THERMOCHIMICA ACTA
·
2015
·
IF 2.184
Kai Wang,Dabin Liu,Sen Xu,Gaowen Cai
2-Ethylhexyl nitrate (EHN) and nitrocellulose (NC) are commonly used energetic materials that have caused many thermal runaway reactions and explosions worldwide, and their thermal stabilities have always been an important issue. Based on the results of Roduit et al. (2013), differential scanning calorimetry (DSC) was used in this study to investigate the thermal history’s influence on the thermal stabilities of EHN and NC at different heating rates. The decomposition kinetics of EHN and NC were determined by the Friedman isoconversional method. The kinetic parameters with heat balance were analysed and used for the simulation of the adiabatic behavior time to the maximum rate under adiabatic conditions (TMR ad ). The results indicated that the thermal history significantly influenced the dynamic DSC curves, decomposition kinetics and thermal stability of NC, which decomposes autocatalytically. The influence was negligible on EHN, whose decomposition proceeds according to the “ n th order” law.
研究领域:
化学
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材料科学
·
安全工程
✓ 已验证
DOI
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 39
·22198-22204
·
IF 3.049
Fang Yang,Ya Chen,Chuande Zhao,Long Zhang
Thermal decomposition of a highly thermostable explosive dihydroxylammonium 2,4,8,10-tetranitro-benzopyrido-1,3a,6,6a-tetraazapentalene (BPTAP) was studied using conventional thermal analysis techniques (Thermal Gravimetric Analysis and Differential Scanning Calorimetry). To obtain more comprehensive insight into the kinetics mechanism of BPTAP decomposition, thermoanalytical experiments were performed under non-hermetic and hermetic conditions. Several widely used thermoanalytical data processing techniques based on model-free kinetics (Flynn–Wall–Ozawa, Kissinger, Freidman, numerical optimization) were studied and compared. Furthermore, to fully understand the thermal safety property of BPTAP, the kinetic model and the kinetic parameters were evaluated based on the non-isothermal DSC data by using a non-linear optimization method. The kinetic models of thermal decomposition of BPTAP under non-hermetic and hermetic conditions were different, which were identified as the generalized autocatalysis reaction and two parallel generalized autocatalysis reactions, respectively. On the basis of the aforementioned study, two important safety parameters including the time to maximum rate under adiabatic conditions and self-accelerating decomposition temperature for BPTAP in DEWAR were calculated and discussed.
研究领域:
化学
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材料科学
·
爆炸物研究
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DOI
PubMed
高影响因子
Materials
·
2020
·Vol. 13
·期 20
·4478
·
IF 3.057
Qiangqiang Liu,Yubo Chai,Lin Ni,Wenhua Lyu
This paper presents experimental research on the flame-retardant properties and thermal decomposition kinetics of wood treated by boric-acid-modified silica sol. The poplar wood was impregnated with pure silica sol and boric-acid-modified silica sol. The results showed that modifiers can be observed in the cell wall and cell lumen. The ignition time, second peak of the heat release rate, total heat release, and mass loss of the W-Si/B were delayed obviously. The composite silicon modification had a positive impact on carbonization. Thermogravimetric analysis showed that the residual mass of W-Si/B was enhanced and the thermal degradation rate was considerably decreased. By thermal decomposition kinetics analysis, the boric acid can catalyze the thermal degradation and carbonization of poplar wood. In other words, wood treated with boric-acid-modified silica sol showed significant improvement in terms of flame retardancy, compared with wood treated with common silica sol.Keywords:poplar wood;silica sol;boric acid;cone calorimetric;decomposition kinetics
研究领域:
材料科学
·
林业工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Huang Liu,Huashi Li,Desong Yao,Ping Guo,Lianhui Wen
Due to the weak cementation of natural gas hydrate (NGH) reservoir in the seabed, during both the drilling and development processes, a multiphase (gas hydrate-sediments-seawater-natural gas mixture) flow is more likely to exist in the NGH reservoir and development wells, understand the natural gas hydrate particle dissociation kinetic in the hydrate-sediments/seawater slurries is important. In this work, first, a new NGH phase behavior research experimental apparatus contains a strong magnetic stirrer was built. By using this, we for the first time proposed to form NGH reservoir in the water saturated sands under stirring in the laboratory, which showed a much higher hydrate formation rate and water to hydrate conversation ratio than the usual static formation method. After that, the CH 4 hydrate-sands/seawater slurries were produced, the influence of pressures, temperatures, the size of sands, and stirring rates on CH 4 hydrate dissociation kinetic in the slurry were investigated. The dissociation rate of CH 4 hydrate-sands mixed particles markedly increased with decreasing operation pressure from 3 MPa to 0.1 MPa. The average dissociate rate reached 1762.57 mL/min at 0.1 MPa. It is interesting that unlike to the single NGH reservoir, no hydrate secondary formation and ice formation phenomenon arose in the hydrate-sands/seawater slurries during the CH 4 hydrate dissociation process. The increase of temperature and stirring rate substantially stimulated the dissociation of CH 4 hydrate particles in the slurry, while the sands’ size showed little effect. In addition, a high precision kinetic model for describing the dissociation of CH 4 hydrate in hydrate-sands/seawater slurries was built, in which the influence of pressure, temperature and stirring rate on the hydrate apparent dissociation rate constant was considered at the same time.
研究领域:
化学工程
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Jingkun Wang,Jidong Sun,Yuliang Liu,Xun Zhang,Kai Cheng,Yupeng Chen,Fangzhou Zhou,Jujie Luo,Tianbao Li,Junjie Guo,Bingshe Xu
Modification of oxygen evolution co-catalyst (OEC) on the surface of bismuth vanadate (BiVO 4 ) can effectively improve the kinetics of water oxidation, but it is still limited by the small hole extraction driving force at the BiVO 4 /OEC interface. Modulating the BiVO 4 /OEC interface with a hole transfer layer (HTL) is expected to facilitate hole transport from BiVO 4 to the OEC surface. Herein, a copper(I) thiocyanate (CuSCN) HTL is inserted between BiVO 4 and NiFeO x OEC to create BiVO 4 /CuSCN/NiFeO x photoanode, resulting in a significant enhancement of photoelectrochemical (PEC) water splitting performance. From electrochemical analyses and density functional theory (DFT) simulations, the markedly enhanced PEC performance is attributed to the insertion of CuSCN as an HTL, which promotes the extraction of holes from BiVO 4 surface and boosts the water oxidation kinetics. The optimal photoanode achieves a photocurrent density of 5.6 mA cm −2 at 1.23 V versus the reversible hydrogen electrode (vs. RHE) and an impressive charge separation efficiency of 96.2 %. This work offers valuable insights into the development of advanced photoanodes for solar energy conversion and emphasizes the importance of selecting an appropriate HTL to mitigate recombination at the BiVO 4 /OEC interface.
研究领域:
材料科学
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能源转换
·
界面工程
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产品关联
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2019
·
IF 8.456
Chenglong Wang,Xuefeng Long,Shenqi Wei,Tong Wang,Feng Li,Lili Gao,Yiping Hu,Shuwen Li,Jun Jin
Earth-abundant hematite is an attractive photoanode for photoelectrochemical water splitting, whereas the intrinsic properties of inferior charge transfer and slow water oxidation kinetics still hinder its application. In response, an integrated photoanode has been constructed with hematite nanorod arrays modified by fluorine anion doping and further decorated with amorphous CoAl-layered double hydroxides (CoAl-LDH). This novel CoAl-LDH/F–Fe2O3 photoanode exhibited an excellent photocurrent density of 2.46 mA cm–2 at 1.23 V versus reversible hydrogen electrode (VRHE), five times enhanced than that of pristine α-Fe2O3. Systematic investigations reveal that fluorine anion serving as a donor dopant dramatically enhances the density of charge carrier and reduces the resistance of hematite for rapid charge transfer. Furthermore, the cocatalyst of CoAl-LDH could effectively passivate the surface defects of F–Fe2O3 and facilitate the water oxidation kinetics through an alternative pathway of holes trapped by Co species. As a consequence, the charge separation efficiencies of the bulk and surface were improved to 32.6 and 81.8%, respectively, compared with those of α-Fe2O3 (9.7 and 31.7%). Our results demonstrate that the dual modification of the bulk and surface is an attractive maneuver to ameliorate the water oxidation activity of hematite.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SOLAR ENERGY MATERIALS AND SOLAR CELLS
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2022
·
IF 7.305
Yun Da,Jialei Zhou
The ability of calcium-based composites to simultaneously improve optical absorption and accelerate decomposition kinetics represents a major endeavor direction in the direct solar-driven thermochemical energy storage system. Doping strategy has been macroscopically proved to be an effective way in boosting optical absorption properties and calcination kinetics, but the underlying microscopic mechanisms are still unclear. This paper aims to reveal the mechanisms of optical absorption enhancement and accelerated decomposition kinetics for Mn-doped CaCO 3 through both experiments and density function theory (DFT). In the experiment, the optical absorption of Mn-doped CaCO 3 was much higher than that of pure CaCO 3 . The sample CaCO 3 –7Mn displayed satisfied optical absorption and fabulous cycling stability. The optical absorption reached 74% and energy storage density only decreased 2.6% after 20 cycles. Meanwhile, the decomposition reaction rate equations of pure CaCO 3 and Mn-doped CaCO 3 were obtained via non-isothermal kinetic analysis . The results indicated that doping Mn could accelerate decomposition kinetics of CaCO 3 by reducing the apparent activation energy . In the DFT calculation, the complex refractive index of Mn-doped CaCO 3 was lower in real part (refractive index) and higher in imaginary part (extinction coefficient) within the wavelength range from 300 to 2500 nm compared with pure CaCO 3 , which was closely related to the electron cloud distribution in the calcite crystal structure. Moreover, Mn-doped CaCO 3 has lower transition state energy barrier and dissociation energy than pure CaCO 3 . The calculation results revealed the mechanisms of doping Mn in CaCO 3 to enhance the light absorption and accelerate the decomposition kinetics from the microscopic perspective at atomic level. This work contributes to understanding the physical mechanisms of doping elements on boosting the performance of calcium-based composites at the molecular level.
研究领域:
材料科学
·
能源存储
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED ENERGY
·
2023
·
IF 11.2
X.C. Han,H.J. Xu,W.S. Hua
MgO/Mg(OH) 2 is a potential thermochemical material with high heat density and stable characteristics. Four additives including Carbons, Carbides, Nitrides and Titanates were selected for modification. The decomposition behavior and kinetics analysis were both investigated. It is found that Titanates has a catalytic effect, and the tested energy storage density can be increased to 971 J/g. The spectral absorption of candidate material with 6% graphite can reach to more than 50% and 6% CaTiO 3 has an extremely high absorption in the short wave segment. In microscopic morphology, Mg(OH) 2 particles sintered at high temperature will form adhesion agglomeration. Due to the special microstructures of candidate materials, agglomeration phenomenon is effectively alleviated and the candidate materials with 6% graphite or CaTiO 3 are both ideal modified materials. The optimized mechanism of modified material with 6% CaTiO 3 was illustrated by model. To investigate the kinetics mechanism, the model of non-isothermal decomposition was developed. The activation energies of pure material, sample with 6%graphite and sample with 6%CaTiO 3 are 141 kJ/kg, 113 kJ/kg and 122 kJ/kg respectively. The shape factor polynomials and kinetic governing equations were obtained. According to the established kinetics equations, the heating processes at 8 K, 12 K and 25 K/min were predicted. The study can provide a necessary kinetics reference for the numerical calculation of thermochemical heat storage.
研究领域:
材料科学
·
热能工程
✓ 已验证
产品关联
DOI
高影响因子
Advanced Powder Materials
·
2024
·
IF 28.6
Hongqiang Zhang,Tiansheng Bai,Jun Cheng,Fengjun Ji,Zhen Zeng,Yuanyuan Li,Chenwu Zhang,Jiaxian Wang,Weihao Xia,Naixuan Ci,Yixuan Guo,Dandan Gao,Wei Zhai,Jingyu Lu,Lijie Ci,Deping Li
The development of high-energy-density Li-ion batteries is hindered by the irreversible capacity loss during the initial charge-discharge process. Therefore, pre-lithiation technology has emerged in the past few decades as a powerful method to supplement the undesired lithium loss, thereby maximizing the energy utilization of LIBs and extending their cycle life. Lithium oxalate (Li 2 C 2 O 4 ), with a high lithium content and excellent air stability, has been considered one of the most promising materials for lithium compensation. However, the sluggish electrochemical decomposition kinetics of the material severely hinders its further commercial application. Here, we introduce a recrystallization strategy combined with atomic Ni catalysts to modulate the mass transport and decomposition reaction kinetics. The decomposition potential of Li 2 C 2 O 4 is significantly decreased from ∼4.90V to ∼4.30V with a high compatibility with the current battery systems. In compared to the bare NCM//Li cell, the Ni/N-rGO and Li 2 C 2 O 4 composite (Ni-LCO) modified cell releases an extra capacity of ∼11.7 %. Moreover, this ratio can be magnified in the NCM//SiO x full cell, resulting in a 30.4 % higher reversible capacity. Overall, this work brings the catalytic paradigm into the pre-lithiation technology, which opens another window for the development of high-energy-density battery systems.
研究领域:
材料科学
·
能源存储与转换
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2025
·
IF 7.5
Miaomiao Feng,Xing Wei,Qingqiang Wang,Xunli Zhang,Nan Jin,Ying Chen,Quan Li,Yuchao Zhao
The conversion of biomass glucose to formic acid (FA) has been demonstrated as a promising sustainable manufacturing process, further enhanced by the application of the microchannel reactor technology. However, FA decomposition remains a challenge, limiting FA yield in the catalytic oxidation process. To gain insights into the reaction kinetics of FA decomposition, the effects of reaction temperature, O 2 pressure, residence time, catalyst content (H 5 PV 2 Mo 10 O 40 ), and pH value on FA decomposition were systematically investigated. The results showed that FA decomposition involved hydrothermal decomposition, acid decomposition, and catalytic oxidative decomposition. When the reaction temperature exceeded 160 °C, the degree of FA decomposition increased significantly. High oxygen partial pressure, long residence time, and high catalyst content all had a significant positive impact on the FA decomposition. The decomposition of FA in this process was found to follow second-order kinetics, with an apparent activation energy of 154.1 kJ/mol. Based on these findings, a novel strategy was proposed and evaluated by coupling reaction and extraction processes facilitated by a gas–liquid-liquid three-phase flow configuration in a microchannel reactor, enabling the in-situ extraction of FA from the strong oxidative environment using isoamyl alcohol. By minimizing the oxidative decomposition of FA during FA production, this development provides an effective means to enhance the process efficiency of biomass-to-FA production.
研究领域:
化学工程
·
可再生资源技术
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2015
·Vol. 122
·期 1
·349-358
·
IF 2.042
Yu Guo-Min,Wang Li-Sheng,Sun Jian,Shao Xian-Zhao
A phosphorous flame retardant of phosphoric acid, P, P′-1, 4-phenylene P, P, P′, P′-tetraphenyl ester (PAPTE) was synthesized by diphenyl chlorophosphate and hydroquinone. The structural features of PAPTE were investigated with mass spectrometry, infrared spectroscopy, X-ray powder diffraction and nuclear magnetic resonance methods. The thermal behavior of PAPTE was carried out with thermogravimetric (TG) analysis instruments. The kinetic parameters, including the activation energy and pre-exponential factor of the decomposition process for the title compound, were calculated through the Friedman method, the Kissinger–Akahira–Sunose method and the Flynn–Wall–Ozawa method, while the thermal decomposition mechanism was also studied with the invariant kinetic parameters (IKP) method based on a set of TG data obtained at different heating rates. It was shown that the activation energies calculated for the decomposition reaction by different methods were found to be consistent with the conversion functions calculated by means of the IKP method which depend on a set of kinetic methods.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Yurong Gu,Tongzhou Liu,Qian Zhang,Wenyi Dong
As one of the most reactive species, hydrated electron (e aq − ) is promising for decomposing recalcitrant organic pollutants, such as perfluorooctanoic acid (PFOA). In this study, PFOA decomposition was systematically investigated using a high photon flux ultraviolet (UV)/sulfite system. It showed had fast PFOA decomposition kinetics through significant promotion of e aq − production at favorable pH condition (pH > 9.2). At initial solution pH 9.2, with initial dissolved oxygen (DO) about 5 mg/L, and at around 25 °C, all PFOA was decomposed to less fluorinated compounds within 10 min from its initial concentration of 38.7 μM. Accompanying PFOA decomposition, short chain perfluorocarboxylic acids (PFCAs) and less fluorinated compounds were detected, indicating a stepwise decomposition mechanism. The k obs of PFOA decomposition was 0.455 min −1 , and approximately 6–910 folds faster than those reported by other reductive methods. At a fixed UV photon flux, PFOA decomposition kinetics showed a positive linear dependence with the initial sulfite dosage. Increasing initial sulfite dosage at a less favorable pH condition (pH 8.0) showed enhancement in PFOA decomposition. But it does not work at acidic and neutral pH conditions. The residual sulfite in the treated solution has acute toxicity, but it can be efficiently removed by using aeration. The outcomes of study will extend the understanding of the high photon flux UV/sulfite treatment system, and help to facilitate its further practical use in recalcitrant organic pollutants decomposition.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）