Ammonium Heptamolybdate Tetrahydrate Research Articles

Facile synthesis route for bulk production of complex fullerene-like MoS2 nanostructures with enhanced tribological properties.

Molybdenum-based nanoparticles are often used as oil additives to enhance a material's tribological performance. Here, we present a highly efficient synthetic route for the bulk production of two types of MoS2 nanostructures: multi-wall nanotubes and fullerene-like nanostructures. The presented two-step synthesis involves the transformation of ammonium heptamolybdate tetrahydrate and aniline into precursor nanowires, which are later transformed into MoS2 through heating in a H2S, H2 , and argon atmosphere to approximately 800°C. Depending on the heating rate, we successfully grew MoS2 layered compounds in various shapes and sizes. The resulting structures and compositions were characterised by X-ray powder diffraction, Raman spectroscopy, energy-dispersive X-ray spectroscopy, and electron microscopy. To assess the application potential of these MoS2 compounds, they were dispersed in polyalphaolefin (PAO 6) oil. Improved tribological properties were observed compared to typically used transition metal dichalcogenides.

Investigation of rare earth metal ions (Sm and Er) doped CoMoO4 polymorphs for photocatalytic dye degradation

Cobalt molybdate (CoMoO4) and its rare earth doped variants have emerged as promising photocatalysts for degrading dye pollutants in wastewater. The photocatalysts were prepared using a modified sol-gel method, employing ammonium heptamolybdate tetrahydrate and cobalt (II) nitrate hexahydrate as precursors. The incorporation of samarium and erbium as a dopant was hypothesized to improve the photocatalytic activity of CoMoO4 by altering its band structure and creating defect sites for improved dye adsorption and degradation. The structural and optical properties of the synthesized photocatalysts were characterized using various techniques. The photocatalytic performance of CoMoO4, Sm:CoMoO4 and Er:CoMoO4 was evaluated by monitoring the degradation of MB dye under light irradiation. The results reveal that Sm:CoMoO4 and Er:CoMoO4 catalysts achieve a degradation efficiencies of 99 % and 97 %, respectively, highlighting the potential of rare earth-doped CoMoO4 as an efficient photocatalyst for the remediation of dye contaminated wastewater.

Electrical Study of Changes in Impedance and Internal Parameters of Nano Structures of Molybdenum Disulfide Semiconductor Type (MoS2-2H/3R) with Changes in Temperature

MoS2 nanostructures were prepared using the hydrothermal method by reacting ammonium heptamolybdate tetrahydrate ((NH4)6Mo7O244H2O) with citric acid monohydrate (C6H8O7H2O) in distilled water with the presence of sodium sulfide (Na2S), we have found from the Arenos diagram that the value of the activation energy of (MoS2 -2H/3R) is low and equal to Ea= 0.0505 (e.V). From the atomic force microscope (AFM) images, we found that the size of the surface aggregates of the sample (table - MoS2-2H/3R) ranges between (100-150) n m. From studying the changes in the impedance with different temperatures (T = 15, 30, and 60), we found that impedance is inversely proportional to both the applied frequency and the temperature, and at the frequencies the response corresponding to the temperature reaches a value of (Z = 20 K.Ω, T = 15°C). ) and at temperature (Z = 8.02 K.Ω, T = 30 °C), and at (Z = 17.1 K.Ω, T = 60 °C), It has been shown that the number of electric charge carriers (Nd) increases with increasing temperature. On the contrary, we found a decrease in the number of electronic traps (Ns) and a decrease in the relaxation time τP with increasing temperature.

OBTAINING HUMATE-, NITROGEN AND MOLYBDENUM-CONTAINING LIQUID ORGANOMINERAL FERTILIZERS

The presence of humic substances (HS) and microelements in liquid organomineral fertilizers (LOMF) makes it possible to balance the mineral nutrition of plants and thereby increase the agricultural crops yield. The use of such fertilizers significantly increases the efficiency and reduces the costs of using mineral fertilizers. The aim of this work is to study the patterns of new types LOMF obtaining process, including macro- and microelements and physiologically active humic substances, and its composition and properties. Methods. Chemical analysis, inductively coupled plasma atomic emission spectrometer, infrared spectroscopy. Results and discussion. The processes of synthesis of LOMF through the interaction of sodium humate and ammonium heptamolybdate tetrahydrate were studied. Analysis of obtained results showed the same nature of the composition dependence and properties of the obtained LOMF on time. It was found that increasing the time from 10 to 120 min leads to an increase in the yield of humic acids (HAdaf) to 40.08%, the N content to 4.62% and Mo to 0.17%, the amount of COOH to 1.80 mg-eq/g and OHphen. groups – up to 0.71 mg-eq/g. It has been shown that with an increase in S:L ratio from 0.3:100 to 0.7:100, the HAdaf decreases to 36.97%, and the N and Mo contents increase, respectively, to 6.0 and 0.37%. Conclusion. The regularities of the time influence and S:L ratios on the composition and properties of LOMF samples have been established. It has been shown that an increase in time and S:L ratio contributes to an increase in the content of N and Mo, the carboxyl and phenolic hydroxyl groups. The changes in these parameters have different effects on the HAdaf. The presence of HS, N, Mo, COOH and OHphen groups in the resulting products allows them to be used in agriculture and for restoring soil fertility.

Development of Molybdenum trioxide (MoO3) by spin coating method for photovoltaic application

Molybdenum trioxide, MoO3 , thin films have been deposited on glass substrates by Spin-coating method using ammonium heptamolybdate tetrahydrate ((NH4 )6Mo7O244H2O ) as a single source precursor of Mo and O and. They were subjected to atmospheric heat treatment at different temperatures (200°C, 400°C and 500°C). MoO3 thin films obtained, were characterized using X-ray diffraction techniques (XRD), Scanning Electron Microscopy (SEM), Energy Dispersed Spectroscopy (EDS) and integrating sphere. The XRD patterns of annealed films show the formation of ΜοΟ3 in a polycrystalline phase, formation of MoO3 was also confirmed by EDS. The SEM photographs show that the thin films obtained are in layer-type structure and their grains size increases with increasing of annealing temperatures. The measurement results of integrating sphere show that the MoO3 thin film prepared at 500°C transmit about 72% and reflect about 12% of the visible spectrum.

A Novel Hydro-Thermal Synthesis of Nano-Structured Molybdenum-Iron Intermetallic Alloys at Relatively Low Temperatures

Nano-structured Mo/Fe intermetallics were synthesized from precursors that contained 72/28% and 30/70% molar ratios of Mo/Fe, which were given as precursors A and B, respectively. These precursors were prepared from the co-precipitation of aqueous hot solutions of ammonium heptamolybdate tetrahydrate (AHM) and ferrous oxalate. The dry precipitates were thermally treated using TG-DSC to follow up their behavior during roasting, in an Ar atmosphere of up to 700 °C (10° K/min). The TG profile showed that 32.5% and 55.5% weight losses were measured from the thermal treatment of precursors A and B, respectively. The DSC heat flow profile showed the presence of endothermic peaks at 196.9 and 392.5-400 °C during the thermal decomposition of the AHM and ferrous oxalate, respectively. The exothermic peak that was detected at 427.5 °C was due to the production of nano-sized iron molybdate [Fe2(MoO4)3]. An XRD phase analysis indicated that iron molybdate was the only phase that was identified in precursor A, while iron molybdate and Fe2O3 were produced in precursor B. Compacts were made from the pressing of the nano-sized precursors, which were roasted at 500 °C for 3 h. The roasted compacts were isothermally reduced in H2 at 600-850 °C using microbalance, and the O2 weight loss that resulted from the reduction reactions was continuously recorded as a function of time. The influence of the reduction temperature and precursor composition on the reduction behavior of the precursors was studied and discussed. The partially and completely reduced compacts were examined with X-ray powder diffraction (XRD), a reflected light microscope (RLM), and a scanning electron microscope (SEM-EDS). Depending on the precursor composition, the reduction reactions of the [Fe2(MoO4)3] and Fe2O3 proceeded through the formation of intermediate lower oxides, prior to the production of the MO/Fe intermetallic alloys. Based on the intermediate phases that were identified and characterized at the early, intermediate, and final reduction degrees, chemical reaction equations were given to follow up the formation of the MoFe and MoFe3 intermetallic alloys. The mechanism of the reduction reactions was predicted from the apparent activation energy values (Ea) that were computed at the different reduction degrees. Moreover, mathematical formulations that were derived from the gas-solid reaction model were applied to confirm the reduction mechanisms, which were greatly dependent on the precursor composition and reduction temperature. However, it can be reported that nano-structured MoFe and MoFe3 intermetallic alloys can be successfully fabricated via a gas-solid reaction technique at lower temperatures.

Действие электронного луча на кристаллы и пленки аминиевых и аммониевых солей

The results of studying the action of an electron beam on tetramethylethylenediamine nitrilotriacetate crystals [HMe2NCH2CH2NMe2H]2+[HN(CH2COOH)(CH2COO)2]2–, ammonium heptamolybdate tetrahydrate (NH4)6Mo7O24.4H2O, polymeric trihydrate of zinc nitrilotrimethylenephosphonate (ZnH4L•3H2O)n, lamellar crystals of 2,2'-(ethylenedioxy)di(ethylamine) trifluoroacetate CF3C(O)O‒ +H3N(CH2CH2O)2CH2CH2NH3+ ‒O(O)CCF3 and films of the monoethanolamine salt of ethylenediaminetetraacetic acid [Н3NCH2CH2OH]2+[(OOCCH2)2NCH2CH2N(CH2COOH)2]2– are presented. A Tescan VEGA II electron microscope was used as an exposure tool. The microrelief was examined at magnifications from 500x to 50000x. The survey was carried out at an accelerating voltage of 20 kV and a working distance of 2–8 mm, using detectors of secondary electrons (SE) and backscattered electrons (BSE). A copper-nickel alloy and silicate glass were used as the substrate material for the films. Irradiation of crystals and films was carried out by an electron beam of various powers, forming an area 2020 μm in size. At low power, the area dimensions are strictly 2020 microns, the surface remains relatively flat. An increase in power or an increase in exposure while maintaining power causes an increase in size by 5 to 34 %. The maximum impact causes the formation of defects in the form of cracks, swellings, bubbles, holes, and craters. The elevation of the surface increases with increasing radiation dose.

Method Validation and Uncertainty Estimation for Total Phosphorus Determination in Animal Feed Using UV-Vis Spectrophotometer

Objective: The study presents the validation protocol for the determination of total phosphorus content at parts per million (ppm) (μg/L) levels in animal feed by a UV-Vis spectrophotometer. Methods: The measured absorbance of solutions against the blank solution was at 400 nm with the spectrophotometer. A combined ammonium heptamolybdate tetrahydrate and ammonium monovanadate blue solution was used as a coloring reagent for detection. This method was validated by evaluation of statistical parameters such as linearity, sensitivity, limits of detection (LOD) and quantification (LOQ), precision, accuracy, and measurement uncertainty using a matrix blank (MB) against the phosphorus standard. Results: The Instrumental Detection Limit was 0.066 ppm and the Instrumental Quantification Limit was 0.22 ppm, respectively, while the phosphorus recovery and repeatability percent were 101.15% and 0.11%, respectively. However, the linearity of this method was 0.1 to 30 ppm. The measurement uncertainty of this method was 2.82%, following Commission Regulation (EC). Conclusion: The estimated parameters in the validation protocol, were found to meet the imposed performance criteria, and the procedure was validated for the intended use.

Impact of Green Synthesized Copper Doped Nanostructured Molybdenum Oxide Flakes on Micro Structural, Electrical, and Electrochemical Properties

In the present work, the different weight percentage (0, 2, 4, 6, 8, and 10 wt %) of copper (Cu) incapacitated MoO3 flakes were successfully green synthesized by combustion technique using precursor ammonium heptamolybdate tetrahydrate, fuel Shorea Robusta leaves extract, and copper nitrate trihydrate as dopant. XRD analysis reports that the synthesized Cu doped MoO3 material exhibits orthorhombic configuration with high crystallanity nature and the XRD pattern show a shift in diffractive peak towards lower diffractive angle as the Cu dopant percentage increases. FT-IR analysis shows the presence of stretching bond between molybdenum and oxygen atom (Mo=O) at 993cm-1. From SEM morphological analysis flake like structure was observed. The HRTEM studies shows d-spacing of 0.20 nm for 6 wt% Cu doped MoO3 flakes with irregular shapes. UV-DRS studies reports the bandgap ranges from 3.15 eV to 3.36 eV for different weight percentage Cu doped MoO3 flakes and for 6 wt% Cu doped MoO3 flakes obtained bandgap is less (3.15 eV). EIS studies reveal the impedance ranges from 180 Ω to 300 Ω. The bandgap and impedance results shows good conductivity for 6 wt% Cu doped MoO3 flakes compared to other synthesized weight percentage nanostructured Cu doped MoO3 flakes. The improved bandgap and impedance were observed for 6 wt% Cu doped MoO3. Hence, 6 wt% Cu doped MoO3 can be employed as anode electrode material for LIBs.

Glucose-assisted combustion synthesis of oxygen vacancy enriched α-MoO3 for ethanol sensing

The α-MoO3-based materials have been intensively investigated as chemiresistive-type gas sensors due to their excellent sensing performances for gas sensing applications. However, there still remains formidable challenges for developing a simple and scalable approach to synthesize α-MoO3 with controllable structures. Herein, we demonstrated a glucose-assisted combustion synthesis strategy for the synthesis of α-MoO3 materials with controllable structures. They were obtained by heat treatment of the gels containing ammonium heptamolybdate tetrahydrate and glucose. Owing to the coordination interactions between glucose and heptamolybdate, α-MoO3-2 sample obtained by adding 1.8 g of glucose featured the highest oxygen vacancy concentration with an O/Mo atomic ratio of 2.61. The gas sensing measurements indicated that α-MoO3-2 had excellent sensing performances for detecting ethanol. Such ethanol sensor displayed the lowest detection concentration of 5 ppm ethanol, high response of 3.86 toward 20 ppm ethanol, and wide detection range of 5–100 ppm. This study sheds light on preparation of metal oxides with controllable structures on a scalable way for various applications.

Impact of novel fuel extract variation on structural, electrical and electrochemical properties of nanostructured molybdenum oxide flakes

Nanostructured molybdenum oxide (α-MoO3) flakes were synthesized by solution combustion method using Shorea Robusta (Dipterocarpaceaefamily) leaves extract as a novel fuel and Ammonium heptamolybdate tetrahydrate (AMo) as the precursor. This article highlights the impact of fuel variation on structural, electrical and electrochemical performances of α-MoO3 prepared at different AMo to fuel ratio (1:0.25, 1:0.5, 1:1 and 1:1.5). The green synthesized α-MoO3were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer Emmett-Teller (BET), Scanning electron microscopy (SEM) equipped with EDAX, High resolution transmission electron microscopy (HRTEM), UV–Visible Diffused reflectance spectroscopy (UV–Vis DRS) and Electrochemical impedance spectroscopy (EIS). XRD analysis reveals that the prepared material exhibits α-MoO3 orthorhombic structure with high crystallinity. FT-IR studies confirm the presence of MoO at 991 cm−1. UV-DRS studies revealed the band gap varies from 3.80 eV to 4.25 eV for different fuel ratios. SEM studies illustrate the flake like structure. EIS studies reports the impedance varies from 300 Ω to 351 Ω. The band gap and impedance analysis of α-MoO3 prepared at 1:0.5 shows good conductivity compared with other ratios. HRTEM studies α-MoO3 (1:0.5) shows d-spacing of 24 nm and the selected area electron diffraction(SAED) pattern well matches with the XRD pattern. BET studies of α-MoO3 (1:0.5) shows the surface area of 6.27 m2g−1 with mean pore diameter of 7.26 nm. Inspected results shows improved structural, electrical and electrochemical performances for 1:0.5 α-MoO3 and hence it is proposed 1:0.5 α-MoO3 is suitable as electrode material for Li-ion batteries and sensor applications.

Convenient synthesis and Raman spectral characterization of diammonium monomolybdate(VI)

A convenient and cost-effective method is reported for the preparation of gram quantities of an ammonium-rich Mo compound viz. diammonium monomolybdate(VI) (NH 4 ) 2 MoO 4 ( 1 ). The process involves a thorough grinding of a commercial sample of ammonium heptamolybdate tetrahydrate (NH 4 ) 6 [Mo 7 O 24 ]·4H 2 O with an excess of ammonium bicarbonate followed by thermal treatment. The facile formation of ( 1 ) is confirmed by its characteristic Raman spectrum. The use of Raman spectroscopy to distinguish between tetrahedral monomolybdate(VI) and heptamolybdate, dichromate and monochromate(VI), paratungstate and monotungstate(VI) as well as the identification of the species present in ammoniacal solutions of MO 3 (M = Cr, Mo, W) are reported.

A new good thermal stability hybrid material based on heptamolybdate cluster: Synthesis and structural characterization

Abstract A new microporous polyoxomolybdate, (C4H7N2)9(NH4)3[Mo7O24]2•4H2O ([C4H7N2]+ = 2-methylimidazolium), was prepared at room temperature by reacting ammonium heptamolybdate tetrahydrate and 2-methylimidazole in a 1:4 molar ratio in water and characterized by infrared, TGA-DTA analysis and single-crystal X-ray diffraction. The compound is a heptamolybdate anion which crystallizes as a mixed salt of both ammonium [NH4]+ and 2-methylimidazolium [C4H7N2]+. The crystal structure of the compound is composed of [Mo7O24]6– clusters connected in a tridimensional network by [C4H7N2]+ and [NH4]+ cations and water molecules via hydrogen-bonding interactions. The relatively high thermal stability may be due to the existence of the network of hydrogen bonds and electrostatic interactions. Obtaining of compound from (NH4)6[Mo7O24]•4H2O shows that the transition from one polyoxomolybdate to another is possible through substitution reactions at room temperature, despite their stability. This material obtained could be used as catalyst and catalyst support.

Efficient photocatalytic degradation of environmental pollutant with enhanced photocarrier separation in novel Z-scheme a-MnO2 nanorod/a-MoO3 nanocomposites

Novel a-MnO2 nanorod/a-MoO3 nanocomposites were fabricated by simple template free methods. Hydrothermal and thermal treatment of ammonium heptamolybdate tetrahydrate in static air were applied for fabrication of MnO2 and MoO3 respectively. FT-IR, XRD, XPS, SEM, Raman, EDX, Point of zero charge, BET, DRS, PL, Photocurrent-time and TEM analyses were used to verify the a-MnO2/a-MoO3 structure and properties. A detailed study on photodegradation of acid blue 92 has been investigated under visible light irradiation. The MoO3 elevated the a-MnO2 nanorod photocatalytic activity and optical band gap investigation demonstrated that a-MnO2 /a-MoO3 heterojunction, is an active photocatalyst in visible light. Different parameters like catalyst dosage, organic dye concentration, calcination temperature, pH, weight percent ratio of MoO3 to MnO2 were optimized and kinetics study showed that degradation processes of acid blue 92 were first-order. Reaction mechanism was proposed based on the scavenger usage and radical trapping experiments. The as-prepared photocatalysts demonstrated excellent reusability capability and there were no obvious loss of activities after four cycles. High photocatalytic activities in a-MnO2/a-MoO3 nanostructure are attributed to the strong oxidative ability, efficient charge separation and transfer the electron-hole through the a-MnO2 and a-MoO3.

Effect of reaction temperature and reaction time on the structure and properties of MoS2 synthesized by hydrothermal method

AbstractIn this study, molybdenum disulfide (MoS2) nanostructures were synthesized by a facile hydrothermal process, using ammonium heptamolybdate tetrahydrate ((NH4)6Mo7O24.4H2O) and thiourea (CH4N2S) as the reactants. The effects of experimental parameters including reaction temperatures and reaction times on the structure and morphology of MoS2 have primarily been investigated. The morphology, microstructure, chemical composition and optical properties of as‐synthesized MoS2 were characterized using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), energy dispersive X‐ray spectroscopy (EDS), X‐ray diffraction (XRD), Raman and Photoluminescence spectroscopy. The FESEM and TEM results indicate that depending on the reaction temperature, the three types of morphologies of MoS2 crystals could be obtained. Morphologies of MoS2 changed gradually from aggregated particles to flake‐like structure, then finally to nanosheet morphology with increasing reaction temperature from 160 to 220 oC. However, it was found that the reaction time contributed significantly to the restacking and refinement of MoS2 crystal structure, rather than affecting the morphology of the investigated samples. Both XRD and Raman investigations reveal that the as‐synthesized MoS2 has a hexagonal phase structure (2H‐MoS2). Interestingly, the as‐prepared MoS2 nanosheets exhibit photoluminescence in the visible range with the emitted photon energy of ~1.81 and ~1.95 eV, these properties make MoS2 a promising candidate as the material of choice for next‐generation optoelectronic and photonic devices.

Influence of the annealing temperature on the formation of Mo17O47 and MoO3 nanoparticles and their Photocatalytic performances for the degradation of MB dye

The present research article is about the visible light photocatalytic degradation of Methylene Blue (MB) by aqueous heterogeneous medium containing orthorhombic phase of nanocrystalline (NCs) molybdenum oxide (MoO3). The two different oxidation forms of molybdenum oxides formed at annealing temperatures of 90 °C and 400 °C are Mo17O47 and α-MoO3 nanocrystals which are found to exhibit good photocatalytic activity. In the present work, a simple conventional wet chemical method has been used to synthesize molybdenum oxide nanoparticles (NPs) by combining ammonium heptamolybdate tetrahydrate (AHMT) with capped sodium dodecyl sulfate (SDS) and ethanol solution. The orthorhombic phase is present in the samples annealed at 90 °C, 200 °C, 300 °C, and 400 °C, respectively, and it is found that the orthorhombic phase is a highly stable phase in both Mo17O47 and α-MoO3. The photocatalytic activity of the synthesized samples is estimated by using MB degradation. The photocatalytic behaviors of the synthesized Mo17O47 and α-MoO3 nanostructures have been studied using the color degradation of MB. It is found that Mo17O47 and α-MoO3 with nanorods like structure has the potential to degrade the MB dye and for a time of 90 min, the degradation efficiency of Mo17O47 and MoO3 are 56.15% and 95.78%, respectively.

Chromatographic identification of "green capping agents" extracted from Nasturtium officinale (Brassicaceae) leaves for the synthesis of MoO3 nanoparticles.

A low-temperature, efficient and effective method was investigated for phytochemical hydroethanolic extraction of Nasturtium officinale (Brassicaceae). The phytocompounds of the selected plant leaves were identified by high-performance liquid chromatography, gas chromatography with mass spectroscopy, Fourier transform infrared spectroscopy, and ultraviolet-visible spectroscopy. Acetic acid, d-alanine, octodrine, decanoic acid, and cyclohexylethylamine were the major phytocompounds identified in N. officinale leaves with high similarity match and spectral purity. The reducing and stabilizing potential of the extracted phytochemicals was demonstrated by synthesizing the metal oxide nanoparticles (MoO3 ) by treating ammonium heptamolybdate tetrahydrate (H4 MO7 N6 O24 .4H2 O) aqueous complex with bioactive compounds of the leaves. The bio-synthesized MoO3 nanoparticles were characterized by ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, field emission-scanning electron microscopy, and gas chromatography with mass spectroscopy. Gas chromatography-mass spectroscopy identified acetic acid, d-alanine, and octodrine as stabilizing agents in the synthesis of MoO3 nanoparticles.

ATP Mimics pH-Dependent Dual Peroxidase-Catalase Activities Driving H 2 O 2 Decomposition

Adenosine triphosphate (ATP) is produced mainly in the mitochondrion, and its primary task is to function as a ubiquitous energy currency to meet the cellular metabolic demands in biological system...

Solution combustion synthesis of SrMoO4 nanophosphor using different molybdenum sources and study of its photocatalytic properties

The solution combustion method is applied to synthesize two different strontium molybdate (SrMoO4) samples referred to as SM1 and SM2, obtained from two different molybdenum precursors, namely molybdenum metal powder and ammonium heptamolybdate tetrahydrate. In the present work, we mean to study the influence of different molybdenum sources on the synthesis, particle size, surface area and photocatalytic degradation at different pH conditions. The comparison of phase formation and characteristic properties of both SM1 and SM2 was concluded using powder x-ray diffraction, scanning electron microscopy, transmission electron microscopy, BET specific surface area analysis and photoluminescence. The powder x-ray diffraction patterns reveal that both SrMoO4 nanophosphor is crystallized well with the tetragonal phase of the scheelite structure. The porous and agglomerated morphology of the obtained SM1 and SM2 was established by scanning electron microscopy. Transmission electron microscopy images exhibit that SM1 shows relatively lesser particle size (∼10–40 nm) when compared to SM2 (∼15–50 nm). SM1, with better textural properties, exhibits slightly better photocatalytic degradation of methylene blue dye with and comparable recycling ability with respect to SM2.

Facile template-free synthesis of 3D flower-like Bi2WO6/MoO3 nanocomposites with ultra-thin sheets and their associated photocatalytic properties under visible light irradiation

Bi2WO6 hierarchical multilayered flower-like assemblies were fabricated by a simple template-free method. This structure composed of a large number of interconnected nanoplates with a mean side length of ca. 20 nm. The unique design was created by nanosheets in all directions which provide high surface area. Numerous nanosheets promote charge carrier transport. Bi2WO6/MoO3 nanocomposites were synthesized by thermal treatment of ammonium heptamolybdate tetrahydrate in Bi2WO6 pores in static air at 400 °C. Prepared photocatalysts were characterized by SEM, TEM, XPS, XRD, BET, PL, IR and DRS. Bi2WO6/MoO3 demonstrated high activity in photodegradation of an azo dye and after 20 min of irradiation, the solution became colorless. Optimization of different parameters such as pH, catalyst dosage, calcination temperature, dye concentration, weight percent of MoO3 to Bi2WO6 was done. Photocatalytic mechanism proposed based on the scavenger usage as well as photoreaction kinetics were studied.