Low-temperature Combustion Method Research Articles

Structural Elucidation, IR spectroscopy and DC electrical conductivity of Ni0.6Zn0.4GdyFe2-yO4 nanoferrites synthesized via a low-temperature citrate gel combustion method

In the present work, we report the detailed Powder XRD Rietveld refinement and elucidation of structural factors of Ni0.6Zn0.4GdyFe2-yO4 nanoferrites. The Ni0.6Zn0.4GdyFe2-yO4 nanoferrites synthesized via low-temperature citrate gel combustion technique for the various levels of Gd3+ ion concentration (y = 0.0, 0.1, 0.15 and 0.20). The generated structural factors signify the dependence on the concentration of Gd3+ ions. The prepared samples were found to crystallize in the Fd-3m space group and also identified their occupancies; some of the Fe3+ ions of the octahedral site at the 16d position will be replaced by Gd3+ ions. The lattice constant and crystallite size dropped to a low value for y = 0.1, and then, later, noticed the small increment. The crystallite sizes of the sample are to fall in the range of 26.1 nm–37.6 nm. The cation distribution among the tetrahedral (AII) and octahedral sites (BII) has been estimated. The obtained values correlate with Gd3+ ion concentration, and the radius variation of AII and BII sites signifies the migration of Fe3+ ions from the BII site to the AII sites. The force constant of Metal-Oxygen bonds was determined from the infrared spectrographs; the force constant was found to be relatively low with the BII site. The DC electrical conductivity infers the semiconducting nature and distinct phase of conductivity, which is attributed to the magnetic phase change due to temperature. The magnetic curie temperatures of the sample are obtained by the Arrhenius plot, which signifies the dependence of Gd3+ion concentration.

JO parameter analysis for Y2O3: Eu3+nanophophor synthesis by novel low temperature combustion method with thioglycerol as fuel for near UV light emitting diode

JO parameter analysis for Y2O3: Eu3+nanophophor synthesis by novel low temperature combustion method with thioglycerol as fuel for near UV light emitting diode

Study on synthesis and properties of Na+–La3+ co-doped γ-Ce2S3 pigment by low-temperature self-propagating combustion method

Study on synthesis and properties of Na+–La3+ co-doped γ-Ce2S3 pigment by low-temperature self-propagating combustion method

Rapid nitrophenol degradation using gel-combustion synthesized nickel/manganese cobaltite (Ni1−xMnxCo2O4) nanoparticles

Developing efficient catalysts is one of the challenging tasks for protecting our environment from contamination. Here we present the synthesis of Ni1−xMnxCo2O4, noble-metal free multimetallic oxide nanoparticles of 9.5–25.0 nm average sizes by a low-temperature gel combustion method and their utilization as catalysts for rapid reduction of 4-nitrophenol (4-NP) to aminophenol (AP). Scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and vibrating sample magnetometry were used for the characterization of the nanostructures. All the nanostructures revealed strong catalytic performance in the reduction of 4-NP, and the performance of Ni0.5Mn0.5Co2O4 nanoparticles was superior (>90 % reduction in 12 min) to that of NiCo2O4 and MnCo2O4 nanoparticles. While the 4-NP reduction process followed a pseudo-first-order kinetics for all the catalysts, the reduction efficiency of the samples manifested a complex trend from cycle to cycle. The anomalous catalytic behavior of the nanostructures in 4-NP degradation has been explained.

Enhanced high-rate performance in Zn/Al dual-doped LiMn2O4 with submicron truncated structure

The Jahn-Teller effect and Mn dissolution always restrict the practical electrochemical properties of spinel LiMn2O4 cathode material. Herein, a low-temperature solid-state combustion method is employed to synthesize various truncated octahedral LiZn0.03AlxMn1.97-xO4 (x ≤ 0.08) with submicron structure. The Zn/Al dual-doping is conducive to forming {110} and {100} planes, and is also beneficial to the crystal development of LiMn2O4. It is found that as the amount of Al doping increases, the average particle size gradually decreases from 188 nm to 113 nm. In addition, the Zn/Al co-doping integrated with small particles can improve the high-rate performance. The optimal LiZn0.03Al0.03Mn1.94O4 exhibits submicron truncated octahedral morphology, high crystallinity, and good particles dispersibility. Benefiting from these structure merits, the LiZn0.03Al0.03Mn1.94O4 delivers the first discharge capacity of 113.1 mAh⋅g−1 and low capacity fade of 9.9 % after 300 cycles at 1C. It also shows the high first discharge capacity of 86.6 mAh⋅g−1 at 10C and the high capacity retention of 72.1 % after 2000 cycles. Even at ultrahigh current density of 15C and 20C, the ultralong cycling lifespans over 2000 cycles are also achieved in LiZn0.03Al0.03Mn1.94O4 cathode material. The excellent electrochemical properties are ascribed to its relatively high Li+ diffusion coefficient (1.60 × 10−11 cm2⋅s−1) and low apparent activation energy (25.45 kJ⋅mol−1) during the de-intercalation process. The Zn/Al dual-doping and submicron truncated octahedron designs of the LiMn2O4 provide a scientific reference to prepare high-performance cathode materials.

Anti-counterfeiting and multifunctional applications of near white emitting La1.99MgTiO6:0.01Dy perovskite nano phosphors

A 1 wt% dysprosium doped double perovskite nano phosphor La2MgTiO6 is synthesised by a low-temperature combustion method. When excited with UV radiation (351 nm), the sample shows major characteristic emission peaks at 480 nm (4F9/2 →6H15/2) and 574 nm (4F9/2 →6H13/2) whereas, when excited by IR radiation (980 nm), an up-conversion emission peak at 654 nm (4F9/2 →6H11/2) is observed. The photoluminescence spectra of La1.99Dy0.01MgTiO6 show dominant blue emission, which obliges potential white LED applications with chroma coordinates (0.32, 0.33). On the other side, the samples annealed above 1223 K build suitable reading light that shows dominant yellow emission with a quantum efficiency of 69.25 %; which simplifies why samples with high-temperature heat treatment are pertinent yellow-emitting phosphor. Using the Tauc plot, an improvement of ΔEg= 14 meV is seen owing to annealing at 1223 K. The XRD, Raman, SEM, and TEM results signify the increase in crystallinity and crystallite size with annealing. Noticeably, the red emission upon up-conversion highlights the medical imaging purpose. The effective combination of up-down conversion emission can be successfully exploited for anti-counterfeiting applications; underlining the multifunctional application of a single perovskite nano phosphor for smart materials.

Near-infrared photo-responsive Er3+-K+ co-doped Y2O3 phosphors with enhanced UC luminescence

Y2O3: x% Er3+ (x=5, 7, 10, 12, 15) and Y2O3: 10% Er3+，x% K+ (x=0, 1, 3, 5, 7, 10, 15) phosphors were successfully prepared by a low-temperature combustion method. The structure as well as the absorption/emission spectra of phosphors were investigated. The effect of doping concentration of K+ ions on the upconversion (UC) luminescence of Y2O3: 10% Er3+ phosphor was examined and the possible optical transitions were discussed. The results showed that K+ ion doping not only changed the microstructure and crystallinity of the phosphors, but also enhanced its UC luminescence intensity. The Y2O3: 10% Er3+, 7% K+ phosphor exhibit the strongest UC emission intensity. Compared with the Y2O3: 10% Er3+ phosphor, the UC luminescence intensity at 563 nm and 661 nm was enhanced by 67.8 and 27.3 times for the K-codoped samples, respectively. The phosphor with the optimal doping concentration was mixed with a polymer to form a composite film, which was employed for the fabrication of near-infrared (NIR) photo-responsive detection devices. The device exhibited strong photo-current response to NIR light at 980 nm, implying that our work could inspire new design strategy for the development of NIR photo-detection devices.

Intensity enhancement of photoluminescence in Tb3+ /Eu3+ co-doped Ca14 Zn6 Al10 O35 phosphor for WLEDs.

This article focuses on the effect of monovalent cation doping on the optical properties of rare earth (RE = Eu3+ , Tb3+ ) co-doped Ca14 Zn6 Al10 O35 which has been synthesized by a low temperature combustion method. Crystalline phase of the Ca14 Zn6 Al10 O35 phosphor was examined and confirmed by X-ray diffraction measurement. Under near-ultraviolet light excitation Eu3+ -doped Ca14 Zn6 Al10 O35 phosphor exhibit characterization of Eu3+ emission bands that are located at a maximum wavelength (λmax ) of approximately 470 nm and other peaks centred at 593 nm and 615 nm, respectively. With Tb3+ -doped Ca14 Zn6 Al10 O35 phosphor showing a green emission band centred at 544 nm under near-ultraviolet range. Furthermore, we studied the energy transfer process in Eu3+ /Tb3+ pair and enhancement in photoluminescence (PL) intensity with doping different charge compensation. Here we obtained the optimum PL emission intensity of the phosphor in broad and intense visible spectral range which may be significant for the fabrication of white light emitting diodes (WLEDs).

Co-doping of Ho-Yb ion pairs modulating the up-conversion luminescence properties of fluoride phosphors under 1550 nm excitation.

In this study, up-conversion fluoride phosphors NaY1-x-y-m-nMxF4:Er3+y,Ho3+m,Yb3+n (M = Lu3+/Gd3+) were synthesized by a low-temperature combustion method. The optimal ionic ratios in the matrix lattice were also determined by a controlled variable method. It was confirmed that doping a small amount of Ho3+ ions and Yb3+ ions in the Er-doped sample matrix lattice can form a mutual sensitizer and a transient energy capture center to enhance the sample's up-conversion luminescence under excitation at the 1550 nm band, respectively. It was also found that the lanthanide ion introduced can modulate the red-to-green ratio of the up-conversion luminescence of the sample. The phase composition and morphology of phosphors were investigated using X-ray diffraction and scanning electron microscopy. The up-conversion luminescence mechanism of Er-Ho-Yb tri-doped samples excited at the 1550 nm band was also investigated. This work presents a novel approach for improving up-conversion luminescence with high color-purity phosphors for display lighting applications when excited at 1550 nm.

Thermoluminescence response and trap features of gamma-irradiated Sr2Al2SiO7:Dy3+ phosphors

This study mainly focuses on the thermoluminescence features and trap parameter analysis of Sr2Al2SiO7:Dy3+ phosphors prepared via the low-temperature combustion method. The phase confirmation, structural and morphological studies are performed using XRD, FTIR, SEM and EDX characterizations. The energy gap of pure and Dy3+ doped phosphors is calculated. And the band gap decrease with doping. The optimum concentration was 3 mol% from the emission spectra; hence, this sample was irradiated with 3 Gy–5 kGy gamma doses. The samples showed high sensitivity and the MDD value is 0.21 mGy. The trap parameters were determined following deconvolution of the glow curves. Four traps were found in the samples, and the trap lifetime increased with increasing gamma dose. The trap depth increased The linear response from 3 Gy to 250 Gy implies that the prepared samples could be used as γ dosimeters within this range.

Synthesis of CTAB modified ferrite composite for the efficient removal of brilliant green dye

ABSTRACT In the present work, magnetic nickel ferrite (NiFe2O4) have been synthesised using low temperature combustion method and then modified with Cetyltrimethylammonium bromide (CTAB) to form a magnetic composite. Prepared composite (CTAB-NiFe2O4) was used as an adsorbent for removing brilliant green dye from aqueous solution. Adsorbent was investigated by using various techniques like Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, energy-dispersive spectra, thermogravimetric analysis and pH of point zero charge. Different parameters such as effect of contact time, pH, adsorbent dose and initial dye concentration were studied for the adsorption of dye. The optimum values observed were 170 minutes equilibrium time at pH 6 and adsorbent dose 0.6 g. Various adsorption kinetic models such as pseudo first-order kinetic model, pseudo second-order kinetic model and Elovich model were used to determine the nature of adsorption. Pseudo second-order kinetic model fitted better with higher R2 value which indicated that the adsorption was chemical in nature. Langmuir isotherm was best fitted to experimental data for the adsorption of brilliant green dye with maximum adsorption capacity ‘Qe’ 250 mg/g. It revealed that the adsorption in this study takes place on homogenous surface and follows monolayer pattern. Therefore, for the removal of Brilliant green dye from wastewater using composite (CTAB-NiFe2O4) can be considered as an effective adsorbent.

Performance study on the C.I engine using LHR and LTC in combination with biodiesel blends

Currently, the research of a single-cylinder 4-stroke direct injection diesel engine, which was naturally aspired, was used, and two modification methods were used. The first is the low-heat rejection method (LHR), and the second is the low-temperature combustion method (LTC). LHR was introduced into the engine by ceramic coating with alumina, which is applied to engine components such as the piston, cylinder lining, and valves and has a thickness of 300 microns without affecting the dimensions of the engine parts. In the next method, low - temperature combustion (LTC) method is done with EGR technique. And the exhaust gas recirculation setting (EGR) is included in the same setup as that of first method. Since, 15% of an exhaust gas is used in the EGR process. The diesel is blended with 20% of mahua biodiesel and 5% of ethanol as a fuel. After that, the engine performance is tested with conventional fuel when compared with biodiesel as a combined LHR and LTC methods. Finally, the engine output is increased by up to 3.48% as a result of the combination of LHR and LTC. As a result, emission levels could be dramatically decreased, and other results obtained could include a decrease in infrared radiation, resulting in a decrease in specific fuel consumption (SFC), and a substantial improvement in engine efficiency characteristics.

Transformation of Phosphorus during Low-Temperature Co-Combustion of Sewage Sludge with Biowastes

Thermal treatments of phosphorus (P)-rich sewage sludge for efficient P reclamation have recently gained much attention. Our recent research proposed a low-temperature combustion method that can si...

Probing defects and electronic structure of Eu doped t-Mg2B2O5 nanocrystals using X-ray absorption near edge spectroscopy and luminescence techniques

We report here the defects and electronic structure study of Eu (1%,3%,5%) doped t-Mg2B2O5 nanocrystals synthesized using low temperature combustion method, and probed using x-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray absorption near edge spectra (XANES), photoluminescence (PL) and thermoluminescence (TL). The XRD analysis of all samples shows single phase triclinic crystal structure and average crystallite size decreases with Eu doping in Mg2B2O5. The experimental XANES spectra of each sample acquired at Eu M5,4-edges were compared with simulated absorption edges using atomic-multiplet calculations, which clearly shows the presence of Eu3+ in Mg2B2O5. The O K-edge spectra of Eu doped Mg2B2O5 predicts the formation of O and Mg defects upon increasing Eu concentrations. The photoluminescence of Mg2-xEuxB2O5 nanocrystals at an excitation of 325 nm comprises of a group of sharp peaks owing to intra-4f transitions in Eu3+ and confirms the lowering of local symmetry with Eu concentration in Mg2B2O5. The effect of Eu doping on the trapping states was probed using TL after irradiating Mg2B2O5 with ultra-violet radiations (365 nm), which shows the presence of shallow and deep level trapping states. The corresponding activation energies of trapping states were determined using glow curve deconvolution method based on Kitti's general order equation.

Photocatalytic Activities, Kinetics and Adsorption Isotherm Studies of CeO2 Nanoparticles Synthesized via Low Temperature Combustion Method

Background:We synthesized cerium oxide (CeO2) nanoparticles (NPs) via green synthesis method mediated with Rajma seeds powder as a fuel and cerium nitrate as an oxidizer.Objective:The obtained cerium oxide nanoparticles are used to study the various environ mental appilications.Methods:The achieved CeO2 nanoparticles are tested using PXRD (Powder X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), electron microscopic studies including SEM, Raman spectroscopy, UV-Visible spectroscopy. Formation of agglomerated cubic phased CeO2 nanoparticles were confirmed from both PXRD and SEM.Results:The average crystallite size of CeO2 nanoparticles was found to be 38 nm calculated from highly intense peak using Debye-Scherer’s formula. The characteristic Ce-O stretching was confirmed by FTIR and Raman studies. CeO2 nanoparticles are promising material for the organic dye degradation. Photocatalytic activities evaluation under various parameters like sunlight, UV light and variation of PH, catalytic dosage etc. CeO2 nanoparticles exhibit highly enhanced photo degradation of Methylene Blue dye. Kinetics and isotherm models of Photocatalysis were studied.Conclusion:We have prepared CeO2 nanoparticles by low-temperature combustion technique using Rajma germinated and Rajma non- germinated seeds as fuel. The XRD pattern confirms the formation of cubicphase CeO2 nanoparticles. The existence of Ce-O vibration is confirmed by FTIR and Raman spectra of the CeO2 nanoparticles. The UV-Visible spectra of CeO2 nanoparticles reveal the absorbance band range at 350-390 nm. SEM images of CeO2 nanoparticles indicates the agglomerated with irregular morphology. CeO2 nanoparticles are favorable material for the organic Methylene blue dye degradation. The different amount of the Rajma influences improved Photodegradation of cerium oxide nanoparticles was characteristics of slight crystal dimension, new superficial deficiencies, more band hole and ability to make smaller the electron-hole pair rearrangement. Adsorption kinetics results show that adsorption of MB over cerium oxide follows pseudo-first-order and second-order kinetics. Using the Langmuir isotherm, Freundlich isotherm, maximum adsorption capacity is calculated. Thus it can be used as attractively recoverable nano adsorbent for the removal of MB dye by adsorption technique from effluent water.

Study on Sinterability of Magnesium Aluminate Spinel Powders Prepared by Different Technologies

In this paper, the phase, structure and sinterability of magnesium aluminate spinel powders prepared by the chemical co-precipitation, low temperature combustion and solid phase reaction methods were studied. The results show that the uniform nanometer magnesium aluminate spinel powders are prepared from precursor via the chemical co-precipitation, calcined at 700°C. Using the low temperature combustion method, the agglomeration, complete crystalline nanometer magnesium aluminate spinel powders are prepared at the thermal explosion temperature of 400°C. For the magnesium aluminate spinel micrometre powders synthesized by the solid phase reaction method, the phases are mainly spinel with a little of periclase and corundum phase. The sinterability of powders prepared by chemical co-precipitation method is the best, but that of powders synthesized by low temperature combustion and solid phase reaction methods are poor.

High-quality NiO thin film by low-temperature spray combustion method for perovskite solar cells

As a potential hole transport material for perovskite solar cells, nickel oxide presents attractive properties in stability and price. However, in most cases, NiO thin films are prepared in high temperature, which is not suitable for the wide application of perovskite solar cells. In this work, we proposed to fabricate NiO thin films at relatively low temperature by spray combustion method, which performed better than that by spin-coating method. The optimal ratio of nickel nitrate to acetylacetone, combustion induced temperature, and spraying volume of precursor were completely investigated. Based on these conditions, we obtained a uniform and dense NiO thin film with proper thickness, which were further employed as hole transport film for invert perovskite solar cell. A highest efficiency of 12.7% was achieved for perovskite solar cells. Moreover, a stable current output at 0.8 V in 300 s was observed in the best-performing perovskite solar cell. In a word, this work demonstrated a facial method to get NiO thin film in low temperature which was good for the further research of perovskite solar cells.

A low-temperature-annealed and UV-ozone-enhanced combustion derived nickel oxide hole injection layer for flexible quantum dot light-emitting diodes.

Sol-gel derived nickel oxide (NiOx) has been extensively investigated as the hole injection layer (HIL) for many optoelectronic devices because of its advantages of high environmental stability and low cost fabrication. Conventional sol-gel synthesis of NiOx requires high annealing temperature to convert precursors into crystal lattices, which limits its application in flexible devices. To address this issue, a low-temperature (150 °C) combustion method is used to synthesize NiOx. Besides, UV-ozone treatment is further performed to improve the electrical properties of low-temperature-grown NiOx, which leads to the formation of nickel oxyhydroxide (NiO(OH)) surface dipoles and Ni vacancies and thus modifies the energy structure and increases the conductivity of NiOx. Moreover, the formation of surface NiO(OH) induces a vacuum level shift and thus reduces the hole injection barrier. Owing to the enhanced hole injection, solution-processed green QLEDs with optimized UV-ozone treated NiOx HILs exhibit maximum current efficiencies of 45.8 cd A-1 and external quantum efficiencies of 10.9%, which outperform those of the devices with poly(3,4-ethylene dioxythiophene) : poly(4-styrenesulfonate) (PEDOT:PSS) HILs. Meanwhile, these devices also show better long-term stability with a 3.2-fold longer half-life time than that of the PEDOT:PSS-based devices. The demonstrated low-temperature-annealed and UV-ozone enhanced NiOx HILs would enable the realization of flexible QLEDs with high brightness, efficiency and stability.

Improved utilization of phosphorous from sewage sludge (as Fertilizer) after treatment by Low-Temperature combustion

The utilization of phosphorus from sewage sludge is an important method used to solve the shortage of phosphorus resources in the world. However, high levels of toxic compounds and low phosphorus bioavailability in sewage sludge are the main factors limiting its direct agricultural use. This paper proposes a low-temperature combustion method that can enrich the phosphorus in sludge ash. Low temperature-treated sewage sludge ash (LTSA) at different oxygen concentrations (20%, 60%, 100%) were obtained through a specific experimental device. Then, the species and leaching characteristics of phosphorus in LTSAs were analyzed and compared with pyrolysis sewage sludge char (PSSC) and incinerated sewage sludge ash (ISSA). Results show that low-temperature combustion of sludge increased the total phosphorus content in the bottom ash by 45.6%, and the bioavailable phosphorus content increased 2.9 times. Further, by increasing the concentration of oxygen while carrying out low-temperature combustion of sludge, part of the non-apatite inorganic P was converted to apatite P (AP), resulting in a 46.3% increase in AP in the sludge. Low-temperature combustion can also convert heavy metals (Cd, Cr, Cu, Pb, and Zn) in the sludge from an easily leachable form (acid extractable fraction and reducible fraction) to a stable form (reducible fraction) and decrease the leaching of heavy metals. Leaching of Cr and Cu decreased by 97.56% and 98.52%, respectively.

Effects of a psychological intervention on glycemic control and psychological distress in individuals with type 2 diabetes

Tm3+ and Dy3+ co-doped Ba0.05Sr0.95WO4 phosphors were synthesized by a low temperature combustion method. The structures of the samples were SrWO4 phase and were identified by X-ray diffraction. The surface topographies of Ba0.05Sr0.91WO4:0.01Tm3+ 0.03Dy3+ were tested by scanning electron microscopy. The particles are ellipsoid, and their average diameter is approximately 0.5 μm. The emission spectra of Ba0.05Sr0.95WO4:Tm3+ show a peak at 454 nm which belongs to the 3H6→1D2 transition of Tm3+, and the optimum doping concentration of Tm3+ ions was 0.01. The emission spectra of Ba0.05Sr0.95WO4:Dy3+ consist of the 4F9/2 → 6H13/2 dominant transition located at 573 nm, the weaker 4F9/2 → 6H15/2 transition located at 478 and 485 nm, and the weakest 4F9/2 → 6H11/2 transition located at 660 nm, and the optimum doping concentration of Dy3+ ions was 0.05. A white light is achieved from Tm3+ and Dy3+ co-doped Ba0.05Sr0.95MoO4 crystals excited at 352–366 nm. With the doping concentration of Tm3+ fixed at 0.01, the luminescence of Ba0.05Sr0.95MoO4:Tm3+ Dy3+ is closest to standard white-light emissions when the concentration of Dy3+ is 0.03; the chromaticity coordinates are (0.321, 0.347), and the color temperature is 6000 K.