Differential Scanning Calorimetry Thermogravimetric Analysis Research Articles

Deciphering Surface Ligand Density of Colloidal Semiconductor Nanocrystals: Shape Matters.

Surface chemistry of colloidal semiconductor nanocrystals (NCs) is of paramount importance because it profoundly impacts their physical and chemical properties, processing, and performance. Herein, we report the effect of the shape of ZnS NCs in terms of nanodots, nanorods, and nanoplatelets (NPL) on the surface ligand density (LD) of the commonly used oleylamine (OLA) ligand by combining three experimental quantification techniques (e.g., thermogravimetric analysis-differential scanning calorimetry, 1H nuclear magnetic resonance spectroscopy, and inductively coupled plasma-optical emission spectrometry) with the semiempirical molecular dynamics (MD) simulations. Consistent results on the surface LD derived by the aforementioned three independent techniques were obtained, presenting an ascending order of LDdots < LDrods < LDNPLs. MD simulations reveal that the highest LD for ZnS NPLs can be attributed to their extremely flat and uniform surfaces with regular distribution of surface Zn atoms for the OLA molecules to achieve parallel and tight stacking, while for ZnS nanodots and nanorods, their surfaces may have staggered arrangement and multisteps, making it unlikely for the OLA ligand to adopt the tight ligand stacking mode. The finding revealed in this work not only sheds light on the constitution of the molecule ligand shell of NCs, which is helpful for their rational morphology control, but also provides an additional and important knob for tuning their chemical functionality.

Synthesis and Performance Evaluation of Zwitterionic C-N Bonded Triazole-Tetrazole-Based Primary Explosives.

Developing advanced metal-free nitrogen-enriched primary explosives is challenging due to the inherent risks associated with their synthesis and handling. However, there is an urgent need to develop novel lead-free, nitrogen-rich primary explosives that offer balanced energetic properties. C-N bonded bicyclic compound 3-azido-1-(1H-tetrazol-5-yl)-1H-1,2,4-triazol-5-amine (4), its salts, and 3,5-diazido-1H-1,2,4-triazole (8) were synthesized from inexpensive starting materials resulting in a fine blend of sensitivity and stability. These compounds exhibit high nitrogen content (79.78 to 83.43%), good thermal stability (129-210 °C), excellent detonation performance (VOD: 8592-9361 ms-1, DP: 27.1-33.8 GPa), and acceptable sensitivity (IS: 2.5-30 J, FS: 72-288 N). The hot needle tests of compounds 4 and 8 exhibit excellent ignition performance. All of the newly synthesized compounds were fully characterized using infrared spectroscopy (IR), high-resolution mass spectroscopy (HRMS), multinuclear magnetic spectroscopy (NMR), elemental analysis (EA), thermogravimetric analysis-differential scanning calorimetry (TGA-DSC), and 2, 4, and 8 were confirmed by single-crystal X-ray crystallographic studies. The molecular electrostatic potential (ESP), noncovalent interactions reduced density gradient (NCI-RDG) method, and QTAIM analysis were performed to investigate the intermolecular interactions. Together with promising performance properties, ease of synthesis, and ignitability, they are highly suitable candidates to pave new avenues for future applications.

The influence of functional groups on the pyrolysis of per- and polyfluoroalkyl substances

Thermal treatment is a widely used remediation strategy for PFAS-contaminated materials such as soil, spent sorbents, and domestic waste. To better understand the effectiveness and environmental impact of thermal treatments for PFAS-contaminated materials, a fundamental understanding of PFAS thermal degradation mechanisms is required. This work aims to study the pyrolysis of six representative PFAS compounds, all of which have an eight-carbon length but with different functional groups. To assess the thermal stability and pyrolysis products of these six PFAS compounds, evolved gas analysis (EGA) was performed using thermogravimetric analysis/differential scanning calorimetry (TGA/DSC) coupled with an infrared spectrometer (IR) and a mass spectrometer (MS), as well as pyrolysis-GCMS (Pyr-GCMS). The EGA data demonstrates that compounds with lower estimated vapor pressures were generally found to be more thermally labile, and the presence of an ionic bond necessitates higher temperatures for pyrolysis. Pyrolysis at 900 °C yielded a variety of fluorinated organic compounds at significant signals. Tetrafluoroethene constituted the majority of the Pyr-GCMS signal for all the compounds. Moreover, a significant fraction of detected products was unable to be identified, underscoring a need for better tools to help with the identification of unknowns. Pyrolysis can occur through random chain scission, scission of the functional group, scission of the terminal CF3 group, and HF elimination. Some compounds may undergo more complete beta-scission to produce smaller pyrolysis products compared to others. The presence of acidic protons within the functional group can help facilitate HF elimination, whereas the salt form of a PFAS compound is less likely to undergo HF elimination. Termination of radical intermediates can either be recombination with a CF3 radical or hydrogen abstraction (H-abstraction). Observed hydrogen-substituted products indicate that functional groups with higher hydrocarbon character may lead to more H-abstraction terminated products. Overall findings show that the functional group of a PFAS may decrease or increase its thermal stability and lead to different profiles of pyrolysis products.

Synthesis of magnesium hydroxide flame retardant based on microcrystalline magnesite and its application in epoxy resin

Abstract A nanoscale hexagonal flake magnesium hydroxide (MH) flame retardant was prepared by a hydrothermal method using Tibetan microcrystalline magnesite as the raw material. The synthesized samples were characterized by x-ray diffraction (XRD), field-emission scanning electron microscopy (FSEM), thermogravimetric analysis-differential scanning calorimetry (TG-DSC), and laser particle size analysis. When subjected to hydrothermal treatment at 180 °C for a duration of 8 h in a solution containing 6 mol l−1 NaOH, and with the incorporation of 4 wt% of the surfactant polyethylene glycol 2000 (PEG2000), hexagonal flake MH, possessing an average particle size of 378.3 nm, was successfully synthesized. The study conducted an examination of the thermal, mechanical, and flame-retardant properties of both EP and EP/MH composites. The results revealed that the incorporation of 9 wt% MH led to a notable reduction in the peak heat release rate, total smoke production, and mass loss rate of the EP/MH composites by 36%, 14.5%, and 33.3% respectively, as compared to the pure EP. Remarkably, the tensile and flexural strength of the composite exhibited minimal impact.

Study on Spontaneous Combustion Characteristics and Microstructure of Bituminous Coal under Water Immersion.

The stagnant water above the coal seam flows into the goaf, causing the goaf coal to be soaked by water for a long time. Compared with dry raw coal, water-soaked coal has a stronger tendency for spontaneous combustion, which poses a serious threat to mining operators. To unravel the impact of water immersion on coal's self-heating properties, an investigation was conducted employing techniques such as simultaneous thermogravimetric analysis/differential scanning calorimetry (TG/DSC), scanning electron microscopy (SEM), low-temperature nitrogen adsorption based on the BET theory, and Fourier transform infrared spectroscopy (FTIR). The variations in the characteristic temperature, microphysical structure, and active functional groups of bituminous coal with water immersion degrees of 10, 30, 50, and 100% were studied, and the experimental results showed that (1) during the initial stage of coal self-ignition oxidation, moisture can cause a delay in the characteristic temperature points of bituminous coal. When the degree of water saturation in bituminous coal reaches 100%, both the critical temperature (T 1) and the cracking temperature (T 2) peak at 48.14 and 205.06 °C, respectively. However, after the water evaporation phase is complete, water soaking promotes the spontaneous combustion of bituminous coal. (2) The number of pores and fractures in bituminous coal is positively correlated with the amount of water soaked, with the average pore diameter increasing from 10.124 nm in raw coal to 15.547 nm in the A4 coal sample. Moreover, when the degree of water immersion reaches 100%, the proportion of mesopores and macropores increases to 38.89 and 19.95%, respectively. (3) Compared to untreated coal, the number of functional groups in water-soaked coal samples increases. With the increase in water immersion, the hydroxyl (-OH) content of raw coal and four kinds of bituminous coal with different degrees of immersion was 40.8, 41.3, 42, 43.9, and 42.9%, respectively, showing a trend of increasing first and then decreasing. When the degree of water immersion of bituminous coal is 50%, the natural tendency is the strongest. These findings contribute to elucidating the underlying mechanism of water immersion's impact on coal self-ignition, thereby holding significant implications for enhancing fire safety measures in mine working areas.

Symmetric Refunctionalization of Diaminodinitropyrazine with Hydrazine and Aminotetrazole: Strategy for Enhancing Detonation Performance and Safety in Energetic Materials.

Two novel nitrogen-rich green energetic compounds were synthesized for the first time from readily available and cost-effective pyrazine starting materials. All newly synthesized molecules were comprehensively characterized, including infrared spectroscopy, nuclear magnetic resonance, elemental analysis, mass spectrometry, and thermogravimetric analysis-differential scanning calorimetry. All compounds have additionally been validated by single-crystal X-ray diffraction analysis. The physicochemical properties of compounds 2, 4, and 5 were thoroughly investigated. Notably, all compounds exhibit remarkable performance, such as a high density (>1.84 g cm-3), excellent detonation properties (VOD > 8582 m s-1, and DP > 31.3 GPa), outstanding thermostability (>205 °C), and high insensitivity (IS > 35 J, and FS = 360 N). These attributes are quite comparable to those of secondary benchmark explosives such as TATB, RDX, LLM-105, and FOX-7. This tuned performance evidences that the incorporation of hydrazine, nitro, and aminotetrazole into the pyrazine framework fosters robust nonbonded interactions, ultimately enhancing thermal stability and reducing sensitivity. The findings of this study not only signify that compounds 2 and 5 have excellent detonation properties and stability but also prove that the strategy of replacing amino groups with hydrazine and aminotetrazole is a practical means of developing new insensitive energetic materials.

Nano silicated-FeAl2O4 functionalized by DL-alaninium nitrate ionic liquid (FeAl2O4-SiO2@[DL-Ala][NO3]) as versatile promotor for aqua-mediated synthesis of spiro[chromenopyrazole-indene-triones and spiro[chromenopyrazole-indoline-diones

In this work, the spinel FeAl2O4 was prepared and functionalized step-by-step with silica and alaninium nitrate ionic liquid ([DL-Ala][NO3]) to produce a bio-based multi-layered nanostructure (nano FeAl2O4-SiO2@[DL-Ala][NO3]). The obtained magnetized inorganic-bioorganic nanohybrid characterized by Fourier transform infrared spectroscopy (FT-IR), vibrating-sample magnetometry (VSM), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDAX), transmission electron microscopy (TEM), thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), X-ray fluorescence (XRF), and X-Ray diffraction (XRD) analysis. A facile synthesis of some tricyclic dihydro-spiro[chromeno[2,3-c]pyrazole-4,2′-indene]triones and dihydro-spiro[chromeno[2,3-c]pyrazole-4,3′-indoline]diones via domino four-component one-pot reaction of various hydrazine derivatives, ethyl acetoacetate, heterocyclic 1,2-ketones (ninhydrin, isatin, 5-bromoisatin) and cyclic 1,3-diketones (dimedone and 1,3-cyclohexanedine), examined in the presence of nano FeAl2O4-SiO2@[DL-Ala][NO3] nanohybrid in refluxing aqueous media, successfully. The multi-aspect characteristics of the nanohybrid which consist of magnetized inorganic and bioorganic parts, could be the reason of its special catalytic efficacy. The recovery and reusability of the FeAl2O4-SiO2@[DL-Ala][NO3] magnetized nanoparticles (MNPs) were performed in two runs without significant activity loss.

Green synthesis of silver nanoparticles and their application for colorimetric detection of L-cysteine: a spectroscopic investigation

In this study, we report an eco-friendly synthesis of silver nanoparticles (AgNPs) using banana peel extract (BPE), along with their use for colorimetric detection of L-cysteine and investigation of the mechanisms involved in these processes. Transmission electron microscopy (TEM) and UV–Vis spectroscopy were used to confirm the formation of silver particles at the nanoscale (∼20 nm). TEM images also showed the presence of BPE-derived organic material enveloping the nanoparticles. The nature and role of this capping material were investigated by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis/differential scanning calorimetry (TGA/DSC). Visual inspection and UV–Vis spectroscopy revealed that the insertion of L-cysteine into the AgNPs solutions induced discernible color changes. pH variations in the solutions and FTIR spectroscopy were also employed to study the molecular dynamics underlying the formation of AgNPs, the capping material and the detection of L-cysteine. Studies concerning different amino acids in AgNPs solutions confirmed the selectivity for L-cysteine. The overall spectroscopic results, particularly those from FTIR spectroscopy, shed light on the crucial role of carboxylate ions (COO–) of BPE in the formation of AgNPs and their interaction with L-cysteine. Finally, the importance of the thiol group of L-cysteine in the colorimetric detection process was also reinforced by this study.

Influence of Crucible Types on Thermal Stability Analysis of Li‐Ion Battery Components by Thermogravimetric Analysis–Differential Scanning Calorimetry

Lithium‐ion batteries are widely used in various industrial and consumer applications. One key point is the thermal stability of these batteries regarding safety. Thermogravimetric analysis and differential scanning calorimetry (DSC) are ideal methods to study the thermal properties of differently charged electrode materials without safety issues associated with thermal runaway tests of the complete cell. This study shows a significant relationship between state of charge (SOC) and power released by the electrode material during the heating process. For the utilized cathode material LixCoO2, a linear relationship is apparent between the decomposition temperature and the decomposition energy, enabling estimation of the SOC. The decomposition temperature of differently charged anode material strongly correlates with the selected heating rate. This study reveals substantial dependencies of the measured power on the utilized crucibles, providing a systematic approach to benchmark the impact of crucible type on observed DSC signals during battery component analysis.

Elaborating NH-Bridged Nitrogen-Rich Energetic Materials via Base-Mediated Dimroth Rearrangement: Synthesis, Characterization, and Performance Study.

The pursuit of heat-resistant energetic materials featuring high thermostability and energy has gained keen interest in recent years owing to their use in coal mining and aerospace domains. In this study, we synthesized 4-((4,6-diamino-1,3,5-triazin-2-yl) amino)-1H-1,2,3-triazole-5-carbonitrile (6) and its perchlorate and nitrate energetic salts (6a and 6b) by incorporating amino bridging (-NH-) using the Dimroth rearrangement (DR) from inexpensive starting materials as a heat-resistant energetic materials. All of the compounds were thoroughly characterized by infrared (IR), NMR, elemental analysis (EA), high-resolution mass spectrometry (HRMS), and thermogravimetric analysis-differential scanning calorimetry (TGA-DSC) studies. Compounds 6a and 6b showed good densities (1.81 and 1.80 g cm-3), detonation performance (VOD = 7505 and 8257 m s-1, DP = 23.47 and 24.41 GPa), insensitivity to mechanical stimuli (IS = 40 J and FS = >360 N), and excellent thermal stability (Td = 307 and 334 °C), surpassing presently used heat-resistant explosive HNS (318 °C). The molecular electrostatic potentials and noncovalent interactions were pursued to understand possible interaction sites and structure-directing interactions in these salts. Their facile synthetic approach, good energetic performance, and outstanding thermal stability indicate that they are the ideal combination for replacing current benchmark heat-resistant explosive HNS. Additionally, this study highlights the use of classical DR for making new energetic materials with fine-tuned properties.

Synthesis, characterization and structural analysis of complexes from 2,2':6',2''-terpyridine derivatives with transition metals.

The synthesis and structural characterization of three families of coordination complexes synthesized from 4'-phenyl-2,2':6',2''-terpyridine (8, Ph-TPY), 4'-(4-chlorophenyl)-2,2':6',2''-terpyridine (9, ClPh-TPY) and 4'-(4-methoxyphenyl)-2,2':6',2''-terpyridine (10, MeOPh-TPY) ligands with the divalent metals Co2+, Fe2+, Mn2+ and Ni2+ are reported. The compounds were synthesized from a 1:2 mixture of the metal and ligand, resulting in a series of complexes with the general formula [M(R-TPY)2](ClO4)2 (where M= Co2+, Fe2+, Mn2+ and Ni2+, and R-TPY= Ph-TPY, ClPh-TPY and MeOPh-TPY). The general formula and structural and supramolecular features were determinated by single-crystal X-ray diffraction for bis(4'-phenyl-2,2':6',2''-terpyridine)nickel(II) bis(perchlorate), [Ni(C21H15N3)2](ClO4)2 or [Ni(Ph-TPY)2](ClO4)2, bis[4'-(4-methoxyphenyl)-2,2':6',2''-terpyridine]manganese(II) bis(perchlorate), [Mn(C22H17N3O)2](ClO4)2 or [Mn(MeOPh-TPY)2](ClO4)2, and bis(4'-phenyl-2,2':6',2''-terpyridine)manganese(II) bis(perchlorate), [Mn(C21H15N3)2](ClO4)2 or [Mn(Ph-TPY)2](ClO4)2. In all three cases, the complexes present distorted octahedral coordination polyhedra and the crystal packing is determined mainly by weak C-H...π interactions. All the compounds (except for the Ni derivatives, for which FT-IR, UV-Vis and thermal analysis are reported) were fully characterized by spectroscopic (FT-IR, UV-Vis and NMR spectroscopy) and thermal (TGA-DSC, thermogravimetric analysis-differential scanning calorimetry) methods.

Synthesis of Cu-MOF-derived complex copper–chromium oxides and their catalytic study on the thermal decomposition of ammonium perchlorate

In this work, a series of complex copper-chromium oxides were prepared by adjusting the molar ratio of Cr3+/Cu2+ using MOF-199 as a template. X-ray diffraction (XRD), scanning electron microscopy (SEM), Transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the structure, microscopic morphology and valence information of the samples. The specific surface area of the sample was estimated by the Brunauer-Emmett-Teller method (BET), and the pore size parameters of the sample were obtained by using the Barrett-Joyner-Halenda (BJH) model. The effect of the samples on the thermal decomposition process of ammonium perchlorate (AP) was investigated by differential scanning calorimetry-thermogravimetric analysis. The results show that the copper and chromium oxides in the complex exhibit good catalytic effects. Among them, CuCr(0.8) had the best catalytic effect, reducing the peak pyrolysis temperature of AP by 95.7 °C, increasing the heat release by 817 J/g, and reducing the reaction activation energy by 62.4 kJ/mol. Real-time FTIR was used to characterize the gas products during the thermal decomposition of AP, and the gas products of AP with CuCr(0.8) catalyst were different from those of pure AP, which may also be the reason for the increase of AP heat release after adding CuCr(0.8) catalyst.

Trinitromethyl-Substituted 1H-1,2,4-Triazole Bridging Nitropyrazole: A Strategy of Utterly Manipulable Nitration Achieving High-Energy Density Material.

Nitro groups have been demonstrated to play a decisive role in the development of the most powerful known energetic materials. Two trinitromethyl-substituted 1H-1,2,4-triazole bridging nitropyrazoles were first synthesized by straightforward routes and were characterized by chemical (MS, NMR, IR spectroscopy, and single-crystal X-ray diffraction) and experimental analysis (sensitivity toward friction, impact, and differential scanning calorimetry-thermogravimetric analysis test). Their detonation properties (detonation pressure, detonation velocity, etc.) were predicted by the EXPLO5 package based on the crystal density and calculated heat of formation with Gaussian 09. These new trinitromethyl triazoles were found to show suitable sensitivities, high density, and highly positive heat of formation. The combination of exceedingly high performances superior to those of HMX (1,3,5,7-tetranitrotetraazacyclooctane), and its straightforward preparation highlights compound 8 as a promising high-energy density material (HEDM). This work supports the effectivity of utterly manipulable nitration and provides a generalizable design synthesis strategy for developing new HEDMs.

Kinetic Analysis of the Reaction of Micrometer-Sized Al-Mg Alloy Particles in a Water Vapor Atmosphere.

This study investigated the reaction mechanism of aluminum-magnesium (Al-Mg) alloy particles with water (Al-Mg/H2O) through thermogravimetric analysis-differential scanning calorimetry experiments and kinetic analysis using isoconversional methods and the master plot technique to determine the reaction mechanism function, with the aim of providing insights to support metal powder/water ramjet engine design and combustion characteristics. The results showed that the Al-Mg/H2O reaction occurred in two distinct stages, with stage 1 primarily involving the reaction of Mg elements in the L(Al-Mg) alloy with water while Al played a leading role in stage 2. Notably, the reaction temperatures of Al-Mg particles were significantly lower than those for either Al or Mg particles alone in a water vapor environment. Additionally, the activation energy of stage 1 was lower than that for the individual Al and Mg particles and decreased with increasing Mg content in stage 2. Furthermore, the concentration of Mg in the alloy was found to have a major influence on the reaction mechanism, which followed a random nucleation and growth model. Overall, this work elucidated an alternating endothermic and exothermic staged reaction process for Al-Mg/H2O dominated first by Mg and then Al with kinetic insights providing theoretical support for optimizing Al-Mg alloy compositions for improved ignition and combustion performance in metal powder/water ramjet engines.

Research on the inerting mechanism of sucrose dust explosion by sodium bicarbonate

Sucrose dust is prone to explosion accidents during the production process. This research utilized sodium bicarbonate (NaHCO3) to prevent the explosion of sucrose dust. Based on the minimum ignition temperature of sucrose dust cloud (MITc), combined with thermogravimetric analysis-differential scanning calorimetry (TG-DSC) and pyrolysis-gas chromatography-mass spectrometry (PY-GCMS), the differences of combustion processes and combustion products between sucrose dust and sucrose-NaHCO3 mixed dust were comprehensively compared. Also, the mechanisms of sucrose dust explosion and NaHCO3 inerting sucrose dust were systematically studied. It showed that NaHCO3 powder contributed to a higher MITc of sucrose dust and activation energy of sucrose oxidation reaction, with a reduction in exothermic enthalpy and entropy changes. NaHCO3 interfered with the entire burning process of sucrose dust by playing an important role in physical inhibition, and producing sodium-containing compounds to capture free radicals from the bond breakage of sucrose. It limits the reaction pathway and progress of sucrose pyrolysis and therefore against burning. Additionally, the mass fraction and particle size of NaHCO3 impact the inerting ability by increasing the amount and accelerating the procedure rate of products, respectively. The increase in mass fraction works better in macroscopic phenomena, while the decrease in particle size is more significant in reaction kinetics and thermodynamic parameters.

Fabrication of Al@AIH@PVDF metastable composite film with enhanced laser ignition ability and combustion performance

Laser ignition technology has garnered significant attention for energetic materials in recent years, offering advantages over traditional electrical initiation methods, notably in mitigating issues related to stray currents and electromagnetic interference. Moreover, it can facilitate multi-point synchronous ignition. However, the persistent challenges of high ignition thresholds and delays in energetic materials necessitate effective resolutions. In this study, we address these challenges by converting the inert Al2O3 layer on the surface of aluminum powder into the active compound Aluminum Iodate Hexahydrate ([Al(H2O)6](IO3)3(HIO3)2, AIH) to prepare an Al@AIH@PVDF energetic composite film (ECF) with the aim of reducing the laser ignition threshold and delay of Al@PVDF ECF. The Al@AIH@PVDF ECF was synthesized through a simple wet chemistry method and a rapid evaporation process suing a simple, environmental-friendly, and cost-effective way. Differential scanning calorimetry-thermogravimetric analysis (DSC-TG) results demonstrate a lower exothermic reaction temperature (161 °C) and higher heat release (2900 J g−1) for Al@AIH@PVDF ECF. Laser ignition tests reveal a reduced laser ignition delay (11 ms) and threshold (1.59 J cm−2) for Al@AIH@PVDF ECF. Combustion experiments showcase elevated combustion flame temperature (3090 K), burning rate (4.11 cm s−1), and smaller condensed combustion products, while effectively igniting CL-20. Pressure tests indicate higher maximum combustion pressure (3.24 MPa) and pressure rise rate (4.05 GPa s−1) for Al@AIH@PVDF ECF. Finally, the reaction process and mechanism of Al@AIH@PVDF ECF was also investigated and proposed.

Tin-antimony/carbon composite porous fibers: electrospinning synthesis and application in sodium-ion batteries

In this work, tin-antimony/carbon composites porous fibers were successfully synthesized by an electrospinning method combined with two-step heat treatment processes, in which SnCl2 and SbCl3 were used as tin and antimony sources, and polyacrylonitrile (PAN) and polymethyl methacrylate (PMMA) were used as binders and pore-forming agents. The as-synthesized tin-antimony/carbon composites were systematically characterized by x-ray Diffraction (XRD), Transmission Electron Microscope (TEM), Scanning Electron Microscope (SEM), Energy-Dispersive Spectrometer (EDS), x-ray Photoelectron Spectroscopy (XPS), and Thermogravimetric Analysis-Differential Scanning Calorimetry (TG-DSC). The results indicate that the composite material consists of one-dimensional nitrogen-doped carbon porous fibers as the main matrix, with a three-dimensional network structure in which Sn, SnO2, and SnSb particles are encapsulated. Furthermore, the tin-antimony/carbon composites porous fibers were utilized as self-supported negative electrode for sodium-ion batteries. The results showed that the SNbM-2 sample electrode calcined at 800 °C demonstrated the best cycling stability and rate capability among all the sample electrodes, with a discharge capacity of 319.5 mAh·g−1 maintained after 100 cycles at a current density of 0.1 A·g−1. The excellent electrochemical performance of the SNbM-2 sample electrode is benefited from its unique porous structure and the carbon fiber network structure encapsulating Sn, SnO2, and SnSb particles, which could effectively shorten the Na+ ion transport distance and mitigate electrode volume expansion.

Pozzolanic performance and characteristic analysis of binary blended cement incorporating ceramic polishing sludge

The waste generated during ceramic polishing is typically disposed of in landfills rather than being recycled within the production facility, potentially causing environmental harm. This study aims to enhance industrial waste utilization and reduce CO2 emissions in the cement industry by investigating the feasibility of incorporating ceramic sludge from polishing processes into an innovative binary blended cement. Different binders were prepared with varying amounts of ceramic polishing sludge (CPS), ranging from 10% to 50%, and tested against the ASTM C595 standards. The results were compared with those of ordinary Portland cement (OPC). This approach involves evaluating the pozzolanic activity and conducting an advanced characterization assessment of CPS and binary blended ceramic polishing sludge cement (CPSC) paste. This study employed a combination of physical, mechanical, and chemical tests, including setting time, particle size distribution (PSD), Brunauer-Emmett-Teller (BET) specific surface area, compressive strength, X-ray diffraction (XRD), scanning electron microscopy (SEM), heat of hydration, and differential scanning calorimetry/thermogravimetric analysis (DSC/TGA). The results indicated that CPS can be used as a pozzolanic material to create innovative binders with properties comparable to those of OPC. The Strength Activity Index (SAI) values affirmed the pozzolanic properties of CPS, exceeding 75% for up to 40% CPS replacement. Incorporating CPS in the blended cement resulted in a slower rate of cement hydration, leading to prolonged setting times and reduced early strength development. Although the compressive strength decreased with increasing CPS content, it remained within the acceptable ASTM C595 limits with up to 50% replacement. Nevertheless, the optimal replacement level of OPC with CPS was determined to be 50%. Furthermore, CPS substitution reduced the dry density and improved the water absorption and apparent porosity, reflecting microstructural changes. The SEM images revealed that the blended CPSC had a lower apparent porosity than the pure OPC. The DSC/TGA analysis demonstrated that the blended cement had a lower calcium hydroxide content and higher silica than pure OPC.

Facile synthesis and physical properties of magnesium dititanate nanoparticles for antibacterial applications

AbstractThe modified aqueous co-precipitation approach was used to successfully manufacture magnesium dititanate (MgTi2O5) nanoparticles. Thermogravimetric analysis/differential scanning calorimetry (TG/DSC) was used to clearly reveal the thermal stability. Moreover, pseudobrookite structure, and surface morphology of MgTi2O5 nanoparticles were determined using X-ray diffraction (XRD), transmission electron microscope (TEM), and Fourier-transform infrared (FT-IR), and scanning electron microscope (SEM) techniques, respectively. The average size of the crystallites calculated by Scherer approach was compared to Williamson-Hall and TEM images results. The optical band gap of MgTi2O5 nanoparticles was found to be 3.81 eV for direct transitions. The effect of temperature on the conductivity of DC electricity was tested between the rages 303–503 K. The data on antibacterial activity showed that MgTi2O5 nanoparticles were antimicrobial and stopped the test microorganisms from growing. These findings revealed that MgTi2O5 will be extensively promising in environmental pollution control and antibacterial research.

Impact of preparation methods on the performance of Cu/Ni/Zr catalysts for methanol decomposition

Utilizing waste heat from engine exhausts to decompose methanol into a hydrogen (H2) and carbon monoxide (CO) mixture, subsequently reintroduced into the engine, offers a significant potential to enhance engine efficiency and reduce emissions. The efficacy of the catalyst is crucial, as it directly influences the composition of the decomposition gases, thereby impacting energy conservation and emissions reduction. This study investigates the impact of various preparation methods for the self-developed Cu/Ni/Zr catalyst for methanol hydrogenation decomposition. These techniques include the co-precipitation method, co-impregnation method, and citrate complexation method, evaluated within a temperature spectrum of 220 °C–320 °C. Employing analytical methods such as x-ray Photoelectron Spectroscopy (XPS), x-ray Diffraction (XRD), Thermogravimetric Analysis-Differential Scanning Calorimetry (TGA-DSC), Brunauer–Emmett–Teller (BET), Temperature-Programmed Reduction (TPR), and Scanning Electron Microscopy (SEM) analysis, the study elucidates the mechanism of methanol decomposition catalyzed by Cu/Ni/Zr. The findings indicate that the catalyst’s activity, in terms of decomposition rate and hydrogen content, ranks in descending order from the co-impregnation method, followed by the citrate complexation method, to the co-precipitation method.