MOLECULES
·
2024
·Vol. 29
·期 23
·5668
·
IF 4.2
Dengxun Ren,Zexu Fan,Jiaqu Zhang,Yi Xu,Xianzhong Tang,Mingzhen Xu
To study the properties of cyclotriphosphazene (CTP)-containing phthalonitriles, a branched phthalonitrile containing CTP (CTP–PN) with self-catalytic behavior was designed and synthesized. The structure of CTP–PN was characterized by FT–IR (Fourier transform infrared spectroscopy), MS (mass spectroscopy), 1 H–NMR (proton nuclear magnetic resonance spectroscopy), and 13 C–NMR (carbon nuclear magnetic resonance spectroscopy). Then, the curing reaction of CTP–PN was studied using DSC (differential scanning calorimetry) and DRA (dynamic rheological analysis). The results show that the curing reaction of CTP–PN is initiated at 200 °C. Additionally, the change in the viscosity of CTP–PN as a function of the temperature was investigated. After curing at different temperatures, the generated structures were characterized by FT–IR. The fracture morphology and thermomechanical properties of cured CTP–PN were scanned and studied using SEM (scanning electron microscopy) and TMA (thermomechanical analysis), respectively. The results demonstrate that CTP–PN exhibits a smooth fracture surface and possesses a relatively low CTE (coefficient of linear thermal expansion) of approximately 25 ppm/°C at 285 °C. A T d5% (temperature at which 5% weight loss occurs) of as high as 405 °C can be obtained for cured CTP–PN, and its char yield at 800 °C exceeds 70% in N 2 . FT–IR and XPS (X-ray photoelectron spectroscopy) were used to study the thermal decomposition of cured CTP–PN, indicating that it remains stable below 350 °C. With an increasing temperature, there is decomposition first of CTP and P–NH–Ph and C–O–C bonds (>350 °C) and then nitrogen-containing aromatic heterocycles (>500 °C), ultimately resulting in the formation of P-containing residual char.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2019
·Vol. 141
·期 4
·1413-1423
·
IF 2.471
Zhang Ming,Zhao Fengqi,Yang Yanjing,Li Hui,Gao Hongxu,Yao Ergang,Zhang Jiankan,An Ting,Jiang Zhoufeng
Bimetallic iron oxides (NiFe 2 O 4 , ZnFe 2 O 4 and CoFe 2 O 4 ) were prepared via the facile solvothermal method and characterized using SEM, TEM, XRD, FTIR, XPS and BET instruments. The catalytic behavior of the bimetallic iron oxides on the thermal decomposition of 5, 5′-bistetrazole-1, 1′-diolate (TKX-50) was studied using DSC and TG-DTG methods. Besides, the corresponding kinetic parameters of TKX-50 thermal decomposition were calculated by multi-kinetics methods including traditional, iso-conversional and iteration methods. The thermal decomposition peak temperature ( T p ) and the activation energy ( E a ) reduced obviously after the addition of bimetallic iron oxides. Among different bimetallic iron oxides, the ZnFe 2 O 4 has the best catalytic activity for TKX-50 thermal decomposition. The high thermal decomposition peak temperature ( T HDP ) and average apparent activation energy ( E a ) of TKX-50 were decreased by 47.0 °C and 34.34 kJ mol −1 in the presence of ZnFe 2 O 4 sample. The excellent catalytic activity of ZnFe 2 O 4 for thermal decomposition of TKX-50 makes it a promising combustion catalyst of insensitive solid propellants containing TKX-50.
研究领域:
材料科学
·
燃烧与推进
·
物理化学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2024
·
IF 20.2
Yihui Li,Ziang Zhao,Min Zhao,Hejun Zhu,Xinzheng Ma,Zheng Li,Wei Lu,Xingkun Chen,Linbin Ying,Ronghe Lin,Yu Meng,Yuan Lyu,Li Yan,Yunjie Ding
Promotional effects of oxygen vacancies of spinel catalysts in CO 2 hydrogenation are reported in early works, but the mechanistic origins remain elusive. Here, CoAl 2 O 4 spinels with varying numbers of oxygen vacancies are deliberately designed by a sol-gel method and different post-treatments. By combining catalytic testing, advanced electron microscopic and spectroscopic characterizations, and computational studies, the unusual oxygen vacancy-dependent catalytic behaviors are rationalized. Our work reveals that i) perfect spinel crystals possessing least oxygen vacancies can effectively constrain the Co 2+ species at working conditions that are less active but selective to CO; and ii) vacancy-rich spinels promote both H 2 and CO 2 activations and COOH* formation, explaining the higher hydrogenation activity, but overwhelming vacancies cause Co 2+ reduction and promote direct CO 2 * dissociation to CO* and deep hydrogenation to CH 4 . These molecular-level understandings reinforce the idea of proper design of oxygen vacancies to achieve activity-selectivity balance.
研究领域:
材料科学
·
催化化学
·
表面科学
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED MATERIALS
·
2021
·Vol. 33
·期 16
·2100229
·
IF 30.849
Yanxia Wang,Yangyang Lai,Jun Chu,Zichao Yan,Yun-Xiao Wang,Shu-Lei Chou,Hua-Kun Liu,Shi Xue Dou,Xinping Ai,Hanxi Yang,Yuliang Cao
Room-temperature (RT) sodium–sulfur (Na–S) batteries hold great promise for large-scale energy storage due to the advantages of high energy density, low cost, and resource abundance. The research progress on RT Na–S batteries, however, has been greatly hindered by the sluggish kinetics of the sulfur redox reactions. Herein, an elaborate multifunctional architecture, consisting of N-doped carbon skeletons and tunable MoS 2 sulfiphilic sites, is fabricated via a simple one-pot reaction followed by in situ sulfurization. Beyond the physical confinement and chemical binding of polarized N-doped carbonaceous microflowers, the MoS 2 active sites play a key role in catalyzing polysulfide redox reactions, especially the conversion from long-chain Na 2 S n (4 ≤ n ≤ 8) to short-chain Na 2 S 2 and Na 2 S. Significantly, the electrocatalytic activity of MoS 2 can be tunable via adjusting the discharge depth. It is remarkable that the sodiated MoS 2 exhibits much stronger binding energy and electrocatalytic behavior compared to MoS 2 sites, effectively enhancing the formation of the final Na 2 S product. Consequently, the S cathode achieves superior electrochemical performance in RT Na–S batteries, delivering a high capacity of 774.2 mAh g −1 after 800 cycles at 0.2 A g −1 , and an ultrahigh capacity retention with a capacity decay rate of only 0.0055% per cycle over 2800 cycles.
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
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Qiong Tang,Zhiping Zhao,Jun Han,Yuqi Shen,Leizhen Ge,Ting Li,Jinxiang Dong,Lei Liu
Lewis acidic ionic liquids as catalysts for alkylation reactions exhibited the potential for industrial application. Herein, the catalytic behavior of AlCl 3 -based ionic liquids with four organic ammonium salts was studied in the alkylation of naphthalene with n-octene for production of lubricating base oil, with special focus on the deactivation and recovery of ionic liquid. The Et 3 NHCl-AlCl 3 ionic liquid exhibited better catalytic performance than others due to its stronger interaction with naphthalene, as evidenced by the adsorption test of naphthalene over ionic liquids. To understand the deactivation mechanism, the deactivated catalysts were extensively characterized by FT-IR and UV–vis. The protonation effect of ionic liquids on polyalkylation products in the presence of HCl was found to aggravate the deactivation of ionic liquid. The negative effect is easily reversed by the decompression treatment on the reaction system before catalyst recovery, this method markedly enhanced the cycling durability of ionic liquids for industrial application.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Lijun Yang,Jiaxing Zhang,Mengfan Wang,Yutong Wang,Wei Qi,Zhimin He
As bridging species between short peptides and macromolecular proteins, peptide assemblies not only provide a supramolecular approach for the fabrication of controllable molecular machines with enzyme-like functions, but also a simplified model for understanding the catalytic mechanism of natural enzymes. In this study, we focused on probing the effect of microenvironment on the catalytic behavior of peptide assemblies. Upon simply replacing the X residue in Fmoc-FFXAH-CONH 2 , we realized the modulation of the microenvironment of the amyloid assemblies, which thus appeared esterase-like function with different catalytic abilities. The chemistry , structure and activity were analyzed to explore the principles that how the hydrophobic, charged, polar and chiral microenvironment deciding the catalytic behavior of the esterase mimic. In addition, we also presented the potential of the catalytic assemblies in the encapsulation, delivery and enzymatic metabolization of a mutual prodrug . This work sheds new insights for understanding the structure–function relationship of catalytic peptide assemblies and natural enzymes, and also provides a new avenue for the designing of artificial enzymes with better functions.
研究领域:
生物化学
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分子生物学
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催化科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INORGANIC CHEMISTRY
·
2023
·
IF 4.6
Hao Wang,Wenxin Bao,Muhammad Tariq Sarwar,Luyuan Tian,Aidong Tang,Huaming Yang
Local geometric configurations of metal cations in inorganic enzyme mimics determine their catalytic behaviors, while their optimization remains challenging. Herein, kaolinite, a naturally layered clay mineral, achieves the optimization of cationic geometric configuration in manganese ferrite. We demonstrate that the exfoliated kaolinite induces the formation of defective manganese ferrite and makes more iron cations fill into the octahedral sites, significantly enhancing the multiple enzyme-mimicking activities. The steady-state kinetic assay results show that the catalytic constant of composites toward 3,3′,5,5′-tetramethylbenzidine (TMB) and H2O2 are more than 7.4- and 5.7-fold higher than manganese ferrite, respectively. Furthermore, density functional theory (DFT) calculations reveal that the outstanding enzyme-mimicking activity of composites is attributed to the optimized iron cation geometry configuration, which has a higher affinity and activation ability toward H2O2 and lowers the energy barrier of key intermediate formation. As a proof of concept, the novel structure with multiple enzyme-mimicking activities amplifies the colorimetric signal, realizing the ultrasensitive visual detection of disease marker acid phosphatase (ACP), with a detection limit of 0.25 mU/mL. Our findings provide a novel strategy for the rational design of enzyme mimics and an in-depth investigation of their enzyme-mimicking properties.
研究领域:
生物化学
·
材料科学
·
医学诊断
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ORGANIC PROCESS RESEARCH & DEVELOPMENT
·
2022
·
IF 3.858
Wenshuai Bai,Dayu Zhang,Xingyu Wen
In the fine and pharmaceutical chemical industries, the operation of highly exothermic reactions with the autocatalytic feature needs great caution. Identification of the autocatalytic behavior for a given reaction is of signification importance. In this work, first, an autocatalytic mathematic model for the acetic anhydride hydrolysis reaction is established. Then, a series of experiments at an approximate mole ratio of acetic anhydride to water with the solvent of acetic acid are designed to study this reaction by reaction calorimetry. Third, the six isothermal experiments are used to fit the kinetic constants, and the fitting result is very good and reasonable when compared to the published literature. Besides, it is proven that this reaction also has an autocatalytic feature at an approximate mole ratio of acetic anhydride to water. Last, the determined kinetic constants are also verified by two experiments operating under isoperibolic conditions.
研究领域:
化学工程
·
精细化工
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Wenping Yang,Wenbin Gong,Longjiao Zhu,Xuan Ma,Wentao Xu
Although nanozymes have shown significant potential in wastewater treatment, enhancing their degradation performance remains challenging. Herein, a novel catalytic behavior was revealed for defective nanozymes with catalase-mimicking characteristics that efficiently degraded tetracycline (TC) in wastewater. Hydroxyl groups adsorbed on defect sites facilitated the in-situ formation of vacancies during catalysis, thereby replenishing active sites. Additionally, electron transfer considerably enhanced the catalytic reaction. Consequently, numerous reactive oxygen species (ROS) were generated through these processes and subsequent radical reactions. The defective nanozymes, with their unique catalytic behavior, proved effective for the catalytic degradation of TC. Experimental results demonstrate that • OH, • O 2 − , 1 O 2 and e − were the primary contributors to the degradation process. In real wastewater samples, the normalized degradation rate constant for defective nanozymes reached 26.0 min −1 g −1 L, exceeding those of other catalysts. This study reveals the new catalytic behavior of defective nanozymes and provides an effective advanced oxidation process for the degradation of organic pollutants.
研究领域:
环境科学
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生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2019
·Vol. 30
·期 10
·9363-9371
·
IF 2.195
Xue Xiangxin,Chen Lei,Zhao Cuimei,Wang Hairui,Nie Ping,Chang Limin
In this paper, the photocatalytic behavior of CdSe/CdS quantum dots (QDs) in reducing the graphene oxide (GO) with different surface ligands was investigated. Here, three surface ligands of different functional groups (oleic acid, poly (acrylic acid polymers) and S 2− ) were selected to study the influence of surface ligands on photocatalytic behavior of the CdSe/CdS QDs. Meanwhile, the obtained samples can be used as photocatalyst, and the photocatalytic activity was evaluated by photodegrading a methylene blue solution. It turned out that the QDs–S 2− –GO sample showed the highest photocatalytic activity under visible-light irradiation. Different surface ligand has different influence on the charge separation efficiency, which has different influence on photocatalytic behavior. The results show that the photocatalytic behavior is highly dependent on the electron attracting ability of the surface ligands on the CdSe/CdS QDs. Finally, a possible photocatalytic mechanism is proposed.
研究领域:
材料科学
·
光催化
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2017
·
IF 2.843
Lei Ni,Juncheng Jiang,M. Sam Mannan,Ahmed Mebarki,Mingguang Zhang,Xuhai Pan,Yong Pan
The present paper deals with thermal runaway risk of esterification reaction in semibatch reactor. It identifies thermal runaway conditions for the esterification of 2-butanol (2B) and propionic anhydride (PA) with sulfuric acid (SA). The autocatalytic kinetic model of esterification of 2B and PA with SA was obtained by the experiments. A new boundary diagram was proposed for the autocatalytic parallel reactions. Then, the combined boundary diagram considering the target temperature and maximum allowable temperature was used to define the critical conditions for the thermal runaway. The conditional probability of thermal runaway for esterification of 2B and PA with SA was calculated by Monte Carlo simulations.
研究领域:
化学工程
·
安全科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2022
·Vol. 97
·期 7
·1781-1791
·
IF 3.709
Yuying Ma,Haixia Zhao,Dongze Ma,Junmei Zhang
(Synthesis, characterization, and catalytic behaviour of nano-bimetallic nickel oxide on the thermal decomposition of dihydroxylammonium-5,5′-bistetrazole-1,1′-diolate) Bimetal combustion catalyst has become an emerging field in recent years, which is still in its infancy. When the combustion catalyst is used in double-base propellants, it can produce effects that conventional catalysts cannot achieve. In this study, nano-bimetallic nickel oxides (nanospheres of NiFe 2 O 4 and the sub-nanometre flower NiCo 2 O 4 ) were prepared by hydrothermal method and characterized using X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and N2 adsorption–desorption test (BET). Moreover, its thermal catalytic action on dihydroxylammonium 5,5'-bistetrazole-1,1'-diolate (TKX-50) was studied. The thermal analysis of composite TKX-50/NiFe 2 O 4 and TKX-50/NiCo 2 O 4 was carried out by thermogravimetric differential scanning calorimetry (TG-DSC). The results show that when the addition amount of NiFe2O4 is 10%, the heating rate is 5.0 K min −1 , the NiFe 2 O 4 has the best catalytic activity for TKX-50 thermal decomposition, and the high thermal decomposition peak temperature (Tpeak1) is decreased by 29 °C. More interestingly, the apparent activation energies of the two composites were calculated by Kissinger, Ozawa, and Starink methods. The advanced thermal analysis kinetics software (AKTS) was used to perform kinetic calculations on the DSC experimental curves of the above-mentioned composite energetic materials, and reaction rate curves obtained by the simulation are in good agreement with the experimental curves of the thermal decomposition reaction process, further proving that the accuracy of the experiment is high. Therefore, the addition of NiFe 2 O 4 shows high catalytic efficiency on the thermal decomposition of TKX-50 components, and this would be beneficial to promote the burning rate of propellants containing TKX-50 components. © 2022 Society of Chemical Industry (SCI).
研究领域:
材料科学
·
推进剂化学
✓ 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）