Solution Combustion Approach Research Articles

Effect of pH on the microstructure and antibacterial properties of MgO nanoparticles by microwave-assisted solution combustion

The application of magnesium oxide (MgO) nanoparticles as a candidate material for antibacterial purposes has been limited by their relatively low antibacterial activity. In this study, antibacterial MgO nanoparticles were synthesised in one step using magnesium nitrate and citric acid as raw materials using an economical and environmentally friendly microwave-assisted solution combustion approach, while the effect of the pH of the reaction system (2, 4, and 7) on the structure and antimicrobial properties of the synthesised MgO nanoparticles was investigated. X-ray diffraction (XRD) analysis demonstrated the formation of cubic-phase MgO nanoparticles, and electron microscopy studies confirmed that MgO nanoparticles synthesised at a precursor solution pH of 4 had uniform size distribution with a small microcrystalline size (∼19 nm) and spherical granular morphology. In addition, the results of the plate colony counting method showed that the antibacterial rate of MgO-4 against Gram-negative Escherichia coli (106 CFU/mL) at a sample concentration of 100 μg/mL was as high as 99.86 %, which showed excellent antibacterial performance. These findings provide valuable insights into how to increase the degree of oxygen adsorption on the sample surface to participate in the reaction, as well as a potential method for constructing nanomaterials with high antimicrobial activity.

Thermoluminescence (TL) properties of Eu3+ incorporated with CaB4O7 phosphors prepared by solution-combustion process

The solution-combustion approach was used to create CaB4O7:Eu3+phosphors using Ba (NO3)2, Eu (NO3)3·5H2O, H3BO3, NH3(ON)H2, and NH4NO3 as source materials. We investigated the thermoluminescence (TL) characteristics of beta (β)-irradiated CaB4O7:Eu3+. When the TL intensity was evaluated at different dosages of β, it rose with the dose. Changes in peak temperature were observed because of the investigation of the effects of varying heating rates on TL glow curves. Moreover, the positions of the peak temperature and the TL intensity did not change when the same sample was measured again, suggesting that the sample was stable. Additionally, the study calculated several kinetic parameters, including activation energy (E), frequency factor (s), and geometrical factor (μg), for distinct TL glow curves. Through geometric analysis of TL glow peaks, the study determined activation energies and kinetic orders, enabling the calculation of the frequency factor. The findings highlight the suitability of the prepared phosphor for dosimetry and provide insights into trap characteristics crucial for continuous illumination at room temperature. The study also emphasises the importance of optimising trap depth for prolonged afterglow, shedding light on the interplay between trap energies and luminescence characteristics. These findings deepen our comprehension of phosphor behavior and open the door to better dosimetry applications.

Structural and LuminescentProperties of Dy(III) DopedCa0.5Bi3P2O10 Nanophosphors for Solid-State Lighting& Latent Fingerprinting Applications.

Anefficient urea-assisted SC (solution-combustion)approach was used to synthesize a novel series ofdoped Ca0.5Bi3P2O10: xDy3+ nanophosphors (0.01-0.1mol). The powdered materials were thoroughly investigated using structural and optical measures. 'Rietveld refinement'investigations found that the produced nanophosphorformed a triclinic system with the P -1 triclinic space group. An EDS (energy-dispersive spectral)study was conducted to determine the corresponding proportions of constituentelements of doped nanophosphors. The TEM (transmission electron microscopy)revealed aggregated particles with a standard size onthe nanoscale. The PLE (Photoluminescence excitation)spectrum indicates that the indicated phosphors can be stimulated by NUV (near ultraviolet)illumination sources. The Dy3+-ions undergo transitions from (4F9/2 → 6H15/2 & 4F9/2 → 6H13/2) were recognized as (PL) spectra with an excitation of 353nm revealed the presence of blue-yellow bands at 481, and 577nm, correspondingly. Further, PL data was used to determine photometric metrics such as CCT (correlated color-temperature), CC (chromaticity-coordinates (x &y)), and CP (color-purity (%)), supporting their use in solid-state lighting and latent fingerprinting applications.

Investigations of adsorption and photoluminescence properties of encapsulated Al–ZnO nanostructures: Synthesis, morphology and dye degradation studies

This study focuses on the solution combustion approach to examine the nanostructures of undoped and doped ZnO with different concentrations of Al (0.1 % and 0.2 %). Various physical techniques were utilized to characterize the synthesized nanoparticles. X-ray diffraction (XRD) revealed the crystalline materials, while scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) findings confirmed the products with particle size and the insertion of Al into the ZnO lattice. Fourier-transform infrared spectra (FTIR) confirmed the presence of different functional groups in the obtained material. The results indicate that Al-doped ZnO (Al–ZnO) nanoparticles show promising properties for optoelectronics and photoluminescence. Photoluminescence analysis indicated that an increase in Al3+ (0.2 %) concentration resulted in a decrease in peak intensity and an increase in the full width at half maximum. The band gap was calculated using the Taucs plot. The study also highlights the effectiveness of Zn1-xAlxO nanostructures in degrading organic pollutants, particularly in adsorbing Malachite Green (MG) dye. Among the samples, the 0.2 % Al-doped ZnO exhibited superior dye degradation efficiency due to its enhanced adsorption capacity and smaller particle size, as evidenced by multilayer adsorption capacity and chemisorption during the degradation process. This study provides valuable insights into the potential applications of Al-doped ZnO nanoparticles in various environmental and technological fields, emphasizing their significance in the degradation of organic pollutants.

Solution combustion synthesis and exploration of chromium reduction and organic dyes degradation of cobalt tungstate (CoWO4) nanoparticles

Facile preparation route for cobalt tungstate (CoWO4) via cost effective, time saving, easy and solution combustion approach is described in the present paper. The structural, morphological properties of cobalt tungstate characterized by different physiochemical techniques which include X-ray diffraction, scanning electron microscopy (SEM), energy dispersive X-ray absorption (EDS). The optical properties assessed by UV–visible spectroscopy (DRS) and photoluminescence spectroscopy (PL). Using these methods, it was discovered that CoWO4 which has been synthesized displayed a monoclinic phase of Wolframite with great crystallinity and purity. The average crystallite size of prepared CoWO4 was 22 nm and band gap obtained was 2.84 eV due to which it can be used as visible light photocatalyst in aqueous medium. As a result, in this study, the photocatalytic degradation ability of CoWO4 was assessed by observing the aqueous phase degradation of the most widely used dyes, methylene blue (MB) and Rhodamine-B as well as Cr(VI) reduction under visible light. Almost all MB degraded in 90 min whereas 69 % degradation of RhB takes place in 240 min under visible light irradation. The different aspects for low rate of photodegradation of RhB dye than MB dye was also discussed in this report. The present study deals advanced approach that CoWO4 can also be used as capable visible light photocatalyst for degradation of dangerous contaminants and for reduction of carcinogenic Cr(VI) into nontoxic Cr(III) from waste water.

Green Synthesis of NiO Nanoparticles using Pongamia pinnata and their Catalytic Utility in the Snthesis of N-Fmoc/Cbz-protected Amino Acid Derived Sulfides and their Biological Investigations

Introduction:: Synthesis of NiO nanoparticles using environmentally friendly Pongamia pinnata seeds as a source of fuel was demonstrated using a solution combustion approach. Method:: The protocol for the synthesis of NiO NPs is simple and efficient. NiO NPs were utilized as the catalyst for the synthesis of N-protected aminoalkyl sulfides from N-protected alkyl thiols and bromo esters of amino acids. Results:: The NiO NPs were characterized using XRD, SEM, and EDX techniques. N-protected aminoalkyl sulfides were characterized by HRMS, 1H, and 13C NMR techniques and were evaluated for their in vitro antifungal activities, against A. Niger using Fluconazole as a standard. Conclusion:: The current study presents an effective approach for synthesizing a new class of sulfides from N-protected aminoalkyl thiols and bromomethyl esters in the presence of nano NiO as a catalyst.

Three-Dimensional Mesoporous Ni-CeO2 Catalyst for Dry Reforming of Methane

Using the colloidal solution combustion approach, a three-dimensional mesoporous 5%Ni-CeO2-M catalyst was developed, with Ni incorporated into the pores, and applied in the dry reforming of methane. Comprehensive characterization revealed that the 5%Ni-CeO2-M catalyst had a large specific surface area and a three-dimensional mesoporous structure. A rich Ni-CeO2 interface was formed by closely spaced tiny CeO2 and NiO nanoparticles within the spherical pore wall. With very little carbon deposition over a 100 h period at 700 °C, the catalyst showed excellent activity and stability. The tiny Ni nanoparticles, along with the substantial Ni-CeO2 interfaces that make up this three-dimensional in-form mesoporous catalyst, are responsible for the outstanding effectiveness of this 5%Ni-CeO2-M catalyst.

Synthesis, characterization and application of rare earth (Lu3+) doped zinc ferrites in carbon monoxide gas sensing and supercapacitors

The novel rare earth (Lu) doped zinc ferrite nanoparticles, synthesized via a solution combustion approach, exhibit exceptional sensitivity to carbon monoxide (C.O.), a capability studied for the first time. The successful detection of C.O. by these nanoparticles underscores their potential as efficient gas sensors. Structural and morphological characterization confirmed the creation of single-phase zinc ferrite nanoparticles, utilizing various standard and advanced modern probes.To assess the gas sensing capabilities, the nanoparticles were exposed to carbon monoxide gas, revealing an outstanding gas response of 80 % at 300 °C, with a response against 20,000 parts per million by volume (PPMv) of carbon monoxide. These results indicate the promising applicability of Lu-doped zinc ferrite nanoparticles in C.O. gas sensing applications.Furthermore, the supercapacitance performance of the synthesized nanoparticles was investigated. Electrodes fabricated from Lu-doped zinc ferrite nanoparticles (Lu 0, 0.3, 0.5, and 0.7) were examined in a 3 M K.O.H. electrolyte using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (E.I.S.). The electrochemical properties of all nanoparticles exhibited good Faradaic behaviour, with the Lu 0.7 electrode achieving a high specific capacitance of 280 F/g at a current density of 0.25 A/g. This highlights the prominent electrochemical stability and potential applications of Lu-doped zinc ferrite nanoparticles in energy storage devices.Overall, the comprehensive investigation of the gas sensing and super capacitance performance of Lu-doped zinc ferrite nanoparticles demonstrates their versatility and potential for various technological applications, including gas sensing and energy storage. These findings pave the way for further research and development in utilizing rare earth-doped ferrite nanoparticles for advanced functional materials.

Combustion synthesis, structural and photoluminescent investigations of Eu3+ activated crystalline Ba2BiV3O11 nanomaterials for multifunctional applications

Nanocrystalline Ba2BiV3O11 phosphor activated with lanthanide ion (Eu3+) has been successfully developed via a solution combustion approach. Various characterization techniques were implemented to explore the crystal structure, morphological behavior, photoluminescence, and chromatic aspects of Eu3+: Ba2BiV3O11 nanophosphors. Rietveld refinement was exercised to attain the phase purity and various crystallographic parameters. Transmission Electron Microscopy (TEM) technique was employed to analyze the crystallite size of the developed nanocrystals which is also in agreement with the size calculated from Scherrer formalization and W-H (Williamson-Hall) plot. Morphological behavior was studied with the help of Scanning Electron Microscopy (SEM) measurements. The most intense peak centered at 622 nm (5D0 → 7F2) in emission spectra was noted for Eu3+: Ba2BiV3O11 nanophosphors under 348 nm excitation. Kubelka-Munk function computed the Egap for the host along with the optimized sample and the outcomes evolved as 3.47 eV and 3.41 eV, respectively. Auzel’s model was executed to attain the radiative lifetime (1.3467 ms) for 5D0 electronic state. The CIE coordinates (x = 0.5990, y = 0.4003), CCT values (1710 K), quantum efficiency (87 %), and emission of bright red light indicate the promising behavior of Ba2Bi0.9Eu0.1V3O11 nanophosphor to use in the imaging applications, wLEDs, temperature sensing, and solid-state lighting (SSLs) appliances.

Ag-Fe2O3 nanocomposites for synergistically enhanced antibacterial activity

Doping of metal or metal ions in the host lattice with good dopant distribution or forming a local contact boosts materials properties for specific applications. This work used the solution combustion approach (SCA) to synthesize Ag-Fe2O3 nanocomposites (SICs) following the single-source precursor doping strategy with good final material stoichiometry. The elemental distribution and composition, crystallinity, and morphology of SCA-based synthesized materials were analyzed using common techniques such as TEM, FESEM-EDS, and XRD. Even though the Lewis hard and soft acids and bases (HSAB) idea was precise for inclusion of Ag dopant in the Fe2O3 lattice, the formation of Schottky junctions between Ag and Fe2O3 is dominance as a result of dopant-host radii size differences. The independent peak for both Ag and Fe2O3 crystals on the XRD pattern analysis without peak shift confirms the dominance of Schottky junction formation. The presence of local contact between Ag and Fe2O3 was also confirmed by the HRTEM analysis, with d-spacing values of 0.22 and 0.36 nm, respectively. Compared to the bare Fe2O3, the antibacterial potential of the SIC is much greater, with a 23-mm zone of inhibition on Pseudomonas aeruginosa gram-negative bacteria, which confirms the presence of a synergistic effect.

Facile solution combustion synthesis of mesoporous HfTiO4 as novel photoanode material with enhanced visible-light response

In this research endeavor, we report the successful synthesis of mesoporous and single-phase nanopowders of orthorhombic hafnium titanate, HfTiO4, using a facile solution combustion approach. The direct synthesis yielded an X-ray amorphous product, which was found to crystallize completely into single-phase HfTiO4 upon annealing at 800 °C for 1 h, marking the first successful synthesis of this material via this method. The synthesized HfTiO4 nanopowders were thoroughly characterized using various techniques. Structural analyses conducted through powder X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy confirmed the formation of pure orthorhombic HfTiO4 nanocrystals, exhibiting an average size of 24.6 nm. Moreover, the scanning electron microscopy (SEM) morphological study and adsorption-structural analysis of the HfTiO4 nanopowder revealed a well-developed mesoporous structure with a specific surface area of 17 m2/g and an average pore size of 15 nm. The band gap of the synthesized HfTiO4 was determined to be 3.47 eV, designating it as a potential photoanode material. Photocatalytic applications were evaluated through photoelectrochemical tests, which showcased a high photoresponse in both the UV (365 nm) and visible (450 nm) regions of the spectrum. Importantly, the photoresponse under visible light surpassed that of commercial TiO2 (Sigma-Aldrich), signifying its potential as an efficient photoanode material.

Marigold flower like Co3O4 nanoparticles as high performance electrodes for supercapacitors

Transition metal oxides promised as electrode materials for supercapacitors have received much interest, especially cobalt oxide (Co3O4) nanoparticles. However, the low intrinsic electrical conductivity and aggregation of Co3O4 nanoparticles limit their electrochemical performance and impede the commercialization of these electrode materials. The present study describes a simple, and cost-effective solution combustion approach for producing marigold Co3O4 at 300 °C. Further, the effect of vacuum annealing on the microstructural and electrochemical properties is studied to explore the nanostructured samples of Co3O4 as potential electrode material. The electrochemical nature of prepared marigold Co3O4 nanoparticles in 3 M KOH aqueous electrolyte has the highest specific capacitance of 603 Fg−1 at a scan rate of 1 mVs−1 with greater electrochemical stability even after 5000 cycles. The possible reasons for a decrease in specific capacitance on annealing of as prepared Co3O4 at 300 °C are explored in this paper and some significant reasons are highlighted.

Antibacterial and photocatalytic properties of Ag-doped CeO2:BaO synthesized by simple solution combustion method

Ag-doped CeO2:BaO (ACBO) composite was synthesized by the simple solution combustion approach and investigated for its antibacterial and photocatalytic properties. CeO2 was doped with Ag 0.0–2.0 wt% as a part of the ACBO composite. Best antibacterial activity (ZOI = 13 mm) was measured against Bacillus by ACBO with 2.0 wt% Ag among the Pseudomonas, Bacillus, Staphylococcus and E. coli in comparison to Ciprofloxacin. Photocatalytic action against the methyl blue (598 nm) was also inspected, and a maximum degradation efficacy of 76% for the 2.0 wt% ACBO was observed in 16 min.

Aloe vera-mediated green synthesis of bismuth-zinc-iron nanocomposite for radiation shielding applications

In this study, bismuth zinc iron (BiZnFe) nanocomposites (NCs) were synthesized for the first time using a solution combustion approach and Aloe vera extract as a reducing agent. The morphology was determined for the NCs using scanning electron microscopy. X-ray diffraction and Fourier transform-infrared spectroscopy were applied to analyze the physical and chemical structures of the new NCs, and synthesis of the NCs was validated. Ultraviolet light absorption was observed in the wavelength region of 200–300 nm,and the direct energy bandgap was determined as 3.06eV.The capacity of the BiZnFe NCs to shield against various types of radiation was assessed, i.e. X-rays/gamma rays, bremsstrahlung, and neutrons.In the lower energy range, the gamma shielding efficiency was equivalent to lead but lower than that of lead in the higher energy range. The bremsstrahlung exposure constant for BiZnFe NCs was comparable to those for concrete and steel, but less than that for lead. Compared with lead, the BiZnFe NCs exhibited strong radiation absorption and minimal secondary radiation emission, which are their main strengths. Furthermore, the BiZnFe NCs have been demonstrated to have much greater neutron shielding capabilities than lead, steel, and concrete in terms of scattering length, absorption, and scattering cross-sections.

Synergistically Augmented ZnO via Cobalt and Copper Simultaneous Doping for Pollutant Reduction

AbstractContinuous electron‐hole transfer and the ability of nanoscale materials to absorb visible light are critical for pollutant catalytic reduction. Cobalt and copper co‐doped ZnO composites were shaped by the sol‐gel solution combustion (SG‐SC) approach. The x‐ray diffraction analysis confirmed the crystalline nature and interstitial doping of copper and cobalt in the zinc oxide lattice and the development of ZnO‐CuO local contact. The PL and DRS‐UV‐vis investigations showed the NCs’ superior charge transfer and considerable redshift (from 3.17 to 2.21 eV) properties over ZnO. TEM and SEM‐EDS analyses confirmed the foam‐type surface morphology, elemental composition, and dopant distribution. The NCs showed greater potency than ZnO NPs in the catalytic reduction reactions of 4‐nitrophenol and methylene blue. Thus, the SG‐SC approach has the potential for industrially scalable catalytic pollutant reduction applications.

Synthesis, structural and morphological characterization of α-Bi2O3 nanostructure for photocatalytic hydrogen production and degradation of organic pollutants

This study used a solution combustion approach to develop α-Bi2O3 nanostructure with tunable structural phase and surface morphology for photocatalytic hydrogen production and methylene blue (MB) photodegradation under artificial visible light (50 W LED light). Powder X-ray diffractometer (PXRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), UV–Visible diffuse reflectance spectroscopy (DRS UV–Vis), and Fourier transform infrared (FTIR) spectroscopy were used to investigate the structural, morphological, and optical properties of the prepared α-Bi2O3 photocatalysts. XRD patterns and FTIR analysis showed excellent crystalline structure and high purity of the prepared samples. SEM images demonstrated the morphological transformation of α-Bi2O3 from nanoball to nanosheet with increasing the fuel and oxidizer ratios. DRS UV–Vis analysis revealed excellent optical properties of the prepared α-Bi2O3 nanostructures. Under 50 W LED light irradiation, the as-prepared α-Bi2O3 demonstrated 92% photodegradation of MB in 30 min and 45 μmol of photocatalytic hydrogen production in one hour. The result indicates a morphological-dependent photocatalytic efficiency. This study paves the way for developing photocatalytic semiconductors with various morphologies via a solution combustion route for efficient photocatalysts.

Synthesis of copper-silver-zinc oxide nanocomposites for 4-nitrophenol reduction: doping and heterojunction.

The charge transfer and visible-light absorption capacities of stable materials are crucial in several applications, such as catalysis, absorption, sensors, and bioremediation. Copper-silver-zinc oxide nanocomposites (NCs) were synthesized using PVA as a capping agent and urea as a stabilizing agent. DTG analysis confirmed 500 °C was the optimum temperature for the total decomposition of PVA after capping the nanoparticles (NPs) to yield a pure composite. The XRD analysis showed the presence of copper inclusions in the ZnO lattice and the formation of Ag and CuO heterojunctions with ZnO. The photoluminescence (PL) analysis confirmed the more significant visible light absorption and charge transfer properties of the composite compared to those of single ZnO NPs. Foam-type porosity occurred during gas evolution at many of the points shown in the SEM/TEM images. Slight lattice fringe differences between the composite and ZnO NPs due to copper inclusion were confirmed from the HRTEM image and XRD pattern analysis. The crystallinity of the NPs and NCs was confirmed by the XRD pattern and SAED analysis. The diffusion-controlled charge transfer process was witnessed through CV electrochemical analysis. Thus, the energy- and time-efficient solution combustion synthesis (SCS) approach has a crucial future outlook, specifically for an industrial, scalable application. The NCs demonstrated more potential than ZnO NPs in an organic catalytic reduction reaction of 4-nitrophenol to 4-aminophenol.

Synthesis of highly active and visible-light-driven PrFeO3 photocatalyst using solution combustion approach and succinic acid as fuel

Synthesis of highly active and visible-light-driven PrFeO3 photocatalyst using solution combustion approach and succinic acid as fuel

Evaluation of Structural and Functional Properties of La0.6Sr0.4MnO3 Perovskite Prepared by the Fast Solution Combustion Approach

A series of La0.6Sr0.4MnO3 (LSM) perovskite was made using the rapid solution combustion method, which was calcined by varying the temperatures. In order to determine how the calcination temperature affected the nanopowders produced and calcined at various temperatures, their microstructural, morphological, compositional, optical, and electrical properties were analyzed using corresponding characterization tools. The XRD results showed the coexistence of the rhombohedral polymorphs R-3c and Pm-3m for the perovskite phase under a calcination temperature of 1400 °C, which were eliminated with increased calcination temperature. The average grain size was found to increase with increasing calcination temperature. The EDS analysis showed better agreement of the stoichiometry with the theoretical composition. The apparent porosity decreased with increasing temperature due to the coalescence of sintering pores. The sample obtained after calcination at 1500 °C showed 10.3% porosity. The hardness also improved with increasing calcination temperature and reached a maximum value of 0.4 GPa, which matched the bulk density. A similar trend was observed in the resistivity studies as a function of temperature, and all the samples exhibited a low resistivity of ~1.4 Ω·cm in the temperature range of 500–600 °C. The optical characterization showed broad absorption at 560–660 nm and bandwidth values between 3.70 and 3.95 eV, according to the applied heat treatment.

Opto-electronic, crystallographic, and Judd-Ofelt analysis of novel gadolinium-based europium doped BaSrGd4O8 nanophosphor for advanced pc-WLEDs

• Red-light emanating BaSrGd 4 O 8 :Eu 3+ nanocrystals have been prepared for first time via urea assisted solution combustion approach. • The detailed structural and photoluminescence analysis are done effectively. • SEM, TEM, EDAX, and TGA characterizations are done to explore morphological aspects, elemental analysis and thermal stability. • Kubelka-Munk hypothesis has been utilized to determine band-gap energy using DR spectra. • Significant utilization in various photonic and solid-state lighting applications. A sequence of novel BaSrGd 4 O 8 :Eu 3+ nanophosphor was fabricated with the aid of solution combustion (SC) methodology. Phase formed and morphological attributes were examined by PXRD, SEM, and TEM techniques. Rietveld refinement confirmed the Space group Pnma (62) and Orthorhombic phase. Diffuse reflectance, decay curves, and photoluminescence spectra were utilized to look into the photoluminescent features. Exclusive red emission was observed due to the 5 D 0 → 7 F 2 transition with optimal composition found at 15.0 mol %. The decay lifetime and quantum efficiency for the optimized nanophosphor were found to be 1.5495 ms and 72.5 %. Energy band gap values for the host matrix as well as optimized sample were also calculated that were found to be 5.27 and 3.46 eV respectively. CIE and CCT coordinates confirmed an efficient red emission that enhances its application vision in optical appliances.