Combustion Method Research Articles

Customizing hetero-structured high-entropy alloy/oxide active site by regulating the exsolution strategy for highly efficient water splitting

Transition metals and their oxide materials are crucial in promoting hydrogen production efficiency via water splitting. However, the sluggish reaction kinetics of the oxygen evolution reaction (OER) process at the anode requires synergy between multiple active sites for effective activation and high electrocatalytic performance. In this study, an atomic contacted hetero-structured catalyst between high-entropy alloy (HEA) and high-entropy oxide (HEO) was synthesized for realizing highly active and robust OER. The heterogenous HEA/HEO catalyst was prepared by thermal reduction of the rock-salt HEO oxide of (NiCoFeCuAl)O, grown in situ on Ni foam via a fast self-propagating combustion method. The exsolution of face-centered cubic (FCC) structured NiCoFeCu HEA from the NiCoFeCuAlO matrix is beneficial for establishing a strong electron-transferring effect and providing more active reaction sites. Using combined actions of HEA/HEO heterointerfaces and nanoporous structure, the optimized catalyst (R-SNCFCA4.5) displays excellent OER performance with overpotential of 228 mV at current density of 10 mA cm−2, respectively, exhibiting a Tafel slope of 80.52 mV dec−1, and a 2.8 % decay activity for 100 h in alkaline medium. The R-SNCFCA6 catalyst with high extent exsolution of NiCoFeCu showcases the optimal HER performance. We reported the successful construction of HEA/HEO heterogeneous catalysts and demonstrated their application towards a highly efficient water splitting process.

IR reflective performance of ZnO: Dy pigment on glass surface

In this paper, we have discussed the heat reflective properties of ZnO: Dy3+ pigment synthesized by the combustion method and co-precipitation method. The phase purity and crystalline nature of the prepared pigment have been studied using XRD and SEM. The IR-reflective properties of the pigment DRS have been measured. A paint formulation of the ZnO: Dy3+ pigment was prepared in alkyd resin. The performance of the heat-reflective paint has been investigated by coating the glass surface. From the present investigation, it is seen that the prepared ZnO: Dy3+ pigment is well suited to increase the IR reflectance to cool the surface.

Role of Fe and Cr doped ZnO nanoparticles for electrocatalytic oxygen evolution reaction

Developing highly efficient catalysts for oxygen evolution reactions using abundant earth-rich and non-precious metals poses a critical and indispensable challenge. In this study, Fe: 1, 3, and 5% and Cr: 2% doped ZnO nanoparticles (NPs) were synthesized by employing a simple solution combustion method (SCM) for oxygen evaluation reaction (OER). Using a variety of methods, the synthesized transition metal-doped metal oxides were thoroughly examined. The electrochemical behavior of the Fe and Cr-doped ZnO electrodes in an alkaline solution was investigated through LSV, EIS, CV, and CA. The electrochemical studies showed that ZnO/Cr/Fe:5 (η = 305 mV and Tafel slop = 46 mV/dec) demonstrates significant oxygen evolution reaction (OER) activity under alkaline conditions. All prepared samples exhibit good stabilities for up to 10 h.

Structural, morphological, and optical investigations of Mn-doped LaAlO3 perovskite obtained by microwave-assisted combustion and rapid calcination at low temperature

In this work, LaAlO3 perovskite was doped with 1, 2, 3, 5, 8, and 13 mol% of Mn using the microwave-assisted combustion method. The powders produced were heat treated at 700 °C and 900 °C for 10 min in an adapted microwave oven and then characterized by Thermogravimetric analysis (TG/DTG) and Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD) and Rietveld refinement, X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR), Raman, Ultraviolet–Visible Reflectance (UV–Vis), Field Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive X-ray Spectroscopy (EDS). The materials produced doped with the highest concentration of Mn (13 %) showed a single-phase reduced crystallite size compared to the pure sample. The unit cell volumes increased compared to the pure material, while the oxidation state of the dopant was mainly Mn3+. The refinement data for the volume of the different polyhedral that comprise the LaAlO3 unit cell revealed a local change at both sites, which may also indicate Mn substitution at the A site. The heat treatment temperature did not change significantly, demonstrating the method's efficiency in producing perovskites at temperatures and times below those reported in the literature. The morphology observed was porous and irregular agglomerates, and the bandgap was 2.90 eV.

Production, by the sol-gel combustion method, of superparamagnetic particles at room temperature

Production, by the sol-gel combustion method, of superparamagnetic particles at room temperature

Optimizing diesel engine performance and emissions with diesel-hydrogen mixtures: Impact of injector configuration, angle, and pressure

Several factors affect engine performance, including fuel injection pressure, injection angle, and injector orifice diameter. Any deviation from normal conditions in any of these aspects can disrupt optimal engine performance, resulting in inefficient combustion and increased exhaust emissions. To investigate the effect of injector hole number, injection hole angle, and injection pressure on the performance and emissions of a diesel engine operating on a diesel/hydrogen blend (10 % hydrogen and 90 % diesel), a single-cylinder direct injection diesel engine was used. Three injector nozzle configurations just for diesel injector with different hole diameters (0.6, 0.3, and 0.2 mm) were used at injection angles of 0, 15, and 30 degrees, respectively. Three injection pressures (200, 400, and 600 bar) were tested, with results monitored for brake-specific fuel consumption (BSFC), brake thermal efficiency (BTE), smoke, and NOx emissions.Optimal results were achieved with a maximum injection pressure of 400 bar and a nozzle angle of 15 degrees, resulting in improved engine performance and BTE, along with a 6.5 % reduction in BSFC. Increasing the number of injector holes, injection pressure, and injection angle resulted in reduced BSFC and smoke emissions, but with a significant increase in NOx emissions. Notably, this study deviates from traditional combustion methods by introducing air from a 1.1-atmosphere tank instead of relying solely on natural intake. In addition, hydrogen fuel is introduced into the air manifold via a separate injector with an injection pressure of 20 bar, while diesel fuel is injected directly into the combustion chamber.

Manganese doped La0.8Ba0.2FeO3 perovskite oxide as an efficient electrode material for supercapacitor

In this study, L0.8Ba0.2Fe1-xMnxO3 (LBFM-x, x = 0.0, 0.2, 0.5, 0.8) perovskite materials were synthesized by a Sol-Gel combustion method and were investigated as an electrode material for a supercapacitor device. The morphology, crystalline structure and electrochemical performance of the samples were studied in detail. The active points, where the electrochemical redox reaction takes place to store faradaic energy, are the oxygen vacancies on the surface of perovskite oxides. Partial substitution in the B-site of the perovskite structure, which is directly related to the oxygen vacancy in BO6 octahedral, is effective in optimizing the electrochemical performance. Based on the results of structural analysis, LBFM-0.2 has the highest concentration of oxygen vacancies; thus, it showed a higher electrochemical performance compared to other samples. The supercapacitors prepared with this electrode material should have an acceptably high specific capacitance of 685 F.g−1 at a current density of 2.0 A.g−1. The partial substitution of Mnn+ at the B-site increases the oxidation state of Fe cations and the mobility of oxygen ions through the oxygen vacancy sites. The electrochemical stability of LBFM-0.2, was evaluated by applying long charge-discharge cycles. After 3000 charge-discharge cycles, the supercapacitor was able to maintain about 94 % of its initial capacity.

Super capacitive electrode performance analysis of facile synthesized α-Fe2O3 aerogel and its nanocomposite with in-situ formed polyaniline (α-Fe2O3/PANI)

This paper presents the synthesis of an α-Fe2O3-assisted polyaniline (α-Fe2O3/PANI) nanocomposite using a straightforward two-step process. Initially, α-Fe2O3 aerogels with cratered nanohexagon structures are synthesized through a solution combustion method assisted by noni (Morinda citrifolia) fruit extract. In the second step, these nanohexagons facilitate the preparation of α-Fe2O3/PANI via in-situ chemical oxidative polymerization of anilinium chloride. The structural, optical, and morphological properties were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDAX). Electrical conductivity, wettability, and electrochemical properties of the prepared materials were assessed. The results indicate that the 2D cratered α-Fe2O3 aerogel is effectively embedded within PANI, forming a modified nano α-Fe2O3/PANI composite. The composite exhibited altered DC conductivity and electrolyte wettability. After 200 cycles of cyclic voltammetry (CV), the specific capacitance of the nano α-Fe2O3/PANI was determined to be 153 Fg⁻¹ at a scan rate of 10 mVs⁻¹, retaining approximately 90 % of its cycle stability. Electrochemical impedance spectroscopy (EIS) revealed significantly lower charge transfer and equivalent series resistance values for the nano α-Fe2O3/PANI electrode compared to the pure α-Fe2O3-based electrode. Galvanostatic charge-discharge (GCD) tests further demonstrated the superior electrochemical performance of the α-Fe2O3/PANI nanocomposite electrode. Therefore, this α-Fe2O3/PANI is an advanced conducting polymeric electrode for electrochemical applications.

Bi3+ doped nanocrystalline Ni–Co–Zn spinel ferrites: Tuning of physical, electrical, dielectric and magnetic properties for advanced spintronics applications

This study reports the synthesis and characterization of nanocrystalline Ni0.5Co0.2Zn0.3BixFe2-xO4 (x = 0.00, 0.025, 0.050, 0.075, 0.100) ferrites synthesized via the sol-gel auto combustion method. The structural, morphological, electric, dielectric, and magnetic properties of Bi3+-doped Ni–Co–Zn spinel ferrites annealed at 700 °C and further sintered at 850 °C, have been investigated towards analyzing the effect of Bi3+ doping. X-ray diffraction (XRD) patterns and Fourier Transform Infrared Spectroscopy (FTIR) spectra have revealed the single-phase cubic-spinel structure of all inspected materials while retaining their high crystalline nature. Their average crystallite size and average grain size are found in the nanoscale range (48–74 nm) and (46–67 nm), respectively. The saturation magnetization (Ms) and experimental magnetic moment (ηexp) are found to decrease with increasing Bi3+ content. The samples sintered at 850 °C display higher AC resistivity, attributing to the reduction of electrons hopping through grains in the samples. The low coercivity values (23.68–87.71 Oe) are observed, classifying the investigated materials as soft ferromagnetic. The increased magnetic anisotropy (K) through Bi3+ doping indicates tunable stability in magnetic orientations, making them suitable for spintronics applications.

Structural, Optical and Humidity Sensing performance of Lanthanum doped CoCr2O4 nano-ceramics for Sensor Applications

In the present study, we have investigated the influence of Lanthanum doping concentration on the structural, microstructural, dielectric, and humidity sensing performance of rare earth Lanthanum cobalt chromite nanoparticles. These nanomaterials were synthesized by the solution combustion method using glucose and urea as fuels. Structural investigations revealed that the synthesized materials are single-phase, highly crystalline, and porous, with spherical agglomerated nanoparticles of crystallite size ranging from 13 nm to 17 nm. Particle size distribution and pore area distribution were plotted using imageJ software. Energy dispersive spectroscopy confirmed the accurate elemental composition of all samples, consistent with the calculated stoichiometry. Optical absorption studies showed a blue shift in the peak as the doping concentration increased, indicating a quantum confinement effect. Dielectric constant and electrical resistivity measurements ensured that the materials are electrically conducting, which is necessary for humidity sensing applications. Humidity sensing measurements demonstrated that the capacitive humidity sensitivity coefficient (SC) and resistive humidity sensitivity coefficient (SR) were highest for the La (0.05) sample. The XPS survey spectra and high-resolution core-level spectra provide a thorough understanding of the elemental composition, oxidation states, and electronic environments in La-doped cobalt chromite nanoparticles. This detailed analysis is critical for tailoring the material's properties for specific applications in catalysis, electronics, and magnetic devices.

TL, EPR, and optical properties of undoped and Eu-, Ce-, Tb-, Sm-, Cu-, Mn-, and Li- doped MgSiO3 phosphors, synthesized by sol-gel combustion technique

Polycrystalline MgSiO3 samples, undoped or doped with rare earth- (Eu, Tb, Ce, Li, Sm), transition- (Mn and Cu), and alkali metal- (Li) elements, were prepared by the sol-gel combustion method and characterized by thermoluminescence, electron spin resonance, and optical properties. Enstatite and protoenstatite phases are observed in undoped and doped MgSiO3. Better TL results have been observed for phosphors doped with Tb, Ce, and Li (0.5 % mol). Fading experiments and the GCD method have been performed. EPR signals of gamma-irradiated phosphors indicate the formation of radiation-induced defect centers. Cu-doped MgSiO3 shows an unusual feature of the Cu2+ ion. The Cu2+ ion occupies a tetragonally compressed octahedral site, presenting an unconventional attribute. Optical bandgap value Eg is higher for the Ce, Tb, Mn, Li, Sm, and Cu-doped MgSiO3 phosphors. Ce, Li, and Tb dopant ions were found suitable for the MgSiO3 sample regarding its thermoluminescent response and its possible application in radiation dosimetry.

Optimization and luminescence studies of Sm3+ doped LiCaBO3 phosphors for high-performance white light-emitting diodes

An undoped and a series of orange-red emitting LiCaBO3:Sm3+ (x = 0.5–3 mol%) phosphors have been synthesized using a highly reliable and cost-effective combustion method. The synthesized phosphors were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), photoluminescence spectroscopy (PL), and Diffuse Reflectance spectroscopy (DRS). The structural studies of the LiCaBO3:Sm3+phosphor confirm the single-phase orthorhombic structure with space group Pbca and the presence of borate anionic groups. Upon near-UV excitation at 405 nm, the PL emission spectra show four emission peaks centered at 564 nm, 602 nm, 650 nm, and 708 nm corresponding to the 4G5/2 → 6H5/2, 4G5/2 → 6H7/2, 4G5/2 → 6H9/2 and 4G5/2 → 6H11/2 transitions respectively resulting in the emission of orange-red light. The optimum dopant concentration of Sm3+ion was 1 mol% and the main mechanism of concentration quenching was calculated using Dexter's theory. The bandgap of the undoped phosphor was found to be 5.31 eV. The CIE chromaticity coordinates are (0.56, 0.40) which confirms the orange-red emission. The obtained results indicate that the synthesized phosphor can be a potential candidate for application in solid-state lighting devices.

Preparation and Study Some Properties of Ferrite Nanoparticles(CuxAl0.3-xNi0.7Fe2O4)

The current study includes the preparation of CuxAl0.3-xNi0.7Fe2O4 ferrite nanoparticles where: x = 0, 0.05, 0.1, 0.15, 0.2, 0.25, and 0.3 using the auto combustion method (sol-gel). The citric acid was used as fuel for auto combustion. The X-ray diffraction (XRD) test showed an increase in the crystal lattice constant, which is of face-centered cubic (FCC) structure. Field Emission Scanning Electron Microscopy (FE-SEM) showed that the compound has apparent porosity; its grains are spherical or semi-spherical and within the nanoscale. The Energy-Dispersive X-ray spectroscopy (EDX) proved the presence of all the elements involved in the preparation of the compound, and there are no other elements, which means that it is of high purity. The vibrating sample magnetometer (VSM) showed that the hysteresis loop is small and narrow, meaning the wasted energy is as little as possible. In addition, it was found that the compound has good sensitivity to NO2 gas.

Amplification of intense red emission through integrating Li+ ions to V2O5:Eu3+ phosphors: Optical thermometry, cheiloscopy and extraction of level III features for individual identification

This study presents the synthesis of V2O5:Eu3+ phosphors in concentrations ranging from 1 to 9 mol %, using a solution combustion method with Areca Nut (A.N) as a bio-fuel. The samples exhibit an orthorhombic crystal structure, confirmed by powder X-ray diffraction (PXRD), and rod-like morphology as shown by field emission scanning electron microscopy (FE-SEM). Photoluminescence (PL) studies reveal that the emission intensity of the 5D0→7F2 transition at 619 nm increases with the Eu3+ concentration up to 5 mol %, where it peaks before quenching due to quadruple-quadruple interactions, according to the Van Uitert relation. To improve luminescence, Li+ ions are added, with the V2O5:5Eu3+ co-doped with 4Li+ (V2O5:5Eu3+, 4Li+) ions showing the highest PL intensity, about 5.03 times higher than that of Eu3+ alone. This optimized phosphor has Commission Internationale de l’Eclairage (CIE) chromaticity coordinates of (0.6022, 0.3963), closely matching commercial red-emitting phosphors and demonstrating a colour purity (CP) of 88.69 %. Thermal stability assessments indicate that these phosphors have a high activation energy (Ea) of about 0.224 eV, signifying robust thermal properties. The optimized V2O5:5Eu3+, 4Li+ phosphors efficiently reveal level I–III features in latent fingerprints (LFPs) and accurately identify lip prints (LPs) groove patterns of type I–VI under 365 nm UV light, providing high resolution and contrast. These characteristics make the optimized phosphor an excellent candidate for use in photonic devices, advanced forensic and data security applications.

Green auto-combustion synthesis of SrNiO3/NiO/SrCO3 ferromagnetic-nanocomposites in the presence carbohydrate sugars and their application as photocatalyst for degradation of water-soluble organic-pollutants

This study utilized an environmentally-friendly method to synthesize SrNiO3/NiO/SrCO3 nanocomposites using glucose and lactose as fuels. A variety of fuel concentrations were investigated in order to determine their effects on SrNiO3/NiO/SrCO3 nanocomposites from both a pure and a morphological perspective. Various physiochemical techniques were employed to examine the crystal structure, morphology, optical, magnetic, and surface properties of the synthesized nanoparticles. These techniques included X-ray diffract, scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy (EDS), Fourier-Transform Infrared Spectroscopy (FTIR), vibrating sample magnetometers, and Brunauer-Emmett-Tellers. The band gap of the as-synthesized nanoparticles was determined to be 2.5eV, suggesting that they are capable of acting as a photocatalyst under sunlight-like conditions. The photocatalytic activity of SrNiO3/NiO/SrCO3 nanocomposites was evaluated against Methyl orange (MO) and Methyl violet (MV), and the mechanism of the photocatalyst was investigated using EDTA, benzoic acid, and benzoquinone as scavengers. A comparison of photocatalytic activity in UV and sun-like light showed that maximum degradation (92%) and (84.8%) were related to degradation of MO (20 ppm) and MV in 60min, respectively. The results indicate that SrNiO3/NiO/SrCO3 nanocomposites synthesized using the auto combustion method may serve as a promising photocatalyst for the degradation of organic pollutants in the environment within a short period of time.

Photocatalytic and eco-emission applications of green synthesized ZnO-CB nanoparticles

Herein, we report the synthesis of ZnO nanoparticles (ZnO-CB NPs) by employing the solution combustion method using an aqueous extract of brinjal calyxes as fuel. Characterization techniques, such as X-ray diffraction (XRD), Fourier transform Infrared spectroscopy (FTIR), UV–visible spectroscopy, and Scanning electron microscopy (SEM), were used to investigate the structural, optical, and morphological properties of synthesized nanoparticles, respectively. Highly porous hexagonal crystalline ZnO-CB NPs with less than 7 nm particle size were obtained. The photocatalytic performance of synthesized material is measured with Malachite green (MG), Basic brown 1 (BB1), and Acid orange 36 (AO36) as benchmark dyes. It showed that the synthesized material worked effectively under pH 10 with UV light irradiation. The synthesized ZnO-CB NP shows good removal effectiveness of the MG, BB1, and AO36 dyes with 99.3 %, 99.6 %, and 99.5 %, respectively, which can be promising photocatalysts for ecological applications such as wastewater remediation. Further, the synthesized ZnO-CB NP was used as blends in the methyl ester of Millettia pinnata oil (MPME), which is blended 20 % with commercial diesel (MPME20). The synthesized ZnO-CB NP was added to the MPME20 in varying amounts to ascertain its effects on the quality of emissions of various greenhouse gases such as hydrocarbons, COx, and NOx. Moreover, brake thermal efficiency (BTHE) and brake-specific fuel consumption (BSFC) were studied for the blends. The blend MPME20 with 25 mg of ZnO-CB NP, i.e., MPME20-25 mg, ZnO-CB, displays the best performance and reduced emissions.

[formula omitted] leaves mediated combustion synthesis of Tb[formula omitted] doped Zn2V2O7 nanoparticles: Color tunable photoluminescence and electrochemical studies for display and supercapacitor applications

A new series of Tb3+ doped Zn2V2O7 (ZV) nanoparticles (NPs) at different concentration from 1 to 9 mol% was synthesized by Menthaspicata leaves extract mediated solution combustion method. On Tb3+ doping, the diffraction pattern matches well with the monoclinic crystal structure with the C2/c(2/m) space group of ZV host matrix. The surface morphology tuned from irregular shaped NPs to hexagonal shaped NPs with variation in dopant concentration. The crystallite size estimated from Scherrer’s method matches well with the transmission electron microscopy analysis. The optical band gap determined from Tauc’s plot utilizing UV–Visible absorption was tuned from 3.061 to 3.035 eV with increase in dopant concentration. Under 266 nm excitation, the emission of Tb3+ ions from Tb3+-doped ZV NPs is observed, with the intensity of emission showing sensitivity to the concentration of Tb3+ ions. The optimal doping content is determined to be 7 mol %. The CIE coordinates clearly indicates the tuning of the emission color from green to blue region with increase in dopant concentration. The average color coordinated temperature was found to be 7895 K showing the cooler appearance. Further, cyclic voltammetry analysis offers valuable insights into redox reactions, electrode kinetics, and overall electrochemical behavior, while Electrochemical Impedance Spectroscopy (EIS) provides information on ion transport kinetics. Galvanostatic Charge–Discharge (GCD) analysis revealed supercapacitance values ranging from 79.43 to 133.26 F/g at 10 mV/s with increasing dopant concentration. These findings underscore the potential of this material for use in energy storage and display technology applications.

Synthesis of Zn0.87(Fe, Al)0.065O – MO (MO = NiO, Fe2O3, CuO, and CoO) nanocomposites: Structural, vibrational, optical and antibacterial studies

One of the most effective strategies for achieving high-performance antibacterial activity is the synthesis of nanocomposites by combining different nanoparticles. Hence, Zn0.87(Fe, Al)0.065O – MO (NiO, Fe2O3, CuO and CoO) nanocomposites (NCs) with a 7:3 molar ratio were synthesized via the solution combustion method. The produced NCs structural, vibrational, and optical characteristics were investigated using XRD, FTIR, UV–Vis, and PL spectroscopies. The standard disc diffusion method was used to evaluate the antibacterial efficacy of the NCs. The lattice constant, crystallite size, bond length, dislocation density, and other relevant parameters of the NCs were also evaluated. XRD analysis revealed a well-defined mixed-phase structure for all 0.7Zn0.87(Fe, Al)0.065O – 0.3NiO (ZFA-Ni), 0.7Zn0.87(Fe, Al)0.065O – 0.3Fe2O3 (ZFA-Fe), 0.7Zn0.87(Fe, Al)0.065O – 0.3CuO (ZFA-Cu) and 0.7Zn0.87(Fe, Al)0.065O – 0.3CoO (ZFA-Co) NCs, indicating successful mixing of each metal oxide with the ZnO matrix. The average crystallite size within the NCs ranged from 14.21 to 18.10 nm, suggesting a degree of nanocrystallinity nature of all NCs. FTIR confirmed the presence of characteristic functional groups within the NCs. Moreover, all the synthesized NCs exhibited significant optical activation in the ultraviolet radiation range but visible light absorption was also observed when the composite formed with CuO and Fe2O3 nanoparticles. The band gap energy values exhibited variation between 2.72 eV for ZFA-Co NC and 2.90 eV for ZFA-Ni NC. Photoluminescence (PL) emission in the composite formation of ZnO NPs with other metal oxide were significantly influenced by the absorption range of the composite with pn-junction formation in a notable enhancement of antibacterial efficacy against bacterial strains of Escherichia coli and Staphylococcus aureus. Particularly, ZFA-Co NC exhibited an excellent antibacterial performance against both bacterial strains.

Effect of calcination temperature on structural, optical, and morphological properties of RAlO3 (R = La, Sm) perovskite oxides

RAlO3 (R = La, Sm) have attracted the research community due to their interesting optoelectronic properties and viable applications. The solution combustion method allows for a faster process and lower calcination temperature than the traditional solid-state method and is an economical alternative to wet chemical synthesis for producing RAlO3. This work explores the thermal, structural, morphological, optical, and electrical properties of RAlO3 (R = La, Sm) synthesised by the solution combustion method using urea as fuel. Thermogravimetric analysis—differential thermal analysis (TGA-DTA) showed the crystallization temperatures of lanthanum aluminate (LaAlO3) and samarium aluminate (SmAlO3) at 864 and 887 °C, respectively. The x-ray diffraction (XRD) and Rietveld analysis revealed the structure of LaAlO3 as rhombohedral (R-3c) and SmAlO3 as orthorhombic (Pbnm). The LaAlO3 and SmAlO3 samples calcinated at 800 °C showed crystallite size (D) of 19.26 nm and 19.06 nm, respectively. The field emission scanning electron microscopy (FE-SEM) images show a highly porous and large sheet-like morphology with voids and cracks. High resolution transmission electron microscopy (HR-TEM) images and the selective area electron diffraction (SAED) pattern show crystalline nature and the indexed planes agreed with the XRD results. The LaAlO3 and SmAlO3 samples had specific surface areas of 16.374 and 12.953 m2 g−1, respectively. The TGA-DTA results were affirmed by Fourier transform infrared spectroscopy (FT-IR) results which showed only the presence of metal-oxide bonds for materials annealed at and above 800 °C. These results were further validated by the electron dispersive x-ray spectroscopy (EDX) and the x-ray photoelectron spectroscopy (XPS) showing no additional peaks. The band gap of 5.08 and 4.82 eV were calculated from ultraviolet-visible spectroscopy (UV–vis) for LaAlO3 and SmAlO3, respectively. The results imply that the solution combustion technique using urea as fuel is a viable route for synthesising RAlO3.

Facile green synthesis of Bi2S3 nanoparticles: Applications in simultaneous dye degradation and seed germination of fenugreek seeds

In this work, Bi2S3 nanoparticles (NPs) have been synthesized by the green combustion method at 500 °C for 10 min using C.argentae. The structure, optical, and morphological studies of the synthesized material were analysed using PXRD, FTIR, UV, PL, and SEM spectroscopy techniques. The PXRD pattern of the material demonstrates that the obtained particles are of bismuth sulphide with an orthorhombic structure. The FTIR spectrum of it shows a characteristic peak at 606.8 cm−1. In the UV–visible spectrum, on extrapolating the linear portion of the curve, the band gap on the X-axis is found to be 3.17 eV. PL intensity peaks show excitation and emission ranges of 384 nm and 532 nm respectively. SEM studies of the material show that the nanoparticles are in granular shape. Further, by using synthesized nanomaterials, photocatalytic degradation is carried out for methylene blue dye with different variations, and scavenger activity is carried out using K2Cr2O7, EDTA, ascorbic acid, and TBA. Seed germination activity is also carried out for fenugreek seeds with synthesized material and dye, with dye, and with a mixture of dye and nanoparticles, along with the simultaneous study of dye degradation.