Solution Combustion Reaction Research Articles

MoO3 Nanoparticles for enhanced photocatalysis, antioxidant activity and some selected biomedical applications: Perioria pinnatum leaf extract assisted with green synthesis and Characterization

Molybdenum oxide nanoparticles were prepared in a single step by a solution combustion reaction using ammonia molybdenum powder as precursor and Perioria pinnatum leaf powder as a novel fuel. Crystalline phase and morphology of the products were studied systematically characterized by PXRD, FESEM-EDS, UV-Visible, FESEM and FT-IR analysis techniques. Results show a variety of MoO3 nanoparticles within the size range of 10–80 nm. Furthermore, micro rods and micro sheets were also obtained through this method whose length varied in the order of microns. The synthesized MoO3 nanoparticles as versatile biological agents.

Magnetite nanoparticles obtained by solution combustion synthesis

This research presents a comprehensive investigation into the synthesis and characterization of magnetite nanoparticles through solution combustion reactions ignited by conventional means. In addition to the structural and compositional findings, this study's main investigation results include the specific surface area measurements conducted using the BET method. The analysis revealed specifi c surface area values for the synthesized magnetite nanoparticles at varying propellant-to-oxidant ratios, demonstrating a substantial decrease in specific surface area as the ratio increased. Specifically, specific surface areas of 72.203 m2/g for the 1:1 ratio, 22.240 m2/g for the 1:1.5 ratio, and 9.204 m2/g for the 1:2 ratio were determined. Furthermore, calculations based on the BET results and assuming spherical magnetite nanoparticles provided average particle sizes of 16±1 nm for the 1:1 ratio, 51±2 nm for the 1:1.5 ratio, and 125±4 nm for the 1:2 ratio. These findings highlight the impact of synthesis parameters on the nanoparticles' surface area and size, shedding light on their potential applications in various fields, including nanomedicine and magnetic diagnostics. Overall, this research contributes valuable insights into the synthesis, characterization, and tunable properties of magnetite nanoparticles, offering potential avenues for their utilization across diverse industries.

Combustion Synthesis and Photoluminescence Study of Sr3Y1-x(BO3)3: xPr3+ (0.01 ? x ? 0.05) Red Borate Phosphor for Near Blue Pumped WLED

Abstract: A red borate phosphor Sr3Y1-x(BO3)3: xPr3+ ( 0.01 ≤ x ≤ 0.05 ) was prepared by using a solution combustion reaction method, and its photoluminescence property is investigated. The synthesized phosphors were characterized by X-ray diffraction (XRD), scanned electron microscope (SEM) and photoluminescence (PL). Their excitation bands at 375, 384 and 395 nm are originated from the transitions of 3H4→3P2, 3H4→3P1 and 3H4→3P0 of Pr3+ ion. Under375nm nm excitations, the emission of Pr3+ at 595, 614 and 632 nm are attributed to 1D2→3H5, 3P0→3H6 and 3P0→3F2. The Commission International de Eclairage (CIE) chromaticity coordinates are (X = 0.67745889, Y = 0.322362077) for Sr3Y1-x(BO3)3: xPr3+ . The result shows that Sr3Y1-x(BO3)3: xPr3+ is promising candidate for red phosphors in the fabrication of pc-WLED and in blue LED chip WLED.

Rapid solution combustion synthesis of novel superfine CaLaAl1-xCrxO4 red ceramic pigments

Superfine CaLaAl1-xCrxO4 (x = 0.02, 0.05, 0.08, 0.10) red ceramic pigments have been prepared by solution combustion reaction and subsequent high-temperature calcination. All of the pigments were characterized by X-ray diffraction (XRD), Field scanning electron microscopy (FESEM), UV–Vis spectrophotometry, Laser particle size analyzer and CIE L*a*b* spectrophotometry. Moreover, the effects of the doping amount of Cr3+ ion, calcination temperature, salt assistance and synthetic routes on chromatic performance and particle size distributions of the pigments were also investigated. The results showed that CaLaAl1-xCrxO4 pigment particles prepared via solution combustion reaction and subsequent calcination were well-dispersed and uniform in size. With the increase of doping amount of Cr3+ ion, the brightness value L* of CaLaAl1-xCrxO4 pigments decreased obviously and the redness value a* increased gradually. When x = 0.08, it showed the best chromatic performance (L* = 39.37, a* = 21.33, b* = 13.99). In addition, the synthetic pigments possess excellent high temperature stability which is conducive to the application of ceramic pigments. Most importantly, the synthetic method of CaLaAl1-xCrxO4 red ceramic pigments is not only cheap in raw materials, but also easy to industrialize.

Deposition of Vanadium-Containing Yellow Pigment onto Marshalite Particles through Solution-Combustion Reaction

Deposition of Vanadium-Containing Yellow Pigment onto Marshalite Particles through Solution-Combustion Reaction

Solution Combustion Synthesis of YVO4 Nanopowder Using V2O5.nH2O Gel: Photodegradation Studies

In the present work, yttrium orthovanadate (YVO4) nanopowder has been synthesized via solution combustion route using citric acid as fuel. The primary aim is to establish a facile solution combustion reaction to produce YVO4 nanopowder with lower band gap using vanadium pentoxide (V2O5.nH2O) gel as precursor and then investigation of its photocatalytic activity against anionic and cationic dyes in presence of visible light. The powder X-ray diffraction (PXRD) analysis reveals the formation of pure YVO4 with tetragonal phase having crystallite size ∼30.95 nm. Scanning electron micrograph (SEM) exhibits highly porous nature of the product. Breauner-Emmet-Teller (BET) surface area analysis of YVO4 nanopowder shows a relatively large specific surface area of ∼46.57 m2.g–1. Transmission electron microscopy (TEM) exhibits uniform particle size distribution with average particle sizes varying in the range of 20-100 nm. The band gap of 2.16 eV is calculated using the ultraviolet diffuse reflectance spectrum (UV-DRS) of YVO4. The photoluminescence spectrum of YVO4 nanopowder shows emission peak at 572.2 nm. The photocatalytic degradation of methylene blue (MB) using YVO4 as photocatalyst shows 92% decolorization in presence of visible radiation. Photocatalytic activity has also been extended to investigate the degradation of amaranth dye and rhodamine-B (Rh-B) under visible light irradiation which reveals 80% degradation of amaranth dye but Rh-B shows only 65% decolorization using YVO4 nanopowder. Hence YVO4 nanopowder shows good photocatalytic activity for MB and amaranth dye compared to Rh-B.

Thermal analysis of the products of SCS of zinc nitrate with glycine and citric acid

The composition of powders produced in reactions of Solution Combustion Synthesis (SCS) of zinc nitrate with glycine and a mixture of glycine and citric acid has been studied. The precursors formed on completion of solution combustion reactions were established to contain ZnO and up to 7 wt% of carbonaceous fragments due to incomplete oxidation of fuel. The latter are mixtures of residual carbon (0.2−3 wt%) and the fragments of citric acid decomposition, bound carbon, (0.6–4.4 wt%), which are strongly disordered carbon structures in nature, including amorphous ones. The performed thermal analysis of precursors and modeling allow us to suppose that the process of additional oxidation takes place in two stages – at 240−280 °C (oxidation of organic fragments) and 410−424 °C (oxidation of residual carbon) and is incomplete in character. It was shown that the complete removal of the carbonaceous fragments of organic fuel needs the temperatures close or over 900 °C. The best conductivity of ZnO were 1.13·10−7 and 9.19·10−8 S/cm after SCS and annealing 650 °C, respectively.

Dielectric and electrical studies on iron oxide (α-Fe2O3) nanoparticles synthesized by modified solution combustion reaction for microwave applications

Hematite (α-Fe2O3) nanoparticles were synthesized by modified solution combustion method using a mixture of hexamethylenetetramine (HMTA) and glycine fuels at fuel to oxidant molar ratio (ϕ = 1) and fuel (HMTA) to fuel (glycine) weight ratio (1:3). DC-conductivity and dielectric studies of (α-Fe2O3) nanostructures were reported as a function of temperature. Above room temperature (RT), the conductivity showed an increasing trend with temperature which confirmed the semiconducting behaviour of the material. The conductivity behaviour followed Motts law which confirmed the three dimensional variable range hopping (3D VRH) mechanism in the synthesized system. Dielectric studies were carried out at room temperature with frequency range (1000 Hz to 1.5 MHz) as well as varying temperature (100 °C to 400 °C) at different frequencies (0.1 MHz, 0.3 MHz, 1 MHz, 1.3 MHz, and 1.5 MHz).The dielectric permittivity (є’)and tangent loss (tan δ) was found to increase with increase in temperature. In this synthesised material low value of dielectric loss was observed which depicted these materials as potential candidates for microwave applications. More than that studied material was characterised by Raman spectroscopy which revealed that seven active Raman modes were present with different intensities, namely two “A1g” modes (225 and 498 cm−1) and five “Eg” modes (247, 293, 299, 412 and 613 cm−1). The most representative band present in the synthesised iron oxide nanoparticles was found at 225 cm−1.

A comparative study of the structural, magnetic transport and electrochemical properties of La0.7Sr0.3MnO3 synthesized by different chemical routes

A comparative study of the structural, magnetic, transport and electrochemical properties of the La0.7Sr0.3MnO3 (LSMO) synthesized by sol–gel, solution combustion and solid-state reaction has been discussed in details. Synthesis process controls the structure and morphology of the material which determine the overall characteristics of the material. The sol–gel and solution combustion method provide nanocrystalline material with an average particle size of 23.03 nm 17.9 nm, respectively; while, microcrystalline material with an average particle size of 160 nm is synthesized by solid-state reaction method. The magnetic properties of the material are improved with an increase in particle size from nanoscale to microscale, while resistivity increases with a reduction in the size of the material. The LSMO synthesized by the sol–gel method shows the highest magnetoresistance of 32.3% at 10 K with a 1T magnetic field. The solution combustion method provides LSMO nanoparticles with large surface area and porosity which results in its better electrochemical behavior as compared to the LSMO synthesized by sol–gel and solid-state reaction.

A reddish-orange emitting samarium doped α-Na3Y(VO4)2 nanocrystals for single phased UV excitable white light applications

Nanocrystals of samarium doped sodium yttrium vanadate have been synthesized by citrate based solution combustion reaction method for the first time. X-ray powder diffraction analysis and transmission electron microscopic analysis revealed the highly crystalline nature and uniform spherical morphology of the sample. The strong and broad band observed in the UV–Vis absorption spectrum as well as in the photoluminescence excitation spectrum point to the efficient energy transfer from vanadate to Sm3+ ion. Under the excitation of near ultraviolet (310 nm), α-Na3Y1-xSmx(VO4)2 exhibit reddish orange emission with high purity and the optimal doping concentration of Sm3+ ion is found to be about 2 mol %. Unlike mostly reported samarium doped phosphors, red emission (4G5/2 → 6H9/2) is more intense compared to the orange emission (4G5/2 → 6H7/2) in the present system. The main reason for concentration quenching is determined to be dipole-dipole interaction leading to cross relaxation. Strong sensitization of Sm3+ ion via host, least chance for re-absorption of blue-green emission due to the weak direct f-f excitation of Sm3+ ion and high purity reddish-orange emission suggests samarium doped α-Na3Y(VO4)2 nanocrystal as a potential nanophosphor in the field of single phase white light generation.

Application of Design of Experimental Technique for Optimization of Product Characteristics in the Solution Combustion Processing of Phase Pure Nano-HAp

Calcium hydroxy apatite, Ca 10 (PO 4 ) 6 (OH) 2 (HAp) nano-sized biomaterial was processed chemically by solution combustion method using calcium nitrate-di-ammonium hydrogen orthophosphate and glycine as fuels. Calcium Hydroxyapatite is an important bio-material for orthopedic applications. A series of solution combustion reactions were used to optimize the process parameters for synthesis of very fine HAp bio-ceramic powders. The combustion flame temperature (T f ) at stoichiometric fuel to oxidant ofthe solution combustion process was calculated to be 883° C. In the present work, correlations of various process parameters and the flame temperature as well as the specific surface area (SSA) of as synthesized powder were established. Both Taguchi and a regression model were used in this process to correlate the input parameters and output parameter of this system. The adequacy ofthe mathematical model was justified by using the analysis of variance technique. In this present investigation, nano-sized particles in the range of 20-130 nm was successfully processed through optimized process parameters.

Effects of heat-treatment on photoluminescence properties of MgAl2O4:Eu3+ red phosphors synthesized by a solution combustion method

Abstract To investigate the influence of annealing temperature on the structure and photoluminescence property, 5% wt. Eu3+ doped MgAl2O4 ceramics have been synthesized by a solution combustion reaction and thermally treated at 700, 800, 900, 1000, 1100, and 1200 °C. Powder XRD indicate that pure spinels were synthesized and the crystallinity increased with the increase of the heat treatment temperature. Low temperature heat capacities of these phosphors were measured and the data were fitted by T3 Debye model. The obtained Debye temperature of sample show positive relationship with the calcine temperature. Our results suggest that the heat treatment improves the crystallinity and decreases the structure defects of MgAl2O4:Eu3+. The SEM shows spongy structure of the particles is dependent on the calcine temperature. These phosphors exhibit hypersensitive red emission peaking at 613 nm, which corresponds to the electric-dipole 5D0 - 7F2 transition of Eu3+ ions. Comparison between the excitation and emission spectra has shown modification of their spectroscopic characteristics. The MgAl2O4:Eu3+ calcined at 900 °C shows the best performance based on the dominant red (5D0-7 F2) emission and the effective emission excited by near-UV 394 nm show potential applications in solid state lighting.

An extensive study on the synthesis of iron based magnetic aluminium oxide nanocomposites by solution combustion method

In the present study, it was aimed to investigate the synthesis of iron based magnetic aluminium oxide nanocomposites (IMANCs) by solution combustion (SC) method using various fuel types at various amounts. IMANCs were synthesized using aluminium nitrate and iron nitrate as oxidizers. Urea, glycine and sucrose were chosen as fuel types at various amounts, respectively, to examine their effects on size and morphology of nanocomposites synthesized. The chemical compositions, morphologies and thermal behaviors of IMANCs synthesized were compared with data obtained from characterization studies using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS), Thermogravimetric and Differential Thermal Analysis (TG/DTA), Fourier Transform Infrared Analysis (FT-IR), Surface Area and Porosity Analyzer. The characterization studies revealed that IMANCs were synthesized successfully by SC method with nanoscale properties. It was found that IMANCs synthesized using stoichiometric amount of glycine had porous and smaller particle size with higher surface area compared to other samples synthesized by urea and sucrose, respectively. There is no documentation found on glycine based synthesis of IMANCs by SC method in the literature so far. Additionally, this original paper is the first report on the synthesis of IMANCs by applying calcination and reduction processes following SC reaction using various fuel types at various amounts. It was resulted that the samples synthesized by SC method had smaller particle sizes compared to the samples which were synthesized by applying calcination and reduction processes following SC reaction using stoichiometric amount of urea, glycine and sucrose as fuel types, respectively.

Synthetic Access to Cubic Rare Earth Molybdenum Oxides RE6MoO12−δ(RE = Tm–Lu) Representing a New Class of Ion Conductors

Materials crystallizing in highly symmetric structures are of particular interest as they display superior physical properties in many relevant technological areas such as solid oxide fuels cells (SOFCs), catalysis, or photoluminescent materials. While the rare earth molybdenum oxides RE6MoO12 with the large rare earth cations RE = La to Dy crystallize in a cubic defect fluorite structure type (Fm3m, no. 225), the compounds with the smaller cations RE = Tm–Lu could hitherto only be synthesized in the rhombohedral defect fluorite structure type (R3, no. 148). In the following, new low temperature access to the rare earth molybdenum oxides RE6MoO12−δ (RE = Tm–Lu) crystallizing in the highly symmetric cubic bixbyite structure type (Ia3, no. 206) will be discussed. The three-step method comprises preparation of the rhombohedral phases by solution combustion (SC) reactions, their reduction including simultaneous structural transitions from the rhombohedral to the cubic phases, and subsequent reoxidations wh...

Toward Enhanced Oxygen Evolution on Perovskite Oxides Synthesized from Different Approaches: A Case Study of Ba0.5Sr0.5Co0.8Fe0.2O3−δ

Development of electrocatalysts for the oxygen evolution reaction (OER) plays a critical role in electrochemical water splitting systems. Perovskite oxides represent one category of efficient catalysts for the OER, among which Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) has been extensively studied. In this work, we discussed the effect of synthesis approaches on the OER performance of BSCF. Three routes, including solution combustion, sol-gel process and solid-state reaction, were applied to synthesize the bulk-sized BSCF perovskites, denoted as BSCF-SC, BSCF-SG and BSCF-SS, respectively. Electrochemical measurements revealed varied OER performance, with BSCF-SS showing the highest intrinsic activity much better than that of BSCF-SC and BSCF-SG. The activity difference may originate from the variation in the surface oxidation states of the B-site cobalt cations. Moreover, all the BSCF perovskites exhibited comparably good stability in catalyzing the OER. In light of the simplicity, the viability for scale-up and the high activity of BSCF-SS, solid-state reaction may be a suitable way for fabricating highly-active BSCF electrocatalyst. This study could provide new insight into enhanced oxygen evolution on perovskite oxides by selecting an optimized synthesis approach.

Energy transfer and tunable luminescence of Na2(Y,Eu)Mg2V3O12 phosphors for white LED applications

A series of solid-solution phosphors Na2(Y,Eu)Mg2V3O12 were prepared using solution combustion reaction. X-ray diffraction studies verified the formation of single phase Na2(Y,Eu)Mg2V3O12 with garnet structure. Na2(Y,Eu)Mg2V3O12 phosphors show not only a broad emission band with a maximum at 510nm due to the [VO4]3− group but also several sharp emission lines due to the Eu3+ ions. The energy transfer from [VO4]3− to Eu3+ was discussed on the base of the spectral analysis. The color-tunable emissions of the Na2(Y,Eu)Mg2V3O12 phosphor as a function of Y/Eu ratio are realized by continuously generating the varied hues from yellowish-green to reddish-orange. This indicates that the obtained phosphor may have potential applications in the field of UV-based white LEDs.

Visible upconversion luminescence of Yb co-doped Gd2Zr2O7:Er prepared by a solution combustion reaction

Phosphor powders of Gd2Zr2O7:Er3+ and Gd2Zr2O7:Er3+, Yb3+ have been prepared by the urea combustion route. Phase evolution of the synthesized powder is determined by X-ray diffraction techniques. Near infrared to visible frequency upconversion in the doped/codoped phosphors upon CW diode laser excitation at ~978 nm have been studied and an enhancement about ~26 and ~93 times in the green and red region observed in the Gd2Zr2O7:Er3+, Yb3+ compared to that of the Gd2Zr2O7:Er3+ phosphor. Based upon the ratio of green to red emission band and fluorescence intensity ratio, energy transfer from the Yb3+ to Er3+ ions has been observed to be a dominant process responsible for this enhancement in the visible region.

Solution combustion synthesis and enhanced luminescence of Eu3+-activated Y2Ce2O7 phosphor nanopowders

The rare earth Eu3+-activated yttria–ceria Y2Ce2O7 phosphor nanopowders were prepared by a rapid solution combustion reaction and subsequent sintering process. All the Eu3+-doped samples have cubic fluorite phase and exhibit predominant 5D0–7F2 transition emission when excited at 467nm, which are quite similar with that of Eu3+-doped CeO2. The average grain sizes of the composite are around 40nm, and almost all the particles are seriously melt together without the addition of surfactant. However, with the addition of certain amount of surfactant polyethylene glycol (PEG) in the combustion reaction, the well-dispersed particles with round shapes are obtained and the relative emission intensity of the samples is greatly enhanced. Under the same Eu doping concentration (0.15) and excitation wavelength (467nm), the relative emission intensity of the composite without the addition of PEG is almost 4-fold of Eu3+-doped CeO2. Assisted with PEG, the relative emission intensity of Eu3+-doped Y2Ce2O7 is further enhanced and reaches more than 6.5-fold as compared with Eu3+-doped CeO2. The improved particle morphology and enhanced emission intensity for Eu3+-activated Y2Ce2O7 phosphor nanopowders are quite beneficial for their applications in solid state lighting fields.

Nitrogen-Doping in ZnO via Combustion Synthesis?

We report the synthesis and characterization of colored ZnO-based powders via solution combustion reaction of urea and zinc nitrate hexahydrate in varying molar ratios between 1:1 and 10:1. Among other techniques, we employ X-ray diffraction, nuclear magnetic resonance, and Raman spectroscopy to characterize the products. Within a narrow range of reactant ratios, we reproducibly find an unidentified, crystalline precursor phase related to isocyanuric acid next to ZnO. Finally, we complement our investigations by performing Prompt Gamma Activation Analysis (PGAA) on selected products in order to directly determine elemental bulk compositions and compare these with X-ray photoelectron spectroscopy (XPS) measurements. Our data show traces of nitrogen mainly on the surface of the particles, and thus we question the solution combustion method as a reliable synthesis toward N-doped ZnO. Furthermore, we exclude nitrogen as being responsible for the appearance of the four controversially discussed Raman bands sup...

Characterization, Luminescence, and Defect Centers of a Ce3+-Doped Li2Si2O5 Phosphor Prepared by a Solution Combustion Reaction

Li2Si2O5 doped with Ce was synthesized by solution combustion. The phosphor was characterized by powder x-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). Photoluminescence was investigated by excitation with UV radiation at 244 nm. An emission peak of the Ce3+ ion was observed at 400 nm. Gamma irradiated phosphor exhibits six thermoluminescence (TL) peaks at 110°C, 160°C, 190°C, 250°C, 320°C, and 370°C. Electron spin resonance (ESR) spectroscopy was used to study the defect centers induced in the phosphor by gamma irradiation and to identify the centers responsible for the TL process. The room-temperature ESR spectrum of the irradiated phosphor seemed to be a superposition of at least four distinct centers. One of the centers (center I) with principal g values $$g_{\vert\vert}=2.0307$$ and g ⊥ = 2.0040 was identified as an O2 − ion. Center II, with an isotropic g factor 2.0070, was identified as an F+-type center (singly ionized oxygen vacancy); this center correlates with the main low-temperature TL peak at 110°C. Center III was identified as a Ti3+ center and center IV, with a hyperfine interaction with a 29Si nucleus, as an intrinsic O−-type center with a neighboring silicon ion. A Ti4+ion, the precursor of the Ti3+ center, acts as a recombination center for the 110°C TL peak whereas a Ti3+ center relates to the main 250°C TL peak and is also the likely recombination center for this peak. An O− ion is associated with the 110°C TL peak as a possible recombination center. An additional defect center (V) was observed during thermal annealing experiments. This center (identified as an F+ center) seems to originate from an F center (oxygen vacancy with two electrons) and is not related to the any of the observed TL peaks.