PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2025
·
IF 2.9
Chunyu Song,Xuan Zhang,Chenglong Qiu,Yong Yang
Polyacetylenes (PDAs) with superior thermochromic properties serve as effective safeguards against equipment overheating and personal safety hazards. However, their responsiveness to medium-to-high temperature ranges still poses a significant challenge. In this study, a series of thermochromic bis-polyacetylene (Bis-PDA-1, Bis-PDA-2, Bis-PDA-3) linked with symmetric aromatic amides consisted of benzene, biphenyl and bipyridine at the center have been developed. These polymers can undergo multi-step color transitions in response to thermal stimulation ranged from 80 °C to 110 °C, and after multiple heating and cooling cycles, the samples still show reversible thermochromic characteristics. The thermochromic Bis-PDAs exhibit exceptional sensitivity with instantaneous color transitions (<1 s) at 110°C. The temperature-dependent high-contrast chromatic variations significantly improve visual discernibility in practical applications. In particular, Bis-PDA-1 displays thermochromic behavior when heated up to 110 °C, which presents a higher color transition temperature than Bis-PDA-2 and Bis-PDA-3. This is attributed to the low steric hindrance of Bis-PDA-1 at the molecular center, which enhances the intermolecular hydrogen bonding. These Bis-PDAs designed in this work present superior practicability in the field of thermal management, which also provide a guideline for the tuning of color-transition behaviors of thermochromic materials.
研究领域:
材料科学
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高分子化学
·
热致变色
·
传感器
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纳米技术
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产品关联
DOI
PubMed
高影响因子
Catalysis Science & Technology
·
2015
·Vol. 6
·期 9
·3027-3037
·
IF 5.426
Yanan Liu,Yufei He,Daran Zhou,Junting Feng,Dianqing Li
Aiming at the preparation of catalysts with well-controlled structures, bimetallic PdCu catalysts containing only small amounts of Pd were prepared by two different methods for partial hydrogenation of acetylene. The highly dispersed and stable PdCu catalyst with the Pd : Cu atomic ratio of 1 : 40 was obtained from a Pd(OH)2/CuMgAl hydrotalcite (HT) precursor by a modified co-precipitation method. The obtained PdCu catalyst possessed uniform PdCu nanoalloys with an average size of 1.8 ± 0.3 nm. As a comparison, the impregnation method was also employed to prepare bimetallic PdCu catalysts and it was confirmed that the Pd-rich(core)–Cu-rich(shell) structure was dominant. Under identical reaction conditions, approximately 100% conversion and 82% selectivity at 100 °C were achieved using the PdCu nanoalloy catalyst which were 23% and 12% higher than those of the Pd-rich(core)–Cu-rich(shell) catalyst. The preferable activity was ascribed to the homogeneous nanoalloy structure and small size effect. The enhanced selectivity was attributed to the strong synergistic effect of PdCu. More significantly, this superior catalytic performance can be retained after 48 h of continuous reaction due to the excellent resistibility against carbon deposition and the confinement effect.
研究领域:
催化化学
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材料科学
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有机合成
✓ 已验证
DOI
高影响因子
COMBUSTION AND FLAME
·
2022
·
IF 5.767
Hanfeng Jin,Weiye Chen,Lili Ye,Hao Lou,Qiang Xu,Beibei Feng,Zhandong Wang,Aamir Farooq
The reaction between phenyl radical and phenylacetylene is a prototype for the reactions of aryl radicals and alkynyl peri‑condensed aromatic hydrocarbons (PCAHs), which may help explain the dimerization of PCAHs by covalent bond with acetylene assistance. In this work, we have experimentally and theoretically investigated reaction kinetics of phenyl radical and phenylacetylene. Gas chromatography-mass spectrometry (GC–MS) is applied to separate and identify molecular structures of reaction products in a jet-stirred reactor (JSR). Diphenylacetylene is observed as the major product of this reaction, which shows dominant concentration near 1000 K. Formation of phenanthrene increases with temperature, while 9-methylene-fluorene is a minor product, and 2-ethynyl-biphenyl is negligible. The potential energy surface and rate coefficients of phenyl and phenylacetylene reaction are calculated by quantum chemistry and transition state theory. 1,2-Diphenylvinyl is the only resonance-stabilized radical (RSR) among the adducts formed via all six possible addition reaction channels. Its formation reaction channel has a much lower energy barrier and deeper potential well and, therefore, it wins the competition in the reaction of phenyl and phenylacetylene at combustion-relevant intermediate temperatures.
研究领域:
燃烧化学
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物理化学
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化学动力学
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产品关联
DOI
高影响因子
RAPID COMMUNICATIONS IN MASS SPECTROMETRY
·
2020
·Vol. 34
·期 21
·e8899
·
IF 2.2
Hanfeng Jin,Jiuzhong Yang,Aamir Farooq
Rationale Aromatic hydrocarbons play an important role in the formation and growth of polycyclic aromatic hydrocarbon (PAH) and soot particles. Measurements of their absolute photoionization cross-sections (PICSs), that benefit the quantitative investigation of mass spectrometry, are still lacking, however. Methods PICSs of some aromatic hydrocarbons were measured with tunable synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS). Nitric oxide and benzene were chosen as standard references for PICS calibration, since their photoionization cross-sections are well documented in the literature. Binary liquid mixtures of the investigated molecules and their specific solvents were used in the measurements. Results The investigated aromatics include naphthalene, phenanthrene, 1-methylnaphthalene, indene, 2-/3-/4-methylphenylacetylene, 2-methylindene, diphenylacetylene, 1-/2-ethynylnaphthalene and acenaphthylene. Photo-induced fragments from the molecules were also observed with increasing photon energy. Conclusions Based on our measurements and literature data, PICSs of most aromatic molecules have very similar values beyond their ionization energies. However, molecules that contain the phenylacetylene structure have PICSs higher than other aromatics.
研究领域:
分析化学
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质谱学
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大气化学
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环境科学
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产品关联
DOI
PubMed
高影响因子
Polymers
·
2020
·Vol. 12
·期 3
·684
·
IF 3.426
Qilin Mei,Honghua Wang,Xiaocheng Chen,Ying Wang,Zhixiong Huang
With the rapid development of thermal protection systems for the aerospace industry and power electronics, polyarylacetylene (PAA) resin plays an important role because of its good mechanical properties, high glass transition temperature (Tg), low water absorption, high char yield (Yc), and the fact that there is no byproduct released in the curing process. In order to further improve the thermal property of PAA based FRP for the thermal protection field, the introduction of a zirconium element into arylacetylene is promising. In this paper, zirconium modified arylacetylene (ZAA) resin was prepared by two-step synthesis. The FTIR analysis characterized its molecular structure and confirmed the products. The viscosity of ZAA was about 6.5 Pa·s when the temperature was above 120 °C. The DSC analysis showed that the ZAA had a low curing temperature, and its apparent activation energy was 103.86 kJ/mol in the Kissinger method and 106.46 kJ/mol in the Ozawa method. The dielectric constant at 1 MHz of poly(zirconium modified arylacetylene) (PZAA) was 3.4. The TG analysis showed that the temperatures of a weight loss of 5% (Td5) and char yield (Yc) at 800 °C of PZAA were 407.5 °C and 61.4%, respectively. The XRD results showed the presence of SiO2and ZrO2in the PZAA residue after ablation. The XRF results showed that the contents of SiO2and ZrO2in PZAA residual after ablation were, respectively, 15.3% and 12.4%. The SEM showed that the surface of PZAA after ablation had been covered with a dense and rigid ceramic phase composed of ZrO2and SiO2. Therefore, the introduction of Zr into arylacetylene greatly improved the densification of the surface after ablation, and improved the heat resistant property.Keywords:arylacetylene;zirconium;thermal stability;ceramifiable mechanism
研究领域:
材料科学
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航空航天工程
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 137
·期 39
·49167
·
IF 2.52
Jiaqi Shang,Song Mei,Danyu Zhao,Jianping Deng
Optically active hybrid particles consisting of chiral organic component and inorganic component integrate the individual advantages of the components in one entity. This article reports a new type of optically active hybrid particles constructed by helical substituted polyacetylene and octavinyl polyhedral oligomeric silsesquioxane (OvPOSS). The hybrid particles were prepared in a two-step process. First, helical substituted polyacetylene with pendent vinyl groups was synthesized and named as macromonomer (MM). Then, hybrid particles were prepared from MM and OvPOSS by free radical suspension polymerization, in which OvPOSS acted simultaneously as comonomer and crosslinking agent. OvPOSS and MM together constituted a crosslinked network and formed spherical, porous hybrid particles. The resulting hybrid particles exhibited the desired optical activity, according to circular dichroism spectroscopy measurement. As an organic/inorganic hybrid molecule itself, OvPOSS moderately improved the thermostability of the organic component and meanwhile increased the porosity of the hybrid particles. It also helped to tune the surface morphology of the hybrid particles. The present study provides a novel class of optically active hybrid particles, and the preparation strategy may further work as a versatile platform for developing novel chiral hybrid materials.
研究领域:
材料科学
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有机化学
✓ 已验证
DOI
高影响因子
Nature Catalysis
·
2021
·Vol. 4
·期 7
·565-574
·
IF 41.813
Shi Run,Wang Zeping,Zhao Yunxuan,Waterhouse Geoffrey I. N.,Li Zhenhua,Zhang Bikun,Sun Zhimei,Xia Chuan,Wang Haotian,Zhang Tierui
The selective hydrogenation of acetylene to ethylene in ethylene-rich gas streams is an important process in the manufacture of polyethylene. Conventional thermal hydrogenation routes require temperatures above 100 °C and excess hydrogen to achieve a satisfactory C 2 H 2 conversion efficiency. Here, we report a room-temperature electrochemical acetylene reduction system based on a layered double hydroxide (LDH)-derived copper catalyst that offers an ethylene Faradaic efficiency of up to ~80% and inhibits alkane and hydrogen formation. The system affords an acetylene conversion of over 99.9% at a flow rate of 50 ml min −1 in a simulated gas feed, yielding high-purity ethylene with an ethylene/acetylene volume ratio exceeding 10 5 and negligible residual hydrogen (0.08 vol.%). These acetylene conversion metrics are superior to most other state-of-the-art strategies. The findings therefore conclusively demonstrate an electrochemical strategy as a viable alternative to current technologies for acetylene-to-ethylene conversions with potential advantages in energy and atom economies.
研究领域:
化工工程
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电化学
·
催化
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2021
·
IF 19.503
Kaiyi Su,Yehong Wang,Chaofeng Zhang,Zhuyan Gao,Jianyu Han,Feng Wang
Herein, we reported the tuning of dominant products in the photocatalytic hydrogen transfer reaction over Pt/Nb 2 O 5 photocatalysts, using a support-induced modification strategy. In the photocatalytic conversion of phenylacetylene with ethanol as a probe reaction, the dominant product was styrene over Pt/2D Nb 2 O 5 nanoplates; in contrast, H 2 was the main product over the Pt/bulk Nb 2 O 5 . Compared to the metallic Pt species over bulk Nb 2 O 5 , the positively charged Pt (Pt δ+ ) species over 2D Nb 2 O 5 nanoplates contributed to the reduction of phenylacetylene, which was revealed by CO adsorbed Fourier transform infrared spectra. Furthermore, the present Pt δ+ species were due to the formation of Pt δ+ –O–Nb structure via oxygen transfer of 2D Nb 2 O 5 nanoplates, which was verified by the results of X-ray photoelectron spectra and H 2 temperature-programmed reduction. This work sheds light on the design and application of Nb-based catalysts in the transfer hydrogenation of organics in photocatalysis.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2023
·Vol. 28
·期 5
·2335
·
IF 4.6
Hongquan Kang,Jianzhou Wu,Baohui Lou,Yue Wang,Yilin Zhao,Juanjuan Liu,Shihui Zou,Jie Fan
The rational regulation of catalyst active sites at atomic scale is a key approach to unveil the relationship between structure and catalytic performance. Herein, we reported a strategy for the controllable deposition of Bi on Pd nanocubes (Pd NCs) in the priority order from corners to edges and then to facets (Pd NCs@Bi). The spherical aberration-corrected scanning transmission electron microscopy (ac-STEM) results indicated that Bi2O3with an amorphous structure covers the specific sites of Pd NCs. When only the corners and edges of the Pd NCs were covered, the supported Pd NCs@Bi catalyst exhibited an optimal trade-off between high conversion and selectivity in the hydrogenation of acetylene to ethylene under ethylene-rich conditions (99.7% C2H2conversion and 94.3% C2H4selectivity at 170 °C) with remarkable long-term stability. According to the H2-TPR and C2H4-TPD measurements, the moderate hydrogen dissociation and the weak ethylene adsorption are responsible for this excellent catalytic performance. Following these results, the selectively Bi-deposited Pd nanoparticle catalysts showed incredible acetylene hydrogenation performance, which provides a feasible perspective to design and develop highly selective hydrogenation catalysts for industrial applications.Keywords:acetylene hydrogenation;active sites;selective deposition;palladium;bismuth
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CARBON
·
2019
·
IF 7.466
Yudi Mo,Junchen Liu,Chao Meng,Min Xiao,Shan Ren,Luyi Sun,Shuanjin Wang,Yuezhong Meng
The low electronic conductivity and poor Li + diffusion coefficient of conventional LiFePO 4 (LFP) materials severely impede its high-rate applications for lithium-ion batteries (LIBs). To break these limits, one novel poly(1,3-diethynylbenzene) (PAB) acetylenic carbon-rich polymer with extremely high-carbon content (96.75 wt%) and good solubility has been prepared by an oxidative coupling reaction. One definite advantage is that this carbon-rich PAB polymer will release, upon pyrolysis , very low amounts of gas, forming therefore uniform and dense highly conductive carbon network. Besides, the specific resistivity of continuous PAB-C layer can be as low as ∼0.01 Ω cm, which can effectively improve electrical conductivity and maintain mechanical integrity of LFP cathode. As a result, the prepared LFP@PAB-C nanocomposites with approximately 3.8 wt% carbon content and 2.5 nm carbon layer exhibit an excellent high-rate capability, e.g. even at a considerable discharge rate of 50 C, while the capacity can still be remained at 129.6 mA h g −1 . Moreover, the LFP@PAB-C nanocomposites also reveal a remarkable cycling stability with as high as 100.6% capacity retention at 20 C over 1000 cycles. This kind of LFP@PAB-C composite was demonstrated to be an ideal cathode material for high-power LIBs.
研究领域:
材料科学
·
电化学
·
能源存储
✓ 已验证
DOI
高影响因子
Polymers
·
2020
·Vol. 12
·期 5
·999
·
IF 3.426
Qilin Mei,Honghua Wang,Danliao Tong,Jiuqiang Song,Zhixiong Huang
Benzoxazine resin has been paid more attention in the fields of aviation, electronics, automobiles and new energy industries because of its excellent comprehensive performance. Further application is limited, however, by shortcomings such as high brittleness and high curing temperature. Furthermore, higher thermal stability is imperiously demanded in special areas. Incorporating both an acetylene group and silicon into the benzoxazine monomer is a promising possible solution to improve the curing processability, thermal properties and toughness of benzoxazine. In this paper, an acetylene-functional/silicon-containing benzoxazine monomer was prepared by two-step synthesis, and acetylene-functional benzoxazine was also prepared as a comparison. FTIR and1H NMR confirmed the molecular structure of acetylene-functional/silicon-containing benzoxazine. Differential scanning calorimetry (DSC) analysis showed that the initial and peak degradation temperatures of acetylene-functional/silicon-containing benzoxazine were decreased by 21 °C and 18 °C compared with acetylene-functional benzoxazine, respectively. The apparent activation energy of the curing reaction of acetylene-functional/silicon-containing benzoxazine was 83.1 kJ/mol, which was slightly lower than acetylene-functional benzoxazine (84.7 kJ/mol). TGA results showed that the acetylene-functional/silicon-containing benzoxazine had a higher thermal stability than acetylene-functional benzoxazine. The temperatures of 5% weight loss of acetylene-functional/silicon-containing benzoxazine were 380 °C in nitrogen and 485 °C in air, and the char yield at 1000 °C was 80% in nitrogen and 21% in air, respectively. The results of mechanical properties showed that the impact strength of acetylene-functional/silicon-containing benzoxazine was higher than acetylene-functional benzoxazine by 35.4%. The tensile and flexural strengths of acetylene-functional/silicon-containing benzoxazine were slightly higher than that of acetylene-functional benzoxazine.Keywords:benzoxazine;acetylene;silicon;curing kinetics;thermal stability
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Food Measurement and Characterization
·
2024
·
IF 2.9
Pang Wanyu,Gao Yali,Chang Xile,Hu Tuoping,Hu Zhiyong,Ma Xuemei
An electrochemical sensing platform based on in-situ acetylene black (AB) template growth ZIF-8 for trace catechin detection in green tea was proposed. Here, the ZIF-8/AB/carbon paper (CP) electrode was constructed by two-step in-situ growth method and hydrothermal method. The characterization showed that AB molecule was well distributed in ZIF-8 pore with large surface area. ZIF-8/AB/CP electrode showed good electrochemical performance for catechin detection, which benefited from the ZIF-8 with larger surface and AB with excellent conductivity. The results showed that ZIF-8/AB/CP electrode was linear in the range of 0.01–200 µM, and the low detection limit for catechin detection was 43.7 nM. ZIF-8/AB/CP also had good reproducibility, anti-interference ability and stability. In addition, the sensor achieved hight-recovery and accuracy in detecting catechin in green tea. As far as we know, our work first reported that ZIF-8/AB composite was synthesized by in-situ growth method as an electrochemical sensing material for the detection of catechin in green tea, which will provide some theoretical analysis and experimental experience for designing and developing electrochemical sensor for the analysis of trace catechin.
研究领域:
分析化学
·
材料科学
·
食品科学
✓ 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）