Simple Combustion Research Articles

Study on Effect of Cations Addition to Mg-Zn Ferrite Nanoparticles: Synthesis and Characterisation

The spinel ferrite nanoparticles have gained huge interest in several technological applications. Synthesis methods and the components of ferrites paly vital role in their features and the present work focus on the same. Various cations such as Bi, Ba, Ag and Cu substituted magnesium ferrites were synthesised using simple solution combustion method. The ferrites were characterised using XRD, FESEM and FTIR for their structure as well as morphology. The morpholocial changes were significant with the variation of cations such as Ba, Ag, Bi and Ca. The one with bismuth interestingly showed flake like morphology and other have showed the mixed morphology. Ferrites with Bi and Ba exhibited greater size than the ones with Ag and Ca. The study aims for the comparison on the varied features of ferrites upon cation variation.

Acetylacetone as a new fuel for simple combustion sol-gel processing of NiCo2O4 nano-porous thin films

Nickel-cobaltite films (NiCo2O4) are promising electrodes for a variety of applications, including solar cells and supercapacitors. Therefore, numerous studies have investigated synthesis methods to tailor the properties of this compound for specific applications. In this article, we investigate acetylacetone as a fuel in the combustion process to synthesize NiCo2O4 (NCO) films. By X-ray diffraction and Raman spectroscopy, we confirmed the crystallinity and purity of the spinel phase for the deposited films. Furthermore, we investigated the morphology of the films by field emission scanning electron microscopy and found a tendency towards a nanoporous microstructure at higher annealing temperatures. The deposited films exhibit good optical transmission in the near-infrared and visible spectrum. In addition, the band gap decreased slightly from 2.33eV to 2.2eV with increasing annealing temperature. The electrical properties were investigated using the hot-probe and four-probe methods. The measurements revealed a p-type semiconductor behavior and a maximum electrical conductivity of 25.8 S.cm-1 for the films annealed at 450°C.

Combustion synthesis of TiO2/C composites for enhanced photocatalytic H2O2 production and solar steam evaporation efficiency

In this work, a simple combustion method was proposed for the controllable synthesis of TiO2/C composites, which can achieve both the efficient solar water evaporation at the interface and photocatalytic H2O2 production. Structural and morphological characteristic indicated the co-existence of carbon quantum dots and amorphous carbon, which were well distributed on the surface of the TiO2. TiO2/C composites displayed the enhanced visible light absorption and the rapid separation of photogenerated electron-hole pairs. TiO2/C-10 exhibited an excellent photocatalytic H2O2 production activity of 3068.46 μmol/g/h under the simulated solar irradiation. Besides, its water evaporation rate reached up to 5.81 kg·m−2·h−1 under the simulated solar irradiation.

An Active and Regenerable Nanometric High‐Entropy Catalyst for Efficient Propane Dehydrogenation

AbstractPropane dehydrogenation (PDH) is crucial for propylene production, but commercially employed Pt‐based catalysts face susceptibility to deactivation due to the Pt sintering during reaction and regeneration steps. Here, we report a SiO2 supported nanometric (MnCoCuZnPt) high‐entropy PDH catalyst with high activity and stability. The catalyst exhibited a super high propane conversion of 56.6 % with 94 % selectivity of propylene at 600 °C. The propylene productivity reached 68.5 molC3H6 ⋅ gPt−1 ⋅ h−1, nearly three times that of Pt/SiO2 (23.5 molC3H6 ⋅ gPt−1 ⋅ h−1) under a weight hourly space velocity of 60 h−1. In a high‐entropy nanoparticle, Pt atoms were atomically dispersed through coordination with other metals and exhibited a positive charge, thereby showcasing remarkable catalytic activity. The high‐entropy effect contributes to the catalyst a superior stability with a low deactivation constant of 0.0004 h−1 during 200 hours of reaction under the industrial gas composition at 550 °C. Such high‐entropy PDH catalyst is easy regenerated through simple air combustion of deposited coke. After the fourth consecutive regeneration cycle, satisfactory catalytic stability was observed, and the element distribution of spent catalysts almost returned to their initial state, with no detectable Pt sintering. This work provides new insights into designing active, stable, and regenerable novel PDH catalysts.

Enhancing output performance of triboelectric nanogenerators with ZnFe2O4 nanoparticles in biodegradable polylactic acid for sustainable energy harvesting

ABSTRACT The development of triboelectric nanogenerators (TENGs) using sustainable materials addresses the global electronic waste issue. This research focuses on fabricating a TENG device with biodegradable polylactic acid (PLA) as the tribopositive material and polytetrafluoroethylene (PTFE) as the tribonegative material. ZnFe2O4 nanoparticles are incorporated into the PLA matrix to enhance surface charge density and synthesised via a simple combustion method. PLA-ZnFe2O4 composite films were prepared by solvent casting with varying nanofiller content (0.25, 0.45, 0.65, and 0.85 g). Prepared composites were characterised by Powder X-ray Diffraction (PXRD) for crystalline nature and phase purity, Fourier Transform Infrared Spectroscopy (FTIR) for vibrational analysis, and Scanning Electron Microscopy (SEM) for surface morphology. The inclusion of ZnFe2O4 nanoparticles improves TENG output performance, with a maximum output voltage of 18.4 V and a current of 1.57 µA observed for a PLA (poly(lactic acid)) composite with 39.39% nanoparticle content. Electrical studies on the optimised device show successful charging of various capacitors and powering 20 LEDs and a calculator. Body movements like walking and jumping were also tested to measure voltage and current outputs. These findings highlight new possibilities for developing smart, self-powered electronic devices.

Enhancing low-temperature CO2 methanation performance by selectively covering Ni with CeO2 to form Ni-O-Ce interface active sites

The methanation of CO2 is crucial for resource utilization, however, achieving excellent CO2 methanation performance with Ni-based catalysts at low temperatures remains highly challenging. In this study, a high-performance 10Ni-0.1Ce/Al catalyst was synthesized using a simple and efficient one-pot combustion method. Unlike other catalysts with the same components, this catalyst exhibits a unique feature where a small amount of the CeO2 promoter is dispersed on the support, while the majority selectively binds to and coats the Ni nanoparticles. This distinctive structure allows it to achieve approximately 80 % CO2 conversion and 99.9 % CH4 selectivity under conditions of 260 °C, 0.1 MPa, and a GHSV of 48,000 mL·g−1·h−1. The high catalytic performance is attributed to the unique structure of Ni nanoparticles and CeO2, which promotes the formation of numerous Ni-O-Ce interface active sites. These Ni-O-Ce interfaces enhance the reducibility and increase the content of weak basic sites in the catalyst. The combination of in-situ DRIFTS and TPSR reveals that the decomposition of bridged HCOO– to *CO is the rate-determining step. The presence of Ni-O-Ce interface active sites in the 10Ni-0.1Ce/Al catalyst facilitates the generation of abundant bridged HCOO– intermediates with higher activity than the 10Ni/Al catalyst, leading to a substantial enhancement in catalytic performance.

Enhanced high-rate and long-cycle performance of Mg2+-Al3+ co-doped spinel LiMn2O4 cathode materials for Li-ion batteries

Spinel LiMn2O4 has the potential to be used as a cathode material in lithium-ion batteries because of its affordability, low toxicity, and excellent charge/discharge capability. However, severe capacity attenuation results from the degradation of its long-cycle and high-rate performance caused by the Jahn-Teller distortion and Mn dissolution. Herein, a simple solid-state combustion process is used to successfully prepare the Mg2+-Al3+ co-doped LiMn2O4 with truncated octahedral morphology. The Jahn-Teller distortion is inhibited by the stable Mn-O framework and the decreased lattice constant, which in turn lowers the dissolution of Mn. Moreover, Mg2+-Al3+ co-doped LiMn2O4 have lower activation energy and greater Li+ diffusion coefficient. As a result, the optimized LiMg0.03Al0.10Mn1.87O4 delivers satisfied initial capacity of 102.1 mAh‧g−1 with a capacity retention of 76.2 % after 1000 cycles at 10 C. Even at the ultra-high rate of 15 C and 20 C, Mg2+-Al3+ co-doped sample also remain desired structure stability and cycling performance, which remains 73.8 % of its original capacity after 1000 cycles at 20 C. This work provides a reference for developing high-performance and stability cathode materials for lithium-ion battery.

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.

An Active and Regenerable Nanometric High-Entropy Catalyst for Efficient Propane Dehydrogenation.

Propane dehydrogenation (PDH) is crucial for propylene production, but commercially employed Pt-based catalysts face susceptibility to deactivation due to the Pt sintering during reaction and regeneration steps. Here, we report a SiO2 supported nanometric (MnCoCuZnPt) high-entropy PDH catalyst with high activity and stability. The catalyst exhibited a super high propane conversion of 56.6 % with 94 % selectivity of propylene at 600 °C. The propylene productivity reached 68.5 molC3H6 ⋅ gPt -1 ⋅ h-1, nearly three times that of Pt/SiO2 (23.5 molC3H6 ⋅ gPt -1 ⋅ h-1) under a weight hourly space velocity of 60 h-1. In a high-entropy nanoparticle, Pt atoms were atomically dispersed through coordination with other metals and exhibited a positive charge, thereby showcasing remarkable catalytic activity. The high-entropy effect contributes to the catalyst a superior stability with a low deactivation constant of 0.0004 h-1 during 200 hours of reaction under the industrial gas composition at 550 °C. Such high-entropy PDH catalyst is easy regenerated through simple air combustion of deposited coke. After the fourth consecutive regeneration cycle, satisfactory catalytic stability was observed, and the element distribution of spent catalysts almost returned to their initial state, with no detectable Pt sintering. This work provides new insights into designing active, stable, and regenerable novel PDH catalysts.

A Novel Spinel High-Entropy Oxide (Cr0.2Mn0.2Co0.2Ni0.2Zn0.2)3O4 as Anode Material for Lithium-Ion Batteries

In this study, we synthesized spinel high-entropy oxide (HEO) (Cr0.2Mn0.2Co0.2Ni0.2Zn0.2)3O4 nanoparticles by a simple solution combustion method. These particles were investigated for their performance as anodes in lithium-ion batteries. The reversible capacity is 132 mAh·g−1 after 100 cycles at a current density of 100 mA·g−1, 107 mAh·g−1 after 1000 cycles at a current density of 1 A g−1, and 96 mAh·g−1 rate capacity at a high current density of 2 A g−1. The outstanding cycle stability under high current densities and remarkable rate performance can be attributed to the stable structure originating from the high entropy of the material.

Synthesis and characterisation of calcium-iron-aluminium nanocomposites for electromagnetic radiation shielding application.

Electromagnetic shielding parameters are crucial to investigate unexplored nanoparticles and their nanocomposites. Herein, calcium-iron-aluminium (Ca: Fe: Al) nanocomposites are synthesised using the simple solution combustion technique. The as-synthesised nanocomposites with various doping concentrations of Al nanoparticles are characterised to study the structural and surface parameters and to confirm the successful formation. Further, the procured Ca: Fe: Al nanocomposites along with various doping concentrations are utilised for electromagnetic shielding applications, and various shielding parameters are calculated. It was confirmed that Ca: Fe: Al nanocomposites are suitable for electromagnetic shielding applications.

Combustion behavior of NMP-001, a nitromethane-based green rocket propellant

Hydrazine’s carcinogenic and toxic nature makes its use in space propulsion expensive and necessitates careful launch campaign planning, which may cause delays. One already established alternative is to use energetic salt-based ionic solution propellants. However, the costs remain high because these salts are costly and highly regulated energetic materials. Additionally, propellants based on these energetic salts produce much higher temperatures during decomposition and combustion, as is the case for hydrazine. Consequently, expensive refractory metal-based alloys and high-temperature oxidation-resistant catalytic reactors must be used, which further drives up the costs. Alternatively, hydrogen peroxide may be used, though only in applications with a low specific impulse requirement. This study explores an alternative approach: using nitromethane, a commonly available laboratory solvent. NMP-001 is a nitromethane-based monopropellant that contains additives that allow for low-pressure combustion and reduce sensitivity to mechanical stimuli. Multiple combustion chamber configurations with varying characteristic lengths were tested in rocket combustion experiments. With the 11.5 m L∗-configuration, a 15.1 bar low-pressure limit could be determined. The 7.3 and 5.0 m L∗-configurations yielded a 16.2 and 28.3 bar low-pressure combustion limits, respectively. These outcomes are significantly below the 30 bar limit reported in the literature. Despite using only a simple heat-sink combustion chamber with a non-sophisticated injector element and a non-optimized propellant formulation, combustion was 83 to 95 % efficient with a C* ranged between 1133 to 1302 m/s. These figures are higher than for hydrogen peroxide and are comparable to the theoretical performance of state-of-the-art green liquid monopropellants.

Green synthesis of bismuth vanadate nanostructures for efficient photocatalytic and biological studies

In the current investigation, BiVO4 nanoparticles were prepared via a simple combustion approach followed by annealing at 400°C using rain tree pod extract. The physicochemical and morphological features were examined through spectroscopic techniques. Optical studies were carried out using a UV–visible spectrophotometer, revealing a bandgap of 2.4 eV. Photocatalytic efficiency was assessed through degradation studies using methylene blue (MB) dye under visible photon irradiation, demonstrating an impressive 94 % degradation rate. Consequently, this synthesized bismuth vanadate serves as an outstanding photocatalyst under visible irradiation. Furthermore, these nanoparticles exhibited favorable responses in antifungal, antibacterial, and molecular docking studies. Bismuth vanadate nanoparticles had substantial antifungal efficacy, with the Bi2 version successfully suppressing Aspergillus Niger at a 50 % concentration. At 100 mg/ml, Bi2 showed a 6 mm zone of inhibition against Gram-positive Staphylococcus aureus and a 5 mm zone against Gram-negative Escherichia coli for antibacterial evaluation. The protein 7BLY and Bismuth vanadate had four hydrogen bond interactions and a strong binding affinity, as shown by molecular docking, of −5.0 Kcal/mol. Therefore, bismuth vanadate nanoparticles synthesized through green methods show promise in combating fungal and bacterial infections, as well as potential applications in various fields.

Exploring the diverse performance of nickel and cobalt spinel ferrite nanoparticles in hazardous pollutant removal and gas sensing performance.

A simple sol-gel combustion process was employed for the creation of MFe2O4 (M=Ni, Co) nanoparticles. The synthesized nanoparticles, acting as both photocatalysts and gas sensors, were analyzed using various analytical techniques. MFe2O4 (M=Ni, Co) material improved the degradation of methylene blue (MB) under UV-light irradiation, serving as an enhanced electron transport medium. UV-vis studies demonstrated that NiFe2O4 achieved a 60% degradation, while CoFe2O4 nanostructure exhibited a 76% degradation efficacy in the MB dye removal process. Furthermore, MFe2O4 (M=Ni, Co) demonstrated chemosensitive-type sensor capabilities at ambient temperature. The sensor response and recovery times for CoFe2O4 at a concentration of 100ppm were 15 and 20, respectively. Overall, the synthesis of MFe2O4 (M=Ni, Co) holds the potential to significantly improve the photocatalytic and gas sensing properties, particularly enhancing the performance of CoFe2O4. The observed enhancements make honey MFe2O4 (M=Ni, Co) a preferable choice for environmental remediation applications.

Investigation on the hydrogen production by methanol aqueous phase reforming over Pt/CexMg1-xO2 catalyst: Synergistic effect of support basicity and oxygen vacancies

Green hydrogen production from biomass oxygenated derivatives (methanol, ethanol, ethylene glycol, etc.) by low temperature aqueous phase reforming (APR) has the advantages of high hydrogen selectivity and low energy consumption. A series of CexMg1-xO2 mixed oxide supported catalysts were synthesized by a simple citric acid combustion method. The results show that these catalysts exhibit excellent water-gas shift reaction activity and CO is rarely detected in the products, which is due to their abundant oxygen vacancies of the mixed oxide supports of the Pt/CexMg1-xO2 catalysts. At the same time, the introduction of MgO provides more strong basic sites on the surface of mixed oxide support, and the methanol conversion and hydrogen yield show a volcano peak with the increasing number of basic sites and the hydrogen production reaches the highest (127.16 mmol) over Pt/Ce0·5Mg0·5O2 catalyst. The mixed oxide supported Pt/Ce0·5Mg0·5O2 catalyst enjoys the benefits of both oxygen vacancies in accelerating H2O adsorption/dissociation and strong basic sites in contributing to the formation of formate group (HCOO*), which improve the oxidation of CO* and APR activity. This synergistic effect is conducive to improve hydrogen yield of methanol APR and reduce CO selectivity to a minimum level.

Synergistic engineering of doped Ni2P-Ni12P5 heterostructure electrocatalysts for urea oxidation reaction

Urea oxidation reaction (UOR) is regarded as a potential approach for industrial hydrogen production to address energy scarcity and water pollution challenges. Fabrication of efficient and stable electrocatalysts is a crucial factor in H2 yield and energy conversion efficiency. Herein, we propose a synergistic engineering route to develop the heteroatom-doped Ni2P-Ni12P5 heterojunction on the porous carbon as the electrocatalyst via the simple solution combustion method. The shift of the diffraction peaks, the change of the lattice spacing, and the difference in the electronic distribution indicate that Cu or Mn heteroatoms are successfully doped into the heterojunction Ni2P-Ni12P5 structure, not only promoting the formation of the Ni3+ but also accelerating the electron transfer. As a result, the doping of Cu and Mn into the Ni2P-Ni12P5 heterojunction obtains high-performance electrocatalysts for the UOR. The Mn doping enhances the catalytic performance of the parent Ni2P-Ni12P5 heterostructure, achieving the potential of 1.319 V at 100 mA∙cm−2 in UOR. Moreover, the Cu-doped Ni2P-Ni12P5 heterojunction catalyst shows a low potential of 1.318 V at 100 mA∙cm−2 and demonstrates exceptional long-term stability under different current densities. Notably, when this catalyst is employed in the two-electrode cell for urea-assisted water electrolysis, the hydrogen production readily occurs at the voltage of 1.47 V for reaching 100 mA∙cm−2, manifesting the electrocatalyst with high activity and stability to be a promising candidate for energy-saving electrolytic hydrogen production on the industrial scale.

Fabrication of nickel aluminate based electrochemical sensor for dopamine detection

Nickel aluminate nanoparticles (NiAl2O4 NPs) spinel structure is synthesized via a simple solution combustion method using aqueous nickel nitrate, aluminum nitrate and citric acid. The crystal structure and microstructure of the prepared NiAl2O4 NPs are confirmed by powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectrum, scanning and transmission electron microscopy (SEM/TEM). The characterized NiAl2O4 NPs are applied on a glassy carbon electrode (GCE) to design electrochemical sensor for the detection of dopamine (DA) using cyclic voltammograms (CV) and differential pulse anodic stripping voltammograms. The proposed electrochemical sensor exhibits excellent sensing activity with a low detection limit of 1.78 μM and applicable for a wide linear concentration range of 10 μM–140 μM. Further, the proposed electrode exhibits well resolved differential pulse voltammogram for the dopamine in presence of interfering uric acid and ascorbic acid.

Exploring Potential Applications of α and β Polymorphs of Bi2O3 Nanoparticles

AbstractIn this investigation, we successfully synthesized bismuth oxide (Bi2O3) nanoparticles (NPs) via simple combustion method using Artocarpous heterophyllus (Jackfruit) extract as fuel. Both α and β polymorphs of bismuth oxide NPs was prepared using same Artocarpous heterophyllus fuel but there is a variation in the addition of fuel in the range of 1 mL–6 mL. The prepared NPs were characterized by utilizing spectroscopic techniques. The photocatalytic efficiencies were found to be 84 %, 93 % for both α, β forms respectively. Methylene blue dye exhibits effective degradation for β‐phase compared to α‐phase. Furthermore, Electrochemical impedance spectroscopy and sensing (CV) activities were performed. The bismuth oxide modified electrodes exhibits better sensing activity towards dopamine, ascorbic acid, lead nitrate, and results obtained from EIS data revealed the super capacitor characteristics of Bi2O3 nanoparticles. This extensive investigation assessed the effectiveness of Aspergillus Niger‐fighting drugs, as well as the antibacterial effects of synthesized nanoparticles on Staphylococcus Aureus and Escherichia Coli. Measurements of optical density were used to establish the MIC values for antifungals. The protein 4XUY has a strong binding affinity of −6.4 Kcal/mol, with four important hydrogen bond interactions (LYS51, HIS84, ASN131, and GLU238) revealed by molecular docking research. These results expand our knowledge of the therapeutic uses of bismuth oxide nanoparticles by highlighting their potential as effective antibacterial agents and by providing insightful information about how they work against pathogenic microorganisms.

Novel n–n Type CoCr2O4/NiFe2O4 Heterojunction Photocatalyst: Internal Magnetic Field Control of Photocatalytic Activity, Mechanism Insight and Pathway for Tetracycline Hydrochloride Degradation

AbstractHerein, a series of CoCr2O4/wt%NiFe2O4(CCO/wt%NFO) composites are successfully synthesized by a simple solution combustion method combined with mechanical grinding techniques. The preparation of CCO/wt%NFO composites result in an estimation of its photocatalysis performance by removing tetracycline hydrochloride (TC) as a model of antibiotic pollutants. The results show that the percentage of NFO by mass have a great influence on the morphology and the photocatalysis performance of CCO/wt%NFO composites. Superior photocatalysis performance is observed in CCO/25%NFO composites prepared at percentage of NFO is 25%. The photocatalyst used with CCO/25%NFO composites result in a removal ratio of 81% for TC. The generation of hydroxyl radical (•OH), superoxide anion radical (•O2−) and holes (h+) is largely responsible for degrading TC through photocatalysis in the presence of CCO/wt%NFO composites. The optimal operating conditions involve the initial concentration of TC and pH of TC being 50 mg L−1 and pH = 13, respectively. Furthermore, CCO/wt%NFO is highly reusable and stable during the photocatalytic removal process. The degradation pathway, toxicity, and photocatalytic mechanism of CCO/25%NFO composites for the degradation of TC are extensively examined through mass spectrometry, toxicity analysis, and energy band theory.

High-Entropy Metal Oxide-Coated Carbon Cloth as Catalysts for Long-Life Li-S Batteries.

Lithium-sulfur (Li-S) batteries with high specific energy density, low cost, and environmental friendliness of sulfur have been regarded as a competitive alternative to replace lithium-ion batteries. However, the shuttle effect and the sluggish conversion rate of lithium polysulfides (LiPSs) have seriously limited the practical application of Li-S batteries. Herein, high-entropy oxides grown on the carbon cloth (CC/HEO) are synthesized by a simple and ultrafast solution combustion method for the sulfur cathode. The as-prepared composites possess abundant HEO active sites for strong interaction with LiPSs, which can significantly promote redox kinetics. Besides, the carbon fiber substrate not only ensures high electrical conductivity but also accommodates large volume change, leading to a stable sulfur electrochemistry. Benefiting from the rational design, the Li-S batteries with CC/HEO as cathode skeleton exhibits good cyclability with a capacity decay rate of 0.057% per cycle after 1000 cycles at 2 C. More importantly, the Li-S batteries with 4.3 mg cm-2 high sulfur loading can still retain a high capacity retention of 78.2% after 100 cycles.