inquired such as ultrasound waves, calcination temperature and solvent. The all samples were synthesized under ultrasonic probe for 30 min and different power (frequency) of 80 (24 KHz), 60 (18 KHz) and 40 W (12 KHz). The properties and characteristics of as-fabricated samples were examined by proficient techniques to identification the purity, structure, shape, optical, electrical and surface features. The ability of CdSnO3 nanostructures and representative graphene based nanocomposites as potential hydrogen storage materials was considered by electrochemical methods. According to the obtained results, the CdSnO3/graphene nanocomposites demonstrated higher hydrogen storage capacity than pristine CdSnO3 nanostructures.

Ultrasound-accelerated synthesis of uniform DyVO4 nanoparticles as high activity visible-light-driven photocatalyst.

In order to obtain a highly efficient photocatalyst for water treatment, the sonochemical procedure applied to fabrication of excellent DyVO4 nanoparticles. A comparative study between two different synthesis routes (precipitation and sonochemical) was investigated in this work. Also, the influence of anionic, cationic and nonionic surfactant was studied on the formation of uniform particles. Further, the photocatalytic performance over the DyVO4 nanoparticles was studied under visible light by modifying the operational variables. Investigation of the photocatalytic mechanism process was conducted using hole scavengers for capturing reactive species. It was found that the DyVO4 nanoparticles sonochemically (a ultrasound probe with power of 60 W (18 KHz)) synthesized in presence of CTAB as an optimum condition, are uniform with average size of ~24 nm. The results showed that DyVO4 could remove near 88% of erythrosine, under the optimum condition of 0.05 g catalyst dosage and at initial pH 4. The DyVO4 maintained relatively high stability and reusability removal for erythrosine after five repeated cycles. The results could provide effective functional materials for elimination of chemical contaminants from wastewater through the photocatalytic process.

Utilizing of neodymium vanadate nanoparticles as an efficient catalyst to boost the photocatalytic water purification.

Neodymium Vanadate (NdVO4) nanostructures were successfully synthesized via a modified solid state method in the presence of ligand. These nanoparticles were further used as a photocatalyst. Primarily the best structural formations and smallest crystallite sizes of the systems were identified and optimized by changing the calcination time, calcination temperature and molar ratio of the ligand. The cationic (Methyl Violet (MV)), and anionic (Eosin Y (EY) and Eriochrome Black T (EBT)) dyes were used as a model to evaluate the photoactivity under UV-Vis irradiation. Several operational factors were examined to improve the photocatalytic efficiency include type of dye, type of light source, pH and dye concentration. As a result, the best efficiency in 5 ppm Eriochorome Black T at pH = 11 was achieved in the presence of 0.05 g NdVO4 nanocatalysts.

Application of ultrasound-aided method for the synthesis of NdVO4 nano-photocatalyst and investigation of eliminate dye in contaminant water.

This paper presents a new approach to preparation of neodymium vanadate nanostructures via facile sonochemical route. Several parameters were compared to reach optimum size and uniformity of as-made samples. These factors include sonication time, sonication power, solvent and using ethylenediamine as alkaline and capping agent, for the first time. Neodymium vanadate nano-photocatalyst applied in decolouration of dye as organic contaminant. Effect of type of dye, type of irradiation source, pH and catalyst loading was described on improving efficiency of catalyst function. Numerous techniques were specified in order to determine purity, morphology and optical properties of products consist XRD, FT-IR, EDX, SEM, TEM and DRS.

Enhanced photodegradation of dye in waste water using iron vanadate nanocomposite; ultrasound-assisted preparation and characterization.

The paper proposes a new approach to Schiff-base ligand assisted sonochemical synthesis of iron vanadate. In this disquisition, we tried to comparing various factors and reaction condition on morphology, size and uniformity of as-obtained samples. Some parameters including Schiff-base capping agent (Bis(acetylacetone) ethylenediamine=H2acacen), electrolyte (NH4F), solvent and reaction time were investigated to reach optimum condition. XRD, FT-IR, EDS, SEM and TEM were used in order to determine purity and structural morphology of as-synthesized products. Also, we explore the possibility of coupling vanadium pantaoxide into iron vanadate that improves optical properties and photocatalytic activity. With this in mind, FeVO4/V2O5 nanocomposite was prepared via in-situ ultrasound-assisted procedure by using NH4F in one step. Influence of different parameters such as type of dye (Rhodamine B=Rh B, Phenol red=Ph R and Methyl violet=MV) and light source (Ultraviolet and visible) on photocatalytic ability of samples were studied.

Novel chemical synthesis and characterization of copper pyrovanadate nanoparticles and its influence on the flame retardancy of polymeric nanocomposites.

In this work, copper pyrovanadate (Cu3V2O7(OH)2(H2O)2) nanoparticles have been synthesized by a simple and rapid chemical precipitation method. Different copper-organic complexes were used to control the size and morphology of products. The morphology and structure of the as-synthesized products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectrum, electron dispersive X-ray spectroscopy (EDX), thermal gravimetric analysis (TGA), differential thermal analysis (DTA) and photoluminescence (PL) spectroscopy. The influence of copper pyrovanadate nanostructures on the flame retardancy of the polystyrene, poly vinyl alcohol and cellulose acetate was studied. Dispersed nanoparticles play the role of a magnetic barrier layer, which slows down product volatilization and prevents the flame and oxygen from the sample during decomposition of the polymer. Cu3V2O7(OH)2(H2O)2 is converted to Cu3V2O8 with an endothermic reaction which simultaneously releases water and decrease the temperature of the flame region.