MACROMOLECULES
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2022
·
IF 6.057
Gaopeng Shi,Xiaoning Geng,Yuanbiao Liu,Guozhang Wu
Enthalpy hysteresis (ΔHR), an easily accessible quantity determined from a well-defined cooling and subsequent heating cycle of heat capacity curves, was recently reported to bear a proportional relationship with the α-related excess entropy of polymers at glass transition temperature( Tg). The kinetic fragility m of polymers was thus verified to link with thermodynamic parameters of Tg·ΔCp/ΔHR, as predicted by the Adam–Gibbs equation. In this work, enthalpy hysteresis of poly(n-alkyl methacrylate)s was investigated systematically to clarify whether ΔHR is influenced by multifarious non-α-related contributions. The results showed that the ΔHR for higher poly(n-alkyl methacrylate)s is abnormally suppressed, as manifested by failure of the theoretic correlation between m and Tg·ΔCp/ΔHR. The anomalous suppression appears non-related to the βJG relaxation but stems from nanophase separation of the alkyl sidechains. Once the PE-like nanophase is completely destroyed, either by increasing the steric hindrance of side groups or by introducing small molecule-bridged hydrogen bonds, ΔHR recovers, and the theoretic correlation between m and Tg·ΔCp/ΔHR is re-established. Further experiments revealed that the abnormal ΔHR suppression occurs only when the periodicity of phase separation is comparable to the size of the cooperative rearrangement region of bulk α relaxation at Tg. Accordingly, the deviation of m and Tg·ΔCp/ΔHR correlations from the theoretic prediction must be related to the existence of two different but partly coupled glass transitions in higher poly(n-alkyl methacrylate)s. The extremely hindered and confined glass transition in the PE-like nanodomains is likely to cause the anomalous suppression of global enthalpy hysteresis.
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Materials Today Energy
·
2022
·
IF 9.257
Luyao Zheng,Cong Liu,Sinong Wang,Boxu Gao,Xueliang Fan,Shuyu Xu,Yingshuai Jia,Yahong Zhang,Qingsheng Gao,Xiaoming Cao,Yi Tang
Transition metal carbides (TMCs) are regarded as cost-efficient and stable electrocatalysts for hydrogen evolution reaction (HER). Nitrogen doping into nanosized TMCs in a control manner (e.g. doping amount and site) is one of the most effective routes to intrinsically enhance the activity and durability owing to the ameliorated Mo–H strength and amplified active sites. Herein, an approach based on reticular chemistry is developed to synthesize nanosized N-doped Mo 2 C embedded in porous carbon (N–Mo 2 C/PC), via pyrolyzing a hybrid precursor consisting of highly-dispersed molybdates within melamine-benzenetricarboxylic acid supermolecule networks. With optimal N-doping, the N–Mo 2 C/PC electrocatalyst exhibits an excellent HER stability and activity with overpotential of 109 mV at 10 mA cm −2 in 0.5 M H 2 SO 4 , as well as 100 mV at 10 mA cm −2 in 1.0 M KOH. Density functional theory calculations confirm that the appropriate N doping on the surface of Mo 2 C nanoparticles would accelerate the HER process via weakening the Mo–H bond strength and lowering the H–H coupling barrier. Furthermore, Mo 2 C nanoparticles loaded on carbon cloth with high HER activity can also be successfully achieved by this strategy. This work paves a universal way to design active sites-enriched TMCs with high performance in energy conversion and storages.
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Frontiers of Optoelectronics
·
2022
·Vol. 15
·期 1
·1-10
·
IF 0
Jiang Mengjia,Li Shuyu,Zhen Chun,Wang Lingsong,Li Fei,Zhang Yihan,Dong Weibing,Zhang Xiaotao,Hu Wenping
Simultaneously realizing the optical and electrical properties of organic materials is always challenging. Herein, a convenient and promising strategy for designing organic materials with integrated optoelectronic properties based on cocrystal engineering has been put forward. By selecting the fluorene (Flu) and the 7,7′,8,8′-tetracyanoquinodimethane (TCNQ) as functional constituents, the Flu-TCNQ cocrystal prepared shows deep red emission at 702 nm, which is comparable to the commercialized red quantum dot. The highest electron mobility of organic field-effect transistor (OFET) based on Flu-TCNQ is 0.32 cm 2 V −1 s −1 . Spectroscopic analysis indicates that the intermolecular driving force contributing to the co-assembly of Flu-TCNQ is mainly charge transfer (CT) interaction, which leads to its different optoelectronic properties from constituents. Graphical Abstract
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PubMed
CHEMOSPHERE
·
2022
·
IF 8.943
Jian Zhao,Shangbiao Fang,Weixiao Qi,Huijuan Liu,Jiuhui Qu
Biodegradation is regarding as the most important organic micro-pollutants (OMPs) removal mechanism during riverbank filtration (RBF), but the OMPs co-metabolism mechanism and the role of NH 4 + -N during this process are not well understood. Here, we selected atenolol as a typical OMP to explore the effect of NH 4 + -N concentration on atenolol removal and the role of ammonia oxidizing bacteria (AOB) in atenolol biodegradation. The results showed that RBF is an effective barrier for atenolol mainly by biodegradation and adsorption. The ratio of biodegradation and adsorption to atenolol removal was dependent on atenolol concentration. Specifically, atenolol with low concentration (500 ng/L) is almost completely removed by adsorption, while atenolol with higher concentration (100 μg/L) is removed by biodegradation (51.7%) and adsorption (30.8%). Long-term difference in influent NH 4 + -N concentrations did not show significant impact on atenolol (500 ng/L) removal, which was mainly dominated by adsorption. Besides, AOB enhanced the removal of atenolol (100 μg/L) as biodegradation played a more crucial role in removing atenolol under this concentration. Both AOB and heterotrophic bacteria can degrade atenolol during RBF, but the degree of AOB's contribution may be related to the concentration of atenolol exposure. The main reactions occurred during atenolol biodegradation possibly includes primary amide hydrolysis, hydroxylation and secondary amine depropylation. About 90% of the bio-transformed atenolol was produced as atenolol acid. AOB could transform atenolol to atenolol acid by inducing primary amide hydrolysis but failed to degrade atenolol acid further under the conditions of this paper. This study provides novel insights regarding the roles played by AOB in OMPs biotransformation during RBF.
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FUEL
·
2022
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IF 8.035
Ben Chen,Bowen Hui,Yuting Dong,Qiang Sheng,Xiang Li,Qinglan Hao,Chunjing Liu
The SiO 2 - and MCM-41-supported Ni catalysts were prepared by an incipient wetness impregnation method and their performance in the hydrogenation of liquid organic hydrogen carrier were evaluated using N-ethylcarbazole (NEC) as model compound. Ni particles were mainly located on the external surface of the SiO 2 -supported Ni catalysts. Both Ni particles on the external surface and filled in the mesopores of MCM-41 were found in the MCM-41-supported catalysts. The reduction of surface Ni particles occurred at low temperature (ca. 365 °C), but the complete reduction of Ni particles in the mesopores of MCM-41 required high temperature (ca. 555 °C). The MCM-41-supported Ni particles possessed lower electron densities than the SiO 2 -supported ones. The surface Ni particles showed the same activity in the hydrogenation of NEC, which were more active than those in the mesopores of MCM-41. A correlation between the electron density of Ni particles and their selectivity was observed. The higher the electron density of Ni particles, the higher the selectivity to the fully hydrogenated product (dodecahydro-N-ethylcarbazole) is.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2022
·
IF 5.518
Fangfei Meng,Ying Xu,Zhaoqiang Wu,Hong Chen
A simple and convenient strategy for fabricating superhydrophilic antifogging coatings was developed by poly( N -hydroxyethyl acrylamide) (PHEAA) composites enhanced by zwitterionic sulfobetaine silane (SBSi)-modified SiO 2 nanoparticles . These antifogging coatings can be easily obtained by coating PHEAA composites on substrates at room temperature and then cured by thermal treatment. Such transparent coatings exhibited excellent antifogging performance under both hot and cold fogging conditions. Additionally, the coatings have good adhesion against the cross-cut test and thermal stability in the hot water resistance test. The present PHEAA composite coatings are promising for real-world antifogging applications.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2022
·Vol. 33
·期 6
·3237-3249
·
IF 2.779
Wang Siyu,Guo Jiaxiong,Lin Zhidong,Liu Liming,Hui Yuchong,Zhang Xiaowen
A series of very small grain Au/SnO 2 composites were synthesized by a facile hydrothermal method. The microstructure of the Au/SnO 2 composites were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscopy, and nitrogen adsorption–desorption experiment. The composites were composed of 20–30 nm spherical nanoparticles, which are hierarchical structure composed of 8 nm Au cores and 5 nm SnO 2 nanograins. The composites were porous material with large specific surface area. The sensors based on the Au/SnO 2 composites showed high sensitivities and selectivity to n -butanol at low working temperature with fast response. Among these sensors, the 1.5 wt% Au/SnO 2 -based sensor shows the highest response (2662.8) to 100 ppm n -butanol with the response time of 35 s at 80 °C. The excellent low-temperature gas-sensing properties of the Au/SnO 2 sensors can be ascribed to the synergetic effect of high surface energy of small SnO 2 nanograins and catalysis of gold nanoparticles. Our study demonstrates that controlling the grain size of SnO 2 and Au nanoparticle-assisted gas sensing are effective methods to improve the sensing properties of SnO 2 at low working temperature. The 1.5 wt% Au/SnO 2 composite is a potential low-temperature gas-sensing material for n -butanol detection.
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SOLAR ENERGY MATERIALS AND SOLAR CELLS
·
2021
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IF 7.267
Ping Hu,Yang Feng,Qi Li,Chuan-Huang Lin,Yu-Hao Ning,Yi-Ting Li,Lin-Ping Yu,Zhong Cao,Ju-Lan Zeng
Microencapsulation of phase change materials (PCMs) with functional shell materials such as luminescent material could endow the obtained microencapsulated PCMs (MPCMs) with improved latent heat storage properties. The PCM core in turn could protect the luminescence shell from large temperature shifting and thus improve its performance. In this work, a series of MPCMs derived from n -octadecane (ODE) core and CaF 2 shell were synthesized via a self-assembly method. The effects of the preparation conditions, including the core/shell mass ratio, the dosage of the emulsifier (styrene-maleic anhydride copolymer , SMA) and the dosage of the chelator (Na 3 Cit), on the properties of the prepared ODE@CaF 2 MPCMs were investigated and the optimal preparation condition was obtained. The MPCM obtained according to the optimal procedure (MPCM1) exhibited an encapsulation ratio of 54.02% and a latent heat of 131 J/g with negligible leakage. It also possessed excellent thermal reliability and significantly improved thermal conductivity . The MPCM1 could not only be utilized as good latent heat storage material and thermal regulation material, but also provided one new idea to prevent the thermal quenching of luminescence materials. In addition, this work could shed some light on the high-value utilization of recovered fluorine resources.
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ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2023
·
IF 11.4
Zimou Feng,Xunda Feng,Xinglin Lu
Fouling-resistant surfaces are needed for various environmental applications. Inspired by superhydrophilic N-oxide-based osmolytes in saltwater fish, we demonstrate the use of a trimethylamine N-oxide (TMAO) analogue for constructing fouling-resistant surfaces. The readily synthesized N-oxide monomer of methacrylamide is grafted to filtration membrane surfaces by surface-initiated atom transfer radical polymerization (SI-ATRP). Successful grafting of the amine N-oxide brush layer as confirmed by material characterization endows the surface with increased hydrophilicity, reduced charge, and decreased roughness. Notably, the introduction of the N-oxide layer does not compromise transport properties, i.e., water permeability and water-salt selectivity. Moreover, the modified membrane exhibits improved antifouling properties with a lower flux decline (32.1%) and greater fouling reversibility (18.55%) than the control sample (45.4% flux decline and 3.26% fouling reversibility). We further evaluate foulant–membrane interaction using surface plasmon resonance (SPR) to relate the reduced fouling tendency to the synergic effects of surface characteristic changes after amine N-oxide modification. Our results demonstrate the promise and potential of the N-oxide-based polymer brushes for the design of fouling resistance surfaces for a variety of emerging environmental applications.
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COMBUSTION AND FLAME
·
2023
·
IF 4.4
Bingzhi Liu,Qimei Di,Maxence Lailliau,Nesrine Belhadj,Philippe Dagaut,Zhandong Wang
Attractiveness in advanced low-temperature combustion engines drives a constantly updated understanding of low-temperature oxidation chemistry. In this work, the low-temperature oxidation chemistry of n -pentane in two jet-stirred reactors at atmospheric pressure and in the temperature range of 500–825 K was investigated using combined analysis methods of synchrotron vacuum ultraviolet photoionization mass spectrometry , gas chromatography, and Fourier transform infrared spectroscopy. Furthermore, the gaseous mixture from JSR was collected in acetonitrile for subsequent product characterization using flow injection analysis , high-pressure and ultra-high-pressure liquid chromatography coupled to a Thermo Scientific™ Orbitrap® Q-Exactive high-resolution mass spectrometry. Numerous intermediate species were identified by these analytical methods, which contributed to unraveling the low-temperature oxidation reaction network of n -pentane. A detailed n -pentane model was tentatively developed to reduce deviations between experimental measurements and model predictions by updating the rate constants of C 5 keto-hydroperoxide decomposition, C 5 hydroperoxy cyclic ether decomposition, and Korcek reactions of C 5 keto-hydroperoxide, and by introducing pressure-dependent rate constants for the reaction classes of Q ˙ OOH + O 2 , Q ˙ OOH decompositions, concerted HȮ 2 -elimination of RȮ 2 , C 5 keto-hydroperoxide decomposition, C 5 hydroperoxy cyclic ether decomposition, and Korcek reactions of C 5 keto-hydroperoxide, and by adding more detailed sub-mechanisms for C 5 cyclic ethers and C 5 keto-hydroperoxides. This updated model was validated against a set of available experimental data, including jet-stirred reactor species data and ignition delay times. These exploratory updates of the kinetic model reveal the considerable influence of the rate constants of hydroperoxide decomposition and the pressure-dependent rate constants of key reaction classes on the kinetic model predictions, highlighting the future demands for high-precision quantum chemistry calculations of the pressure-dependent rate constants of the aforementioned reaction classes to reduce mechanism uncertainties and to develop accurate and robust chemical kinetic models.
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EUROPEAN JOURNAL OF MEDICINAL CHEMISTRY
·
2023
·
IF 6.7
Hewen Qian,Yuanqing Ding,Xingyu Deng,Weiwei Huang,Zhenzhen Li,Fengling Liu,Jie Zhang,Lihui Wang,Junping Liu,Yaxia Yuan,Shurong Hou,Xiabin Chen,Lei Ma
Idiopathic pulmonary fibrosis (IPF) is a severe and progressive lung disease with poor prognosis and limited treatment options. The c -Jun N-Terminal Kinase 1 (JNK1), a key component of the MAPK pathway, has been implicated in the pathogenesis of IPF and represents a potential therapeutic target. However, the development of JNK1 inhibitors has been slowed, partly due to synthetic complexity in medicinal chemistry modification. Here, we report a synthesis-accessibility-oriented strategy for designing JNK1 inhibitors based on computational prediction of synthetic feasibility and fragment-based molecule generation. This strategy led to the discovery of several potent JNK1 inhibitors, such as compound C6 (IC 50 = 33.5 nM), which exhibited comparable activity to the clinical candidate CC-90001 (IC 50 = 24.4 nM). The anti-fibrotic effect of C6 was further confirmed in animal model of pulmonary fibrosis . Moreover, compound C6 could be synthesized in only two steps, compared to nine steps for CC-90001 . Our findings suggest that compound C6 is a promising lead for further optimization and development as a novel anti-fibrotic agent targeting JNK1. In addition, the discovery of C6 also demonstrates the feasibility of synthesis-accessibility-oriented strategy in lead discovery.
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Journal of Energy Storage
·
2023
·
IF 9.4
Huizi Li,Tingyao Du,Qin Wang,Jianyu Guo,Siyong Zhang,Yan Lu
In this work, a novel carbonization method using H 2 SO 4 as dehydrating agent to prepare graphitized carbon material with O doping is firstly reported. Starch is used as the carbon source. After dehydration in H 2 SO 4 at 100 °C for 6 h, an O-enriched carbon material (OSC) is prepared. It exhibits a specific capacitance of 354 F g −1 at the current density of 1 A g −1 in 1 M H 2 SO 4 solution. After 20,000 cycles, the capacitance retention remains at 110.2 %. It is proved that appropriate amounts of doping O can provide a certain pseudocapacitance , and also improve the wettability of the material, which therefore improve the electrochemical performance of the carbon material. Further, a vapor deposition method using dicyandiamide is applied to grow N-doped carbon nanotubes on the smooth surface of the OSC, which form a three-dimensional conductive network structure on the surface and get a suitable porous structure with the specific surface area of 355 m 2 /g (NOSC). The specific capacitance of the NOSC is 759 F g −1 at the current density of 1 A g −1 in 1 M H 2 SO 4 solution. After 10,000 cycles, the capacitance retention still remains at 95.8 %. The assembled all-solid symmetric supercapacitor based on the NOSC can be operated in a 0–1.8 V voltage window. The energy density is 41.12 Wh kg −1 with a power density of 449.95 W kg −1 .
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危险品化学品经营许可证（带存储）