Calcined Samples Research Articles

Improved photocatalytic activity of SnO2-TiO2 nanocomposite thin films prepared by low-temperature sol-gel method

The objective of this research was to investigate how the photocatalytic activity of pure TiO2 can be improved by SnO2 modification. Different molar ratios of tin to titanium were prepared. The correlation between tin concentration and structural properties was investigated to explain the mechanism of photocatalytic efficiency and to optimize the synthesis conditions to obtain enhanced activity of the SnO2-modified TiO2 photocatalysts under UV-irradiation. The SnO2-modified TiO2 photocatalysts were prepared by a low-temperature sol-gel method based on organic tin and titanium precursors. The precursors underwent sol-gel reactions separately to form SnO2-TiO2 sol. The sol-gels were deposited on a glass substrate by a dip-coating technique and dried at 150 °C to obtain the photocatalysts in the form of a thin film. To test the thermal stability of the material, an additional set of photocatalysts was prepared by calcining the dried samples in air at 500 °C. The photocatalytic activity of the samples was determined by measuring the degradation rate of an azo dye. An increase of up to 30% in the photocatalytic activity of the air-dried samples was obtained when the TiO2 was modified with the SnO2 in a concentration range of 0.1–1 mol.%. At higher SnO2 loadings, the photocatalytic activity of the photocatalyst was reduced compared to the unmodified TiO2. The calcined samples showed an overall reduced photocatalytic activity compared to the air-dried samples. Various characterization techniques (UV-Vis, XRD, N2-physisorption, TEM, EDX, SEM, XAS and photoelectrochemical characterization) were used to explain the mechanism for the enhanced and hindered photocatalytic performances of the SnO2-modified TiO2 photocatalysts. The results showed that the nanocrystalline cassiterite SnO2 is attached to the TiO2 nanocrystallites through the Sn-O-Ti bonds. In this way, the coupling of two semiconductors, SnO2 and TiO2, was demonstrated. Compared to single-phase photocatalysts, the coupling of semiconductors has a beneficial effect on the separation of charge carriers, which prolongs their lifetime for accessibility to participate in the redox reactions. The maximum increase in activity of the thin films was achieved in the low concentration range (0.1–1 mol.%), which means that an optimal ratio and contact of the two phases is achieved for the given physical parameters such as particle size, shape and specific surface area of the catalyst.

A Study on Synthesis and Characterization of Dy-Doped La0.6Sr0.4Co0.2Fe0.8O3−δ via the Coprecipitation Method

The perovskite Lanthanum Strontium Cobalt Ferrite (LSCF) is investigated as the cathode material used in intermediate-temperature solid oxide fuel cells (IT-SOFCs). In the present study, La0.6−xDyxSr0.4Co0.2Fe0.8O3−δ (x = 0, 0.3, 0.6) was synthesized through the coprecipitation method. The obtained precipitate was calcined at 500, 700, 900, and 1000°С. Phase characterization of the synthesized LSCF and LDySCF powder before and after heat treatment at 700°С was carried out by X-ray diffraction (XRD) analysis. XRD patterns revealed that the perovskite phase was obtained at 700°С in all calcined samples. Chemical bond study to investigate the synthesis process was conducted using the Fourier transform infrared spectroscopy technique. Thermal analysis of DTA and TG has been utilized to investigate how the calcination temperature affects the perovskite phase formation. According to the STA results, the perovskite phase formation started at 551°С and completed at 700°С. The density values of synthesized powders were 6.10, 6.11, and 6.37 g·cm−3for the undoped and doped samples calcined at 700°С. Powder morphology was studied by field emission scanning electron microscopy (FE-SEM). The micrographs showed the spherical-shaped particles with the average particle size of 24–131 nm.

Study of the formation of acid‐based geopolymer networks and their resistance to water by time/temperature treatments

AbstractAcid‐based geopolymers are known for their high temperature resistance and good mechanical performances. Some compositions also exhibit water resistance, which make them suitable for outdoor applications. This work aims to understand accurately the steps occurring during the geopolymerization process and focuses on the type of networks forming at early stages of the reaction. The sample, prepared from metakaolin and phosphoric acid, has been analyzed at different durations and temperatures during its solidification, in order to identify which compounds would crystallize. The structural characterizations have been performed using Fourier transform infrared spectroscopy and X‐ray diffraction. Several Al–O–P compounds and especially AlPO4 polymorphs crystallize in these conditions. They belong to three families of aluminophosphates and are a reliable indication of the amorphous organization of the original sample. The first one is similar to the phases that appear in the phase transition sequences of silica, the second one is composed of AlPO4‐based zeolites, and the last one is characterized by the presence of aluminum in an octahedral network. The transitions between the different phases are also discussed. Finally, the water resistance of the calcined samples is improved, and the release of acidic species in the water is limited even after a calcination at low temperature.

Weight Loss during Calcination and Sintering Process of Na0.5Bi0.5TiO3–Bi1/2(Mg2/3Nb1/3)O3 Composite Lead-Free Piezoelectric Ceramics

(1 − x)(Na0.5Bi0.5)TiO3–xBi(Mg2/3Nb1/3)O3 ceramics with x = 0.00 mol.% (0BMN), 0.01 mol.% (1BMN), 0.03 mol.% (3BMN), and 0.05 mol.% (5BMN) were synthesized using a solid-state processing technique. The thermogravimetric analysis (TGA) of uncalcined samples up to 730 °C showed that the maximum weight loss was observed for 3BMN, whereas the minimum weight loss was attributed to the 0BMN sample. After that, calcination was performed at 800 °C for 4 h. The XRD of calcined samples showed the successful formation of the perovskite phase with no impurity phases. 1BMN and 3BMN samples showed some of the lattice strain; however, a morphotropic phase boundary (MPB) existed around x = 0.03 between the rhombohedral and tetragonal structure. The TGA of the green pellets showed weight loss up to the sintering temperature (1100 °C) and during the 3 h holding period. 5BMN showed the maximum weight loss up to sintering temperature, as well as during the holding period, whereas 0BMN displayed the minimum weight loss up to sintering temperature, as well as some weight gain during the holding period. The relative permittivity (εr) was maximum at low frequencies, but the addition of BMN improved the εr. The frequency dependence of dielectric loss (tanδ) showed that the maximum loss was observed for 3BMN at lower frequencies, and 5BMN showed the maximum loss at higher frequency among all samples.

Effective Dye Degradation Using Sol-Gel Synthesized Titania Nanostructures

Background: The organic effluents from industry remain one of the reasons for water contamination. By the natural degradation process, it is difficult to remove this; hence finding an effective solution for this is inevitable. TiO2-based materials have received enormous attention in the area of semiconductor photocatalysis, particularly for the degradation of organic dyes. This work emphasizes on the degradation of two industrial dyes methylene blue and rhodamine blue by visible light irradiation of TiO2 based nanoparticles. Methods: In the present study, pristine and La3+ and Ce3+ doped nanotitania were synthesized by the sol-gel method. The samples under investigation were characterized using X-ray diffraction, Transmission electron microscopy to study the variation of crystallite size and UV-Visible absorption spectroscopy. Results: The increase in crystallite size for the pristine samples calcined at various temperatures confirms the effect of calcination temperature. Also, the doping reduced the size of the synthesized nanotitania. Visible light extended absorption spectra have been observed for the calcined samples and Ce3+ doped nanotitania. The La3+ doped sample showed a blue shift in the absorption confirming quantum confinement. The photocatalytic activity in the context of degradation of certain industrial dyes such as methylene blue and rhodamine blue has been investigated for the samples. Conclusion: The studies found that nanotitania consisting of mixed anatase-rutile phase exhibits higher degradation efficiency than that of pure anatase or rutile samples. Besides, photocatalytic dye degradation has been significantly improved for Ce3+ doped nanotitania compared to the pristine sample.

Assessment of Gypsum And Limestone Rocks from Fat’ha Formation (m. Miocene) for Making Wallboard in The Makhmur Area – Northern Iraq

Five samples of gypsum and one sample of limestone were collected from an outcrop in Qara Chugh Anticline. The samples of gypsum were analyzed chemically before and after calcination. The purity of the samples of gypsum and limestone was calculated and the (H2O+) content of the calcined samples of gypsum was determined. The physical and mechanical properties of plaster of Paris produced from calcining the samples of gypsum were tested according to the Iraqi and American Standards. A wallboard sample was made using basic materials according to the American Standard. The chemical analyses of the samples of gypsum and plaster of Paris conform to the Iraqi and American Standards. The Fat'ha Formation rocks in the Makhmur area are suitable for making wallboard. The optimum conditions for calcining the studied gypsum rocks to produce plaster of Paris conforming to the standard specifications and suitable for the manufacture of wallboard are 130 °C for 1 hour.

Controlling the morphology of nanocrystalline Y(OH)3 powders synthesized by microwave-hydrothermal route and effect of annealing

Y(OH)3 is the main precursor material to inherit desirable morphologies for Y2O3. The Y(OH)3 and Y2O3 are an important substitution for luminescent matrix and useful in temperature sensing applications. Nanostructured and phase-pure Y2O3 is also used as an essential dispersoid for the oxide dispersion strengthened steels which are candidate materials for future fast breeder reactors. In the present work, the nanostructured Y(OH)3 is prepared indigenously by the microwave-hydrothermal route which is appropriate to provide-uniform heating to the material and the hydrothermal-pressure environment plays a major role in the growth kinetics of morphology. The synthesis was carried out at various microwave powers of 700 and 800 W to obtain the different morphologies of tubular and rod-like structures, respectively. The morphology is attributed to the influence of heat-rate on the variation in hydrothermal pressure governed by microwave power. The morphologies remain the same on calcination 800 °C. As-synthesized powder samples showed hexagonal structure whereas the cubic structure was observed for those calcined at 800 °C for both morphologies. The hydroxide vacancies lead to form a cubic structure that has a larger unit cell. The yttrium oxides showed lattice compaction for the rod-like structure but yttrium hydroxides did not depict any difference in the lattice for the tubular and rod-like morphologies. Likewise, Raman spectroscopy analysis confirmed the formation of hexagonal and cubic phases for the as-synthesized and calcined nanopowder samples, respectively.

In situ aqueous phase hydrodeoxygenation of methyl palmitate to hydrocarbons on Ni catalyst derived from the reduction of LaNiO3 perovskite

A series of Ni–La–O-T catalysts (T-calcination temperature) were prepared via the sol–gel process followed by the calcination. They were tested for in situ aqueous phase hydrodeoxygenation (HDO) of methyl palmitate using methanol as hydrogen donor. In the calcined samples, NiO and La2O2(CO3) formed in Ni–La–O-550 and Ni–La–O-650. Apart from NiO and La2O2(CO3), there was LaNiO3 perovskite in Ni–La–O-750. Only LaNiO3 perovskite existed in Ni–La–O-800. After the reduction at 650 °C, metallic Ni and La2O3 appeared in all the catalysts. During in situ HDO, decarbonylation/decarboxylation was dominating, accompanying with the C–C bond hydrogenolysis and aqueous phase reforming of alkanes. H2 was generated from not only the aqueous phase reforming of methanol but also that of alkanes. Liquid C6–C16 alkanes were produced and C15 alkane was main product. Among the catalysts, Ni–La–O-750 afforded the highest activity for deoxygenation, C–C bond hydrogenolysis and aqueous phase reforming. The reaction temperature, reaction time, water and methanol loadings remarkably affected the products distribution. At a suitable condition, the yield of C6–C16 alkanes reached 71.1% on Ni–La–O-750. Additionally, Ni–La–O-750 was also very active for in situ HDO of methyl palmitate without methanol, however, the C–C bond hydrogenolysis was more serious.

A new approach for the synthesis of monodisperse zirconia powders with controlled particle size

In this work, the synthesis of hydrous zirconia by controlled double-jet precipitation (CDJP) was carried out in the pH range from 3 to 8. The evolution of particle shape and size during precipitation was investigated. It was found that at pH 3, 7, and 8 during the precipitation process there is no significant change in particle size, the suspension was gel-like, particles actively aggregated during drying. A gradual increase in particle size and a decrease in particle size dispersion specific for layer-by-layer aggregation was observed during CDJP at pH 4 to 6. The resulting particles do not aggregate and retain a rounded globular shape with a narrow size distribution during drying. Samples obtained at a pH above 6 are characterized after drying by a high specific surface area and porosity, as well as a reduced content of NO3- ions. The effect of pH precipitation on the phase composition and crystallite size of calcined samples was discussed.

Phase formation, structure and properties of light-weight aluminosilicate proppants based on clay-diabase and clay-granite binary mixes

One of the drawbacks of fusible clays is the narrow sintering interval due to a sharp increase in the amount of iron-silicate melt at a temperature of 1000–1100 °C, which hardens in the form of a glass phase upon cooling. This leads to a relatively low mechanical strength of the calcined samples and causes the danger of melting the granular material surface from such clays during the firing process. To increase the strength of samples of fusible clays, the influence of diabase and granitoid rocks was considered. It was found that the strengthening effect of diabase and granitoid rock additives in an amount of 20–50% in a mixture with fusible clay is due to an increase of total content of the crystalline phase (mullite, cristobalite and residual quartz) from 18–20% in clays without additives to 22–28 % - in mixtures with diabase and to 28–34% - with granitoid additives) at a temperature of 1050–1100 °C. This increase is due to the activation of synthesis processes of secondary mullite and crystallization from alkali-rich feldspar melt of amorphous silica, released from the structure of clay minerals. The established influence of the igneous rocks used made it possible to develop compositions and propose process flow sheet for producing aluminosilicate proppants based on fusible clays. The use of granitoid and diabase rocks in an amount of 20–70% with fusible clays produces lightweight aluminosilicate proppants with bulk density of 1.40–1.46 g/cm3 at temperature range of 1050–1100 °C, which can endure destructive pressures up to 34.5–52 MPa.

Synthesis of Hierarchical Porous Silica by Sol‐Gel of Sodium Silicate and Nanoemulsion Templating: Effective Combination Conditions

AbstractHierarchical porous materials have attracted a considerable attention owing to the increased interest in their applications. Hierarchical Porous Silica (HPS) was synthesized by combining the sol‐gel of sodium silicate (SS) and oil in water nanoemulsion (O/W‐NE) templating. The oil droplets of NE acted as pore forming agent and the sol‐gel built the silica framework. The O/W‐NE was prepared by a low energy method, i. e., the phase inversion composition (PIC) method. The influence of pH of SS and NE on HPS was studied. The volume of ammonia, used to induce gelling, was studied as a factor influencing the HPS. The calcined samples were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), FTIR, N2 adsorption and small‐angel X‐ray scattering (SAXS). The results show that the microstructure is highly affected by pH and can be; macropores inserted in a dense matrix; a blend of a dense and a porous structure; or fully hierarchical porous silica. HPS has a specific surface area of 240 m2/g and a large pore volume (1.5 cm3/g) and a surface roughness of 2.95.

Role of calcination on geopolymerization of lateritic clay by alkali treatment

In the present study, the role of calcination of a low iron lateritic clay sample was investigated to synthesize the geopolymer. The analyses like X-ray fluorescence (XRF) spectroscopy for chemical composition, X-ray diffractometry (XRD) for mineral composition, and Fourier transform infrared (FT-IR) spectroscopy & scanning electron microscopy (SEM) for structural changes upon calcination at 500, 700 and, 900 °C were used to assess the suitability of selected lateritic clay sample for geopolymer. The drop in electrical conductivity and greater consumption of calcium hydroxide by CS-900 confirmed its potential reactivity than CS-700, CS-500, and CS-Control. The quality of geopolymer derived from un-calcined and calcined lateritic clay samples by alkali activation was evaluated by comparing results of compressive strength, water absorption test, and stability in the aggressive environment of chloride, FT-IR, XRD, and SEM analyses. The experimental results reveal that the quality of geopolymer enhances as the calcination temperature of the lateritic clay sample increases, However, calcination of the lateritic clay sample at 900 °C gives significant results and yield good quality geopolymer with 24.8 MPa of compressive strength, 7.07% of water absorption and 2.22% loss in mass in an aggressive environment.

Cold sintering of as-dried nanostructured calcium hydroxyapatite without using additives

A novel low-temperature densification method of nanocrystalline calcium hydroxyapatite (HAp) at a temperature as low as 200 °C with no liquid additives is investigated. To understand the underlying mechanism of the low-temperature sintering of hydroxyapatite, two types of lab-synthesized nanocrystalline HAp, dried (110 °C, 12 h) and calcined (1000 °C, 2 h), were subjected to cold sintering conditions (200 °C, 500 MPa) and compared thoroughly. The dried samples were found to be nanocrystalline, enveloped by an amorphous shell, whereas the calcined samples were fully crystalline, as confirmed by X-ray diffraction, transmission electron microscopy, and solid-state nuclear magnetic resonance techniques. A relative density of 98.8% was achieved for the dried samples; however, the calcined samples could not be sintered. This indicates a clear dependence of densification on the surface chemistry of the nanocrystals involving rearrangement and dehydration of the amorphous layer present on the surface of the nanocrystals under the influence of applied pressure and temperature. Moreover, the calcined sample, which had a fully developed crystalline structure, did not undergo sintering, even with the use of added water. Therefore, it is demonstrated that wet-precipitated and dried nanocrystalline HAp can be cold-sintered to full densification for applications in biomedical materials or radioactive waste immobilization of volatile radionuclides at a considerably low temperature, without the addition of sintering aids.

Interdependence of piezoelectric coefficient and film thickness in LiTaO3 cantilevers

AbstractElectromechanical energy demands on homogenous thick films of piezoceramics with sufficiently large piezoelectric constant and reproducible performance. Single‐phase LiTaO3 films deposited by sol‐gel processing have been fabricated as cantilevers to investigate the interdependence of dielectric and piezoelectric properties as a function of film thickness. Phase pure LiTaO3 films with varying thickness in the range of 2.07‐4.37 µm on stainless steel substrates were obtained after calcination of samples at 650°C. The relative permittivity of optimized spin‐coated films peaked at 479.73 (1 kHz), whereas the piezoelectric coefficient (d33 mode) determined by piezoresponse force microscopy was in the range of 21‐24 pm/V. The effect of poling was studied through the butterfly and phase curves. A figure of merit (FOM) up to 3.29 (10−18 m2/V2) was determined for cantilever devices, which were able to generate a peak‐to‐peak voltage of 0.046‐0.15 V using a 1 MΩ resistor as an impedance load at a fixed acceleration of 1.5 m/s2. While the power density was in the range of ~4‐20 × 10−9 W/m3, which increased with the increasing film thickness. The leakage current density decreased in the range of 4 × 10−5‐6 × 10−7 A/m2 in the same direction. As both ferroelectric and piezoelectric properties of LiTaO3 films are dependent on film thickness, an optimal energy conversion efficiency was obtained for a thickness of ~3 µm. Furthermore, these devices were tested up to a temperature of 150°C for voltage generation. Given the need for lead‐free piezoelectric materials for environmental applications, these LiTaO3 cantilevers are very promising for vibrational energy harvester (VEH) applications especially due to their cost effectiveness, small size, stability at higher temperatures, and repeatable properties, which makes them suitable for MEMS devices for industrial applications.

Preparation of Ce-doped ZnO hollow spheres and their application as a light scattering layer in dye-sensitized solar cells

Ce-doped ZnO hollow spheres (Ce@ZHSp) with various Ce-contents of 0, 0.25, 0.50 and 1.0 mol% were synthesized via a template-free hydrothermal method. The calcined samples were characterized using XRD, FESEM, TEM, BET–BJH and UV–Vis spectroscopic techniques. The analytical results showed that all the samples possessed a hexagonal wurtzite structure. The crystallite size of Ce@ZHSp decreased with increasing Ce-content. Calcined samples had a hollow sphere morphology with an average diameter range of 4.63–5.16 µm. Diffuse reflectance was increased by adding an appropriate Ce-dopant of 0.25 mol% into the ZnO hollow spheres. The energy-conversion efficiency of a dye-sensitized solar cell was examined under the A.M. 1.5 direct spectrum. These results showed that the highest efficiency was derived from a bilayer photoanode using 0.25 mol% Ce-doped ZnO hollow spheres as a light scattering layer. This finding was related to an increase in the amount of dye adsorption and a photonic reflection effect originating from the relatively larger particle sizes with higher porosity compared to the other samples.

Assessment of composition and calcination parameters in Fischer-Tropsch synthesis over Fe–Mn–Ce/γ-Al2O3 nanocatalyst

The effects of nanocatalyst composition and calcination parameters on the performance of the Fe–Mn–Ce ternary nanocatalysts supported on alumina granules in a laboratory fixed bed microreactor have been evaluated. Nanocatalysts were synthesized by incipient wetness impregnation under vacuum method (simultaneous impregnation of metal species). The samples used for hydrogenation of carbon monoxide via Fischer-Tropsch synthesis. The optimum nanocatalyst composition for production of light olefins (C=2 – C=4) from synthesis gas is 75 wt%Fe–20 wt%Mn–5 wt%Ce. The calcination parameters (temperature, time and atmosphere) were investigated and their effects on the structure and performance of the nanocatalysts were determined. The maximum ratio of olefins/(methane + paraffin) and the best activity and selectivity belonged to the nanocatalyst which was calcined in static air at 500 °C for 7 h. The nanocatalyst precursors and calcined samples (fresh and used) were characterized by XRD, N2 physisorption, FE‒SEM, EDAX, MAP, TG, DSC, and H2–TPR. The present study results confirm that the structural, morphological and physic-chemical properties of the nanocatalyst have been impressed with metal species and calcination parameters.

Role of Cationic and Anionic Dopants on the Structural, Morphological, Optical and Magnetic Properties of Lead Oxide Nanocrystals Prepared by Solvothermal Method

A facile and simple microwave assisted solvothermal technique was adopted for the synthesis of undoped and doped (Mn2+, S2–) lead oxide nanoparticles. Thermogravimetric analysis and differential thermal analysis were carried out to realize the thermal behaviour of PbO nanoparticles. The synthesized nanoparticles were annealed at about 400 ºC. The calcined samples were characterized by powder X-ray diffraction, SEM, EDX, UV spectroscopic analysis and VSM measurement. The diffraction patterns of the prepared nanoparticles showed the formation of an orthorhombic phase of lead oxide. All the samples were in nano- regime with an average grain size of 22-26 nm. Spherical morphology of the samples was revealed in the SEM micrographs. EDX pattern confirmed the presence of cationic and anionic dopants. The band gap energy values range from 4.2 to 5.6 eV. The VSM measurement revealed that the sample has weak ferromagnetic nature.

Structural and magnetic properties of Mn doped cobalt ferrite nanoparticles synthesized by Sol-Gel auto combustion method

Co1-xMnxFe2O4 (with x = 0.0, 0.2, 0.4, 0.6) ferrites nanoparticles were synthesized by the sol–gel auto combustion method. The crystal structure, morphology, elemental analysis and magnetic properties of the samples were systematically investigated using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman Spectroscopy, High resolution scanning electron microscopy (HRSEM), Energy dispersive X-ray spectroscopy (EDX), and Vibrating sample magnetometer (VSM) analysis. The XRD results confirmed the cubic spinel structure up to x = 0.2. Scherrer and Williamson-Hall (W-H) method were applied to determine crystallite size and strain present in the sample. The FT-IR spectra showed the absorption peaks confirmed the presence of metal–oxygen stretching bands in Mn doped cobalt ferrites. Raman spectra showed four strong and sharp modes, identifies the cobalt ferrite phase. HRSEM images clearly showed that Co1-xMnxFe2O4 (with x = 0.0, 0.2, 0.4, 0.6) ferrite grains appear in spherical shape with less agglomeration. The elemental analysis (EDX) was performed for the above samples and their spectrum confirmed the presence of Co, Fe, Mn and O elements in the prepared Mn doped Cobalt ferrite materials. The magnetic measurements of the calcined samples were carried out at room temperature using vibrating sample magnetometer. By the substitution of cobalt magnetic ions with Mn2+, it is possible to tune the magnetic properties of cobalt ferrite as a promising material for various technological applications.[copyright information to be updated in production process]

Oxygen vacancy engineering in Fe doped akhtenskite-type MnO2 for low-temperature toluene oxidation

To clarify the discrepancies between oxygen vacancies (VO) types and concentrations, we designed two types of VO by substituting Mn4+ in akhtenskite-type MnO2 with low-valence manganese (e.g. Mn3+) or iron (e.g. Fe3+), denoted as VO (MM) and VO (FM), respectively. The concentration of VO was adjustable by the varied sample calcination temperature. The catalysts with more VO (FM) achieved higher toluene specific reaction rate and better stability than those of Mn3+ doped MnO2, ascribing to the chemical and reactive difference of their different Vo types. Toluene specific reaction rate have been quantitatively calculated to estimate the contribution of VO on catalytic performance and followed the order of F1M4 (2.73 mmol/(g h)) > F2M13 (2.29 mmol/(g h)) > F1M14 (1.52 mmol/(g h)) > Mn (0.91 mmol/(g h)) > F1M2 (0.89 mmol/(g h)) at 200 °C (Mn, F1M14, F2M13, F1M4 and F1M2 represented pure MnO2 and Fe doped MnO2 with Fe/Mn = 1/14, 2/13, 1/4, and 1/2, respectively). Additionally, the VO concentrations of as-prepared catalysts decreased with the increasing calcination temperature, which then led to the declining activity for toluene oxidation. Furthermore, in situ DRIFTS spectra demonstrated that the higher concentrations of VO (FM) sites accelerated the transformation of intermediates from benzaldehyde to benzoate, which was the intermediate to be further oxidized into CO2 and H2O.

To study the structural properties of cobalt doped tin oxide nanostructured by using Williamson-Hall and size-strain plot methodology

Nanocomposites are the materials which are synthesized with the combination of two or more different materials comprising multiple domains and at least one phase domain in the nanometre range (1 nm-100 nm). Nanocomposites materials have significant advanced properties and application relative to individual nonmaterial adhere cumulative properties of host and guest material. In present work, nanocomposite of tin oxide doped with cobalt oxide was synthesized by applying chemical route method assisted by microwave. Various characterization techniques were applied to characterize the as-synthesized and calcined samples of Cobalt doped SnO 2 nanostructured materials such that diffraction caused by X-rays, infrared spectroscopy (IR). From diffraction caused by X-rays result analysis, it was observed that cobalt is substituted into the lattice position of the parent atom of Tin. The FTIR photograph study reveals that the presence of both constituents in the synthesized samples at their relative position (cm −1 ). The estimated crystallite/grain size of Cobalt doped SnO 2 nanostructured materials obtained from Debye-Scherrer formula was compared with Williamson Hall method and in addition to that the various peak broadening were investigated. From experimental results it was concluded that the crystallite/grain size of nanostructured material were decrease with increasing calcinations temperature due to lattice strain and dislocation in atomic structure from the rearrangement bonding connection between the atoms of tin oxide and cobalt.