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Keywords = decomposition reaction products

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26 pages, 5455 KiB  
Article
Features of Thermal Stabilization of PVC Modified with Microstructured Titanium Phosphate
by Irina N. Vikhareva, Anton Abramian, Dragan Manojlović and Oleg Bol’shakov
Polymers 2025, 17(15), 2140; https://doi.org/10.3390/polym17152140 - 5 Aug 2025
Abstract
Poly(vinyl chloride) (PVC) undergoes thermal degradation during processing and operation, which necessitates the use of effective thermal stabilizers. The purpose of this work is to comprehensively evaluate the potential of new hierarchically structured titanium phosphates (TiP) with controlled morphology as thermal stabilizers of [...] Read more.
Poly(vinyl chloride) (PVC) undergoes thermal degradation during processing and operation, which necessitates the use of effective thermal stabilizers. The purpose of this work is to comprehensively evaluate the potential of new hierarchically structured titanium phosphates (TiP) with controlled morphology as thermal stabilizers of plasticized PVC, focusing on the effect of morphology and Ti/P ratio on their stabilizing efficiency. The thermal stability of the compositions was studied by thermogravimetric analysis (TGA) in both inert (Ar) and oxidizing (air) atmospheres. The effect of TiP concentration and its synergy with industrial stabilizers was analyzed. An assessment of the key degradation parameters is given: the temperature of degradation onset, the rate of decomposition, exothermic effects, and the carbon residue yield. In an inert environment, TiPMSI/TiPMSII microspheres demonstrated an optimal balance by increasing the temperature of degradation onset and the residual yield while suppressing the rate of decomposition. In an oxidizing environment, TiPR rods and TiPMSII microspheres provided maximum stability, enhancing resistance to degradation onset and reducing the degradation rate by 10–15%. Key factors of effectiveness include ordered morphology (spheres, rods); the Ti-deficient Ti/P ratio (~0.86), which enhances HCl binding; and crystallinity. The stabilization mechanism of titanium phosphates is attributed to their high affinity for hydrogen chloride (HCl), which catalyzes PVC chain scission, a catalyst for the destruction of the PVC chain. The unique microstructure of titanium phosphate provides a high specific surface area and, as a result, greater activity in the HCl neutralization reaction. The formation of a sol–phosphate framework creates a barrier to heat and oxygen. An additional contribution comes from the inhibition of oxidative processes and the possible interaction with unstable chlorallyl groups in PVC macromolecules. Thus, hierarchically structured titanium phosphates have shown high potential as multifunctional PVC thermostabilizers for modern polymer materials. Potential applications include the development of environmentally friendly PVC formulations with partial or complete replacement of toxic stabilizers, the optimization of thermal stabilization for products used in aggressive environments, and the use of hierarchical TiP structures in flame-resistant and halogen-free PVC-based compositions. Full article
(This article belongs to the Section Polymer Processing and Engineering)
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18 pages, 3967 KiB  
Article
A Thorough Investigation of the Mechanism of theAntagonistic Effect Between Phosphorus and Basic Oxide-Forming Minerals as Flame Retardants of PolymericComposite Coatings
by Evangelia Mitropoulou, Georgios N. Mathioudakis, Amaia Soto Beobide, Athanasios Porfyris, Vassilios Dracopoulos, Kerim Kılınç, Theodosios Chatzinikolaou, Deniz Savci, Cem Gunesoglu, Joannis Kallitsis and George A. Voyiatzis
Coatings 2025, 15(8), 886; https://doi.org/10.3390/coatings15080886 - 30 Jul 2025
Viewed by 232
Abstract
Halogenated flame retardants have been amongst the most widely used and effective solutions for enhancing fire resistance. However, their use is currently strictly regulated due to serious health and environmental concerns. In this context, phosphorus-based and mineral flame retardants have emerged as promising [...] Read more.
Halogenated flame retardants have been amongst the most widely used and effective solutions for enhancing fire resistance. However, their use is currently strictly regulated due to serious health and environmental concerns. In this context, phosphorus-based and mineral flame retardants have emerged as promising alternatives. Despite this, their combined use is neither straightforward nor guaranteed to be effective. This study scrutinizes the interactions between these two classes of flame retardants (FR) through a systematic analysis aimed at elucidating the antagonistic pathways that arise from their coexistence. Specifically, this study focuses on two inorganic fillers, mineral huntite and chemically precipitated magnesium hydroxide, both of which produce basic oxides upon thermal decomposition. These fillers were incorporated into a poly(butylene terephthalate) (PBT) matrix to be utilized as advanced-mattress FR coating fabric and were subjected to a series of flammability tests. The pyrolysis products of the prepared polymeric composite compounds were isolated and thoroughly characterized using a combination of analytical techniques. Thermogravimetric analysis (TGA) and differential thermogravimetric analysis (dTGA) were employed to monitor decomposition behavior, while the char residues collected at different pyrolysis stages were examined spectroscopically, using FTIR-ATR and Raman spectroscopy, to identify their structure and the chemical reactions that led to their formation. X-ray diffraction (XRD) experiments were also conducted to complement the spectroscopic findings in the chemical composition of the resulting char residues and to pinpoint the different species that constitute them. The morphological changes of the char’s structure were monitored by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). Finally, the Limited Oxygen Index (LOI) and UL94 (vertical sample mode) methods were used to assess the relative flammability of the samples, revealing a significant drop in flame retardancy when both types of flame retardants are present. This reduction is attributed to the neutralization of acidic phosphorus species by the basic oxides generated during the decomposition of the basic inorganic fillers, as confirmed by the characterization techniques employed. These findings underscore the challenge of combining organophosphorus with popular flame-retardant classes such as mineral or basic metal flame retardants, offering insight into a key difficulty in formulating next-generation halogen-free flame-retardant composite coatings. Full article
(This article belongs to the Special Issue Innovative Flame-Retardant Coatings for High-Performance Materials)
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16 pages, 2285 KiB  
Article
Evaluating the Heat of Hydration, Conductivity, and Microstructural Properties of Cement Composites with Recycled Concrete Powder
by Damir Barbir, Pero Dabić, Miće Jakić and Ivana Weber
Buildings 2025, 15(15), 2613; https://doi.org/10.3390/buildings15152613 - 23 Jul 2025
Viewed by 204
Abstract
This study investigates the effects of incorporating recycled concrete powder (RCP) as a supplementary cementitious material in Portland cement composites at replacement levels of 5–30% by weight. A comprehensive characterization using isothermal calorimetry, electrical conductivity measurements, thermogravimetric analysis, FT-IR spectroscopy, and scanning electron [...] Read more.
This study investigates the effects of incorporating recycled concrete powder (RCP) as a supplementary cementitious material in Portland cement composites at replacement levels of 5–30% by weight. A comprehensive characterization using isothermal calorimetry, electrical conductivity measurements, thermogravimetric analysis, FT-IR spectroscopy, and scanning electron microscopy revealed that RCP modified the hydration behavior and microstructural development. The results showed a linear 16.5% reduction in the total heat of hydration (from 145.38 to 121.44 J/g) at 30% RCP content, accompanied by a 26.5% decrease in peak electrical conductivity (19.16 to 14.08 mS/cm) and delayed reaction kinetics. Thermal analysis demonstrated an increased stability of hydration products, with portlandite decomposition temperatures rising by up to 10.8 °C. Microstructural observations confirmed the formation of denser but more amorphous C–S–H phases alongside increased interfacial porosity at higher RCP contents. The study provides quantitative evidence of RCP’s dual functionality as both an inert filler and a nucleation agent, identifying an optimal 20–25% replacement range that balances performance and sustainability. These findings advance the understanding of construction waste utilization in cementitious materials and provide practical solutions for developing more sustainable building composites while addressing circular economy objectives in the construction sector. Full article
(This article belongs to the Special Issue Advances and Applications of Recycled Concrete in Green Building)
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16 pages, 2458 KiB  
Article
Kinetics of H2O2 Decomposition and Bacteria Inactivation in a Continuous-Flow Reactor with a Fixed Bed of Cobalt Ferrite Catalyst
by Nazarii Danyliuk, Viktor Husak, Volodymyra Boichuk, Dorota Ziółkowska, Ivanna Danyliuk and Alexander Shyichuk
Appl. Sci. 2025, 15(15), 8195; https://doi.org/10.3390/app15158195 - 23 Jul 2025
Viewed by 209
Abstract
As a result of the catalytic decomposition of H2O2, hydroxyl radicals are produced. Hydroxyl radicals are strong oxidants and effectively inactivate bacteria, ensuring water disinfection without toxic chlorinated organic by-products. The kinetics of bacterial inactivation were studied in a [...] Read more.
As a result of the catalytic decomposition of H2O2, hydroxyl radicals are produced. Hydroxyl radicals are strong oxidants and effectively inactivate bacteria, ensuring water disinfection without toxic chlorinated organic by-products. The kinetics of bacterial inactivation were studied in a laboratory-scale flow catalytic reactor. A granular cobalt ferrite catalyst was thoroughly characterized using XRD and XRF techniques, SEM with EDS, and Raman spectroscopy. At lower H2O2 concentrations, H2O2 decomposition follows first-order reaction kinetics. At higher H2O2 concentrations, the obtained kinetics lines suggest that the reaction order increases. The kinetics of bacterial inactivation in the developed flow reactor depends largely on the initial number of bacteria. The initial bacterial concentrations in laboratory tests were within the range typical of real river water. A regression model was developed that relates the degree of bacterial inactivation to the initial number of bacteria, the initial H2O2 concentration, and the contact time of water with the catalyst. Full article
(This article belongs to the Special Issue Water Pollution and Wastewater Treatment Chemistry)
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9 pages, 798 KiB  
Article
Mechanistic Behavior of Basicity of Bimetallic Ni/ZrO2 Mixed Oxides for Stable Oxythermal Reforming of CH4 with CO2
by Hyuk Jong Bong, Nagireddy Gari Subba Reddy and A. Geetha Bhavani
Catalysts 2025, 15(8), 700; https://doi.org/10.3390/catal15080700 - 22 Jul 2025
Viewed by 345
Abstract
The mixed oxides of Ni/ZrO2, Ni-Ca/ZrO2, Ni-Ba/ZrO2, and Ni-Ba-Ca/ZrO2 were prepared using the co-precipitation method at a pH of precisely 8.3. The catalytic mixed oxides of Ni/ZrO2, Ni-Ca/ZrO2, Ni-Ba/ZrO2, and [...] Read more.
The mixed oxides of Ni/ZrO2, Ni-Ca/ZrO2, Ni-Ba/ZrO2, and Ni-Ba-Ca/ZrO2 were prepared using the co-precipitation method at a pH of precisely 8.3. The catalytic mixed oxides of Ni/ZrO2, Ni-Ca/ZrO2, Ni-Ba/ZrO2, and Ni-Ba-Ca/ZrO2 were characterized using x-ray diffraction XRD, Brunauer Emmett Teller (BET), scanning electron microscopy (SEM), and metal dispersion for the screening of phase purity, surface area, and morphology. The mixed oxides are subjected to CO2-TPD to quantify the basicity of every composition. The mixed oxide catalysts of Ni/ZrO2, Ni-Ca/ZrO2, Ni-Ba/ZrO2, and Ni-Ba-Ca/ZrO2 were screened for oxythermal reforming of CH4 with CO2 in a fixed bed tubular reactor at 800 °C. Among all catalysts, the Ba- and Ca- loaded Ni-Ba-Ca/ZrO2 showed high conversion by the decomposition of methane and CO2 disproportionation throughout the time on stream of 29 h. The high activity with stability led to less coke formation over Ni-Ba-Ca/ZrO2 over the surface. The stable syngas production with an active catalyst bed contributed to the improved bimetallic synergy. The high surface basicity of Ni-Ba-Ca/ZrO2 may keep actively gasifying the formed soot and allow for further stable reforming reactions. Full article
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11 pages, 2972 KiB  
Article
ZnCu Metal–Organic Framework Electrocatalysts for Efficient Ammonia Decomposition to Hydrogen
by Mingguang Ouyang, Geng Chen, Weitao Ning, Xiaoyang Wang, Xiaojiang Mu and Lei Miao
Energies 2025, 18(14), 3871; https://doi.org/10.3390/en18143871 - 21 Jul 2025
Viewed by 323
Abstract
The electrocatalytic decomposition of ammonia represents a promising route for sustainable hydrogen production, yet current systems rely heavily on noble metal catalysts with prohibitive costs and limited durability. A critical challenge lies in developing non-noble electrocatalysts that simultaneously achieve high active site exposure, [...] Read more.
The electrocatalytic decomposition of ammonia represents a promising route for sustainable hydrogen production, yet current systems rely heavily on noble metal catalysts with prohibitive costs and limited durability. A critical challenge lies in developing non-noble electrocatalysts that simultaneously achieve high active site exposure, optimized electronic configurations, and robust structural stability. Addressing these requirements, this study strategically engineered Cu-doped ZIF-8 architectures via in situ growth on nickel foam (NF) substrates through a facile room-temperature hydrothermal synthesis approach. Systematic optimization of the Cu/Zn molar ratio revealed that Cu0.7Zn0.3-ZIF/NF achieved optimal performance, exhibiting a distinctive nanoflower-like architecture that substantially increased accessible active sites. The hybrid catalyst demonstrated superior electrocatalytic performance with a current density of 124 mA cm−2 at 1.6 V vs. RHE and a notably low Tafel slope of 30.94 mV dec−1, outperforming both Zn-ZIF/NF (39.45 mV dec−1) and Cu-ZIF/NF (31.39 mV dec−1). Combined XPS and EDS analyses unveiled a synergistic electronic structure modulation between Zn and Cu, which facilitated charge transfer and enhanced catalytic efficiency. A gas chromatography product analysis identified H2 and N2 as the primary gaseous products, confirming the predominant occurrence of the ammonia oxidation reaction (AOR). This study not only presents a noble metal-free electrocatalyst with exceptional efficiency and durability for ammonia decomposition but also demonstrates the significant potential of MOF-derived materials in sustainable hydrogen production technologies. Full article
(This article belongs to the Special Issue Advanced Energy Conversion Technologies Based on Energy Physics)
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20 pages, 5939 KiB  
Article
Mechanistic Insights into the Hot-Spot Formation and Pyrolysis of LLM-105 with Different Void Defects: A ReaxFF Molecular Dynamics Study
by Mengyun Mei, Zijian Sun, Lixin Ye and Weihua Zhu
Molecules 2025, 30(14), 3016; https://doi.org/10.3390/molecules30143016 - 18 Jul 2025
Viewed by 304
Abstract
To investigate the influences of void defects of different sizes, molecular dynamics combined with ReaxFF-lg reactive force field was used to study the hot-spot formation mechanism and thermal decomposition behavior of 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) crystals with different void defects at 2500 K. The results [...] Read more.
To investigate the influences of void defects of different sizes, molecular dynamics combined with ReaxFF-lg reactive force field was used to study the hot-spot formation mechanism and thermal decomposition behavior of 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) crystals with different void defects at 2500 K. The results indicate that larger void defects are more conducive to the formation of hot-spots. The consistency of the trends in time evolution of the potential energy, species numbers, and small molecules amounts between the ideal and void-containing LLM-105 crystals demonstrates that the presence of the void defect does not alter the decomposition mechanism of the LLM-105 molecule. An increase in the size of the void defect significantly increases the degree of diffusion of the C, H, O, and N atoms in the crystals, which affects the effective collisions between the atoms and thus alters the occurrence frequency of relevant reactions and the production of relevant products. Full article
(This article belongs to the Section Physical Chemistry)
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24 pages, 4002 KiB  
Article
CFD Simulation-Based Development of a Multi-Platform SCR Aftertreatment System for Heavy-Duty Compression Ignition Engines
by Łukasz Jan Kapusta, Bartosz Kaźmierski, Rohit Thokala, Łukasz Boruc, Jakub Bachanek, Rafał Rogóż, Łukasz Szabłowski, Krzysztof Badyda, Andrzej Teodorczyk and Sebastian Jarosiński
Energies 2025, 18(14), 3697; https://doi.org/10.3390/en18143697 - 13 Jul 2025
Viewed by 358
Abstract
Combustion processes in compression ignition engines lead to the inevitable generation of nitrogen oxides, which cannot be limited to the currently desired levels just by optimising the in-cylinder processes. Therefore, simulation-based engine development needs to include all engine-related aspects which contribute to tailpipe [...] Read more.
Combustion processes in compression ignition engines lead to the inevitable generation of nitrogen oxides, which cannot be limited to the currently desired levels just by optimising the in-cylinder processes. Therefore, simulation-based engine development needs to include all engine-related aspects which contribute to tailpipe emissions. Among them, the SCR (selective catalytic reduction) aftertreatment-related processes, such as urea–water solution injection, urea decomposition, mixing, NOx catalytic reduction, and deposits’ formation, are the most challenging, and require as much attention as the processes taking place inside the cylinder. Over the last decade, the urea-SCR aftertreatment systems have evolved from underfloor designs to close-coupled (to the engine) architecture, characterised by the short mixing length. Therefore, they need to be tailor-made for each application. This study presents the CFD-based development of a multi-platform SCR system with a short mixing length for mobile non-road applications, compliant with Stage V NRE-v/c-5 emission standard. It combines multiphase dispersed flow, including wall wetting and urea decomposition kinetic reaction modelling to account for the critical aspects of the SCR system operation. The baseline system’s design was characterised by the severe deposit formation near the mixer’s outlet, which was attributed to the intensive cooling in the mounting area. Moreover, as the simulations suggested, the spray was not appropriately mixed with the surrounding gas in its primary zone. The proposed measures to reduce the wall film formation needed to account for the multi-platform application (ranging from 56 to 130 kW) and large-scale production capability. The performed simulations led to the system design, providing excellent UWS–exhaust gas mixing without a solid deposit formation. The developed system was designed to be manufactured and implemented in large-scale series production. Full article
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14 pages, 3435 KiB  
Article
Thermal Risk Evaluation of the Fluorobenzotriazolone Nitration Process
by Yingxia Sheng, Qianjin Xiao, Hui Hu, Tianya Zhang and Guofeng Guan
Molecules 2025, 30(14), 2939; https://doi.org/10.3390/molecules30142939 - 11 Jul 2025
Viewed by 236
Abstract
This paper introduces the nitration process of obtaining the synthetic intermediate 1-(2-chloro-4-fluoro-5-nitrobenzene)-4-difluoromethyl-4,5-dihydro-3-methyl-1,2,4-triazol-5(1H)-one of pyraclostrobin using raw materials fluorobenzotriazolone, fuming nitric acid, fuming sulfuric acid, and toluene. The exothermic characteristics of the nitration, quenching, extraction, and alkali washing in the nitration reaction [...] Read more.
This paper introduces the nitration process of obtaining the synthetic intermediate 1-(2-chloro-4-fluoro-5-nitrobenzene)-4-difluoromethyl-4,5-dihydro-3-methyl-1,2,4-triazol-5(1H)-one of pyraclostrobin using raw materials fluorobenzotriazolone, fuming nitric acid, fuming sulfuric acid, and toluene. The exothermic characteristics of the nitration, quenching, extraction, and alkali washing in the nitration reaction were studied, and the thermal decomposition risk of the raw materials and the secondary decomposition risk of the products in the nitration process were evaluated. The results showed that the thermal decomposition risk of the four raw materials was level 1. The acceptable level of runaway reaction in the nitration process was evaluated to be level 2, the acceptable level of runaway reaction in the quenching was level 3, the acceptable level of runaway reaction in the extraction and the alkali washing was level 1, the process hazard level of the nitration reaction and the quenching was evaluated to be level 5, and the process hazard level of the extraction and the alkali washing was level 1. Based on the comprehensive assessment results, targeted risk mitigation and control strategies are proposed to ensure process safety. Full article
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20 pages, 6146 KiB  
Article
Adsorption and Decomposition Mechanisms of Li2S on 2D Thgraphene Modulated by Doping and External Electrical Field
by Ruofeng Zhang, Jiyuan Guo, Lanqing Chen and Fengjie Tao
Materials 2025, 18(14), 3269; https://doi.org/10.3390/ma18143269 - 10 Jul 2025
Viewed by 397
Abstract
The modification of materials is considered as one of the productive methods to facilitate the better electrochemical behavior of lithium–sulfur battery cathodes and inhibit the shuttle effect. Adopting first-principles calculations in this work, the application potential of pristine and B-, N-, and P-doped [...] Read more.
The modification of materials is considered as one of the productive methods to facilitate the better electrochemical behavior of lithium–sulfur battery cathodes and inhibit the shuttle effect. Adopting first-principles calculations in this work, the application potential of pristine and B-, N-, and P-doped thgraphene as anchoring materials was investigated. The results reveal that pristine and doped substrates have an excellent structural stability, conductivity, and electrochemical activity. In the absence of an electric field, four substrates exhibit a strong anchoring effect on the Li2S cluster, where the adsorption energies fall within 3.10 to 4.48 eV. Even under the external electric field, all substrates exhibit notable structural stability during Li2S adsorption processes and maintain a high electrical conductivity, with adsorption energies exceeding 2.75 eV. Furthermore, it has been observed that the interfacial diffusion energy barriers for Li on all substrates are below 0.35 eV, which effectively enhances Li migration and facilitates reaction kinetics. Additionally, Li2S demonstrates a low decomposition energy barrier (varying from 0.84 to 1.55 eV) on pristine and doped substrates, enabling the efficient regeneration of the active material during the battery cycling. These findings offer a scientific guideline for the design of pristine and doped thgraphene as an excellent anchoring material for advanced lithium–sulfur batteries. Full article
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13 pages, 3158 KiB  
Article
Process Safety Assessment of the Entire Nitration Process of Benzotriazole Ketone
by Yingxia Sheng, Qianjin Xiao, Hui Hu, Tianya Zhang and Guofeng Guan
Processes 2025, 13(7), 2201; https://doi.org/10.3390/pr13072201 - 9 Jul 2025
Viewed by 408
Abstract
To ensure the inherent safety of fine chemical nitration processes, the nitration reaction of benzotriazole ketone was selected as the research object. The thermal decomposition and reaction characteristics of the nitration system were studied using a combination of differential scanning calorimetry (DSC), reaction [...] Read more.
To ensure the inherent safety of fine chemical nitration processes, the nitration reaction of benzotriazole ketone was selected as the research object. The thermal decomposition and reaction characteristics of the nitration system were studied using a combination of differential scanning calorimetry (DSC), reaction calorimetry (RC1), and accelerating rate calorimetry (ARC). The results showed that the nitration product released 455.77 kJ/kg of heat upon decomposition, significantly higher than the 306.86 kJ/kg of the original material, indicating increased thermal risk. Through process hazard analysis based on GB/T 42300-2022, key parameters such as the temperature at which the time to maximum rate is 24 h under adiabatic conditions (TD24), maximum temperature of the synthesis reaction (MTSR), and maximum temperature for technical reason (MTT) were determined, and the reaction was classified as hazard level 5, suggesting a high risk of runaway and secondary explosion. Process intensification strategies were then proposed and verified by dynamic calorimetry: the adiabatic temperature increase (ΔTad) was reduced from 86.70 °C in the semi-batch reactor to 19.95 °C in the optimized continuous process, effectively improving thermal safety. These findings provide a reliable reference for the quantitative risk evaluation and safe design of nitration processes in fine chemical manufacturing. Full article
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12 pages, 3319 KiB  
Article
Research on the Thermal Decomposition Characteristics of PE Outer Sheath of High-Voltage Cables Under Different Humidity Levels
by Zhaoguo Wu, Qian Wang, Huixian Huang, Yong Li, Yulai Kuang, Hong Xiang, Junwei Liu and Zhengqin Cao
Energies 2025, 18(13), 3537; https://doi.org/10.3390/en18133537 - 4 Jul 2025
Viewed by 286
Abstract
Gas sensors can provide early warning of fires by detecting pyrolysis gas components in the sheaths of high-voltage cables. However, air humidity significantly affects the thermal decomposition gas production characteristics of the outer sheath of high-voltage cables, which in turn affects the accuracy [...] Read more.
Gas sensors can provide early warning of fires by detecting pyrolysis gas components in the sheaths of high-voltage cables. However, air humidity significantly affects the thermal decomposition gas production characteristics of the outer sheath of high-voltage cables, which in turn affects the accuracy of this warning method. In this paper, the thermal decomposition and gas production characteristics of the polyethylene (PE) outer jacket of high-voltage cables under different air humidities (20–100%) are studied, and the corresponding density functional theory (DFT) simulation calculations are performed using Gaussian 09W software. The results show that with the increase in humidity, the thermal decomposition gas yield of the PE outer jacket of high-voltage cables exhibits a decreasing trend. Under high-humidity conditions (≥68.28%RH), the generation of certain thermal decomposition gases is significantly reduced or even ceases. Meanwhile, the influence of moisture on the thermal decomposition characteristics of PE was analyzed at the micro level through simulation, indicating that the H-free radicals generated by moisture promote the initial decomposition of PE, but the subsequent combination of hydroxyl groups with terminal chain C forms a relatively stable alkoxy structure, increasing the activation energy of the reaction (by up to 44.7 kJ/mol) and thus inhibiting the generation of small-molecule gases. An experimental foundation is laid for the final construction of a fire warning method for high-voltage cables based on the information of thermal decomposition gas of the outer sheath. Full article
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14 pages, 1961 KiB  
Article
Characteristic Differences of Thermal Runaway Triggered by Overheating and Overcharging in Lithium-Ion Batteries and Multi-Dimensional Safety Protection Strategies
by Yao Yao, Lu Liu, Juan Gu, Haozhe Xing, Huachao Liu, Yihao Cheng, Youning Wang, Songlin Yue, Yanyu Qiu and Zhi Zhang
Batteries 2025, 11(7), 242; https://doi.org/10.3390/batteries11070242 - 24 Jun 2025
Viewed by 984
Abstract
Overheating and overcharging are the core triggering conditions for the thermal runaway of lithium-ion batteries. Studying the behavioral differences of thermal runaway of lithium-ion batteries under these two conditions is crucial for the safety design and protection of lithium-ion batteries. In this study, [...] Read more.
Overheating and overcharging are the core triggering conditions for the thermal runaway of lithium-ion batteries. Studying the behavioral differences of thermal runaway of lithium-ion batteries under these two conditions is crucial for the safety design and protection of lithium-ion batteries. In this study, we investigated the temperature, pressure, gas generation, and heat generation characteristics of lithium batteries under these two conditions. Under overheating conditions, the release of lattice oxygen in the cathode and the decomposition of the electrolyte trigger a self-catalytic reaction, generating CO2 (54.7%) and H2 (29.7%), with a total heat release of 17.6 kJ and a heat accumulation rate of 24.3 W, forming a local high-temperature core area. Under overcharging conditions, the voltage drop, capacity attenuation of 21.1% (2230→1762 mAh), and internal resistance surge (6→21 mΩ) reflect severe damage to the electrode. Accompanied by the oxygenation of the EC electrolyte (CO32− + C2H4↑), the gas production rate is faster. The middle pressure was 0.601 MPa, and the proportion of CO2 was 67.4%. However, the triggering of thermal runaway relies on the synergistic effect of internal electrochemical reactions and ohmic heat accumulation, resulting in a relatively low rate of energy accumulation. Full article
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25 pages, 8234 KiB  
Article
Preparation of Cu-Containing Substances via an Ultrasonic-Assisted Solvothermal Approach and Their Catalytic Effects on the Thermal Decomposition of Ammonium Perchlorate
by Cheng-Hsiung Peng, Pin-Hsien Su, Jin-Shuh Li and Yan-Jun Ke
Materials 2025, 18(13), 2928; https://doi.org/10.3390/ma18132928 - 20 Jun 2025
Viewed by 316
Abstract
In this study, a one-pot, ultrasonic-assisted solvothermal method was successfully employed to prepare three copper-containing compounds: copper benzene-1,3,5-tricarboxylate (Cu3(BTC)2), copper powder, and copper-metalized activated carbon (Cu@AC). This method is efficient and safe and has potential for use in scalable [...] Read more.
In this study, a one-pot, ultrasonic-assisted solvothermal method was successfully employed to prepare three copper-containing compounds: copper benzene-1,3,5-tricarboxylate (Cu3(BTC)2), copper powder, and copper-metalized activated carbon (Cu@AC). This method is efficient and safe and has potential for use in scalable production. The characteristics of the resulting products were analyzed using various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), specific surface area measurement along with pore size distribution, and thermogravimetric analysis–differential scanning calorimetry (TG-DSC). Additionally, the catalytic effects of these products on the thermal decomposition of ammonium perchlorate (AP) were evaluated. All three substances were found to lower the thermal decomposition temperature of AP and enhance heat release. Cu3(BTC)2 demonstrated exceptional catalytic performance and compatibility with AP, as shown using the vacuum stability test (VST). The thermal analysis results indicated that the thermal decomposition temperature and apparent activation energy of AP decreased from ~442 °C to around 340 °C and from ~207 kJ mol−1 to approximately 128 kJ mol−1, respectively, when 3 wt% Cu3(BTC)2 was contained in AP. Moreover, the heat released via the exothermic decomposition of AP increased from 740 J g−1 to1716 J g−1. A possible reaction mechanism is proposed based on the evolved gas analysis (EGA) findings to explain the observed catalytic effects. Full article
(This article belongs to the Section Catalytic Materials)
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16 pages, 1496 KiB  
Article
Annealing of Oxygen-Related Frenkel Defects in Corundum Single Crystals Irradiated with Energetic Xenon Ions
by Kotomin A. Eugene, Ruslan Assylbayev, Guldar Baubekova, Irina Kudryavtseva, Vladimir N. Kuzovkov, Alise Podelinska, Viktor Seeman, Evgeni Shablonin and Aleksandr Lushchik
Crystals 2025, 15(6), 573; https://doi.org/10.3390/cryst15060573 - 18 Jun 2025
Viewed by 307
Abstract
The recovery of radiation damage induced by 231-MeV xenon ions with varying fluence (from 5 × 1011 to 2 × 1014 cm−2) in α-Al2O3 (corundum) single crystals has been studied by means of isochronal thermal annealing [...] Read more.
The recovery of radiation damage induced by 231-MeV xenon ions with varying fluence (from 5 × 1011 to 2 × 1014 cm−2) in α-Al2O3 (corundum) single crystals has been studied by means of isochronal thermal annealing of radiation-induced optical absorption (RIOA). The integral of elementary Gaussians (product of RIOA spectrum decomposition) OK has been considered as a concentration measure of relevant oxygen-related Frenkel defects (neutral and charged interstitial-vacancy pairs, F-H, F+-H). The annealing kinetics of these four ion-induced point lattice defects has been modelled in terms of diffusion-controlled bimolecular recombination reactions and compared with those carried out earlier for the case of corundum irradiation by fast neutrons. The changes in the parameters of interstitial (mobile component in the recombination process) annealing kinetics—activation energy E and pre-exponential factor X—in ion-irradiated crystals are considered. Full article
(This article belongs to the Section Materials for Energy Applications)
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