SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2020
·
IF 3.232
Aisen Li,Yan Liu,Changjiang Bi,Weiqing Xu,Zhiyong Ma,Haining Cui,Shuping Xu
The effects of the high pressure on two single crystals , pyrene and N , N -diphenyl-4-(pyren-1-yl)aniline (TPA-Py), were studied by in situ fluorescent and Raman spectroscopies . During the compression, the pyrene with one structureless excimer emission band showed a continuous bathochromic-shift. In contrast, with the pressure increasing to 10.36 GPa, TPA-Py previously dominated with the hybridized local and charge transfer (HLCT) excited state gradually exhibited a new band at longer wavelengths, which is assigned to a new excited state species with the intramolecular charge transfer (ICT) state, caused by the pressure-induced changes on its molecular configuration. Accompanied by the spectral changes, a sequential color variation from blue to cyan was observed, giving a change to yellow and then red. The significant broadening of the full-width half-maximum (FWHM) of the TPA-Py is observed due to the enhanced dipole-dipole interaction and the existence of pressure gradient . Both pyrene and TPA-Py showed the delayed recovery of the luminescence in the compression-decompression cycle, which results from the poor reversibility of electronic structure caused by the compression-induced piezochromic effect. Furthermore, the evolutions of the Raman spectra of pyrene and TPA-Py indicated that the pressure-induced reversible transformation is caused by the molecular conformational change. This study is a deeper understanding of the structure-property relation of the HLCT species and will be a helpful reference for the regulation of photoluminescence in these intramolecular electron donor-acceptor crystal materials.
研究领域:
材料科学
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光物理
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高压物理
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发光材料
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光谱学
✓ 已验证
DOI
高影响因子
Catalysts
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2019
·Vol. 9
·期 10
·849
·
IF 3.444
Zeyu Xue,Zhaoping Zhong,Bo Zhang,Chao Xu
To investigate the catalytic pyrolysis performance of complex metal oxide catalysts for biomass, γ-Al2O3was prepared through the precipitation method, and then ZrO2and γ-Al2O3were blended in the proportion of 2:8 using the co-precipitation method. Next, CeO2was loaded on the surface of the catalyst for further modification. The three catalysts, A, ZA and CZA, were obtained. The specific surface and acidity of the catalysts were characterized by nitrogen adsorption–desorption and NH3-Temperature Programmed Desorption (NH3-TPD) respectively. The catalytic pyrolysis performance of catalysts for bamboo residues was investigated by Pyrolysis gas chromatography mass spectrometry (Py-GC/MS). Chromatograms were analyzed for identification of the pyrolysis products and the relative amounts of each component were calculated. Experimental results indicated that catalyst A had a good catalytic activity for the fast pyrolysis of bamboo residues. The addition of ZrO2and CeO2could continuously enhance the acidity of the catalyst and further promote the pyrolysis of macromolecular compounds and deoxidation of oxygen-containing compounds. Finally, catalyst CZA, obtained by compound modification, could not only dramatically reduce the relative content of phenol, acid and aldehyde and other oxygen-containing compounds, but also achieved the maximum hydrocarbon yield of 23.38%. The catalytic performance of catalyst CZA improved significantly compared with catalyst A.Keywords:biomass;pyrolysis;catalytic cracking;Py-GC/MS;complex metal oxides
研究领域:
能源与燃料化学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2016
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IF 3.652
Shiliang Wu,Dekui Shen,Jun Hu,Huiyan Zhang,Rui Xiao
The pyrolytic characteristics of cellulose, cellobiose and glucose were examined by TG-FTIR combined with Py-GC–MS, in order to gain the effect of β -O-4 glycosidic bond on the pyrolysis process. In TG-FTIR analysis, two mass loss peaks were observed for cellobiose and glucose, indicating dehydration in low temperature stage and consequently intensive cracking of glycosidic bond and fragments for cellobiose. The samples were tested in Py-GC–MS at the temperature of 300, 500 and 900 °C according to their mass loss characteristics from TG-FTIR. Formation of furans from cellobiose, which involved the cracking of β -O-4 glycosidic bond, was prominent over other products, compared to that of cellulose and glucose. Four possible chemical pathways for the cleavage of β -O-4 glycosidic bond have been proposed with regard to the formation of furans and anhydrosugars from cellulose. Besides, another two reaction pathways leading to the formation of levoglucosan were also suggested.
研究领域:
生物质化学
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热化学转化
✓ 已验证
产品关联
DOI
高影响因子
POLYMER TESTING
·
2020
·
IF 3.275
Tao Zhou,Hang Xiao,Weifeng Peng,Bo Liang,Yao Liu,Jiangbo Lv,Jianghuai Hu,Ke Zeng,Gang Yang
The pyrolysis behaviors of l -tyrosine-based phthalonitrile(TPN) resin were investigated by thermogravimetric-Fourier transform infrared spectrometry-mass spectrometry (TG-FTIR-MS) and Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The small molecules produced during pyrolysis process of TPN resin were tracked in real time by TG-FTIR-MS. The larger molecules ( m / z > 40) from fast pyrolysis at 900 °C of the TPN resin using Py-GC/MS were identified. From TG-FTIR-MS and Py-GC/MS results, the production pathways of pyrolysis products such as CO 2 , CO, NH 3 , benzonitrile and phenol were analyzed. The possible pyrolysis mechanism of TPN resin under non-oxidizing gaseous environment was proposed. The results of this study provide the useful information for designing the molecular structure of l -tyrosine-based polymers which possessing high thermal stability.
研究领域:
材料科学
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化学工程
✓ 已验证
DOI
高影响因子
Chemistry-An Asian Journal
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2017
·Vol. 12
·期 10
·1095-1103
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IF 4.083
He Li,Chunzhi Li,Jian Chen,Lina Liu,Qihua Yang
Graphical Pore it on : A bifunctionalized pyridine–zinc-based porous organic polymer, Py-Zn@MA, is synthesized and used for the co-catalyst-free cycloaddition of epoxides with CO 2 . The high activity of Py-Zn@MA is attributed to its bifunctional nature with ZnBr 2 and pyridine activating the epoxide in a cooperative way. The catalyst can be easily prepared on a large scale and shows good substrate universality for the cycloaddition of epoxides. The synthesis of solid catalysts for the co-catalyst-free cycloaddition of CO 2 has attracted much attention. Herein, we report a hierarchical porous organic polymer, Py-Zn@MA, that is able to catalyze the cycloaddition reaction of epoxides and CO 2 without using any additives or co-catalyst to afford turnover frequency (TOF) values as high as 250 and 97 h −1 at 130 °C by using pure and diluted CO 2 (simulating flue gas), respectively. These results are superior to those obtained from previously reported heterogeneous co-catalyst-free systems. The high activity of Py-Zn@MA is mainly attributed to its bifunctional nature with ZnBr 2 and pyridine activating the epoxide in a cooperative way. Notably, Py-Zn@MA can be easily prepared on a large scale without using any catalyst and the chemicals are cost effective. Moreover, Py-Zn@MA shows good substrate universality for the cycloaddition reactions of epoxides. Our designed porous organic polymer Py-Zn@MA material has the potential to serve as an efficient catalyst for the direct conversion of flue gas with epoxides into value-added cyclic carbonates.
研究领域:
催化化学
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材料科学
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环境化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Processes
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2022
·Vol. 10
·期 10
·1970
·
IF 3.352
Xuan Zhou,Hongling Pan,Shuixiang Xie,Guotao Li,Zhicai Du,Xiang Wang,Yan Luo
The aim of this research is to design and synthesize an efficient catalyst to enhance high value-added products, such as aromatic hydrocarbons and phenols, from the catalytic fast pyrolysis (CFP) of different types of forestry and agricultural residues. All three biomasses (rape straw, wheat straw, and bamboo powder) had no aromatic production via thermal pyrolysis alone; however, the aromatic selectivity and monocyclic aromatic selectivity were largely enhanced using ZSM-5, with suitable silica-alumina ratios and Ni loadings. Specifically, for rape straw, the optimum catalyst was 15 wt.% Ni/ZSM-5 (silica-aluminum ratios = 85), and the selectivity of aromatic hydrocarbons was achieved at 39%, of which 71% were monocyclic aromatic hydrocarbons. For wheat straw, the optimum catalyst was 10 wt.% Ni/ZSM-5 (silica-aluminum ratios = 18), and the selectivity of aromatic hydrocarbons was 67%, of which 55% were monocyclic aromatic hydrocarbons. For bamboo powder, the optimum catalyst was 10 wt.% Ni/ZSM-5 (silica-aluminum ratios = 18), and the selectivity of aromatic hydrocarbons was achieved at 21%, of which 80% were monocyclic aromatic hydrocarbons. Meanwhile, biomass types have significant effects on the pyrolyzed product distribution due to their different components. Cellulose and hemicellulose promoted the production of aromatic hydrocarbons, while lignin enhanced the production of phenols. The promotion of phenol by Ni was better and more efficient than that by the molecular sieve.Keywords:catalytic fast pyrolysis;forestry and agricultural residues;Ni/ZSM-5;aromatic hydrocarbons;phenols;Py-GC/MS
研究领域:
能源与环境科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2016
·
IF 3.652
Kuan Ding,Zhaoping Zhong,Bo Zhang,Jia Wang,Addy Min,Roger Ruan
Pyrolysis of waste tire with HY, HZSM-5 (HZ) and purified attapulgite (PA) catalysts to produce valuable aromatic hydrocarbons has been carried out in a Pyrolyzer- Gas Chromatograph/Mass Spectrum (Py-GC/MS) reactor. Likewise, d -limonene and polybutadiene rubber (BR), which played important roles in the pyrolysis process of waste tire, has also been pyrolyzed in the Py-GC/MS reactor with these catalysts. Based on the product distribution, the catalytic pyrolysis mechanisms of d -limonene were proposed, while those of BR were extended. With these mechanisms, the catalytic pyrolysis characteristics of waste tire could be explained reasonably. Results showed that HY promoted a dramatic increase of aromatics from pyrolysis of d -limonene and BR, leading to the considerable growth of aromatics in the degraded products of waste tire. The shape selectivity of HZ to mono-cyclic aromatics performed effectively in the pyrolysis of BR, yet it exhibited a weak performance in the pyrolysis of d -limonene. As a result, upon the catalytic pyrolysis of waste tire, HZ was inferior to HY in the aromatization ability. However, the selectivity of HZ to BTXE (benzene, toluene, xylene and ethylbenzene) was superior to that of HY. PA performed a weaker catalytic ability in promoting the production of aromatics during the pyrolysis of d -limonene, BR and waste tire.
研究领域:
化学工程
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
Science China-Technological Sciences
·
2023
·Vol. 66
·期 8
·2258-2270
·
IF 4.6
Wang Na,Gu An,Lei Yong
Lacquer is the main raw material of lacquerware, while UV-irradiation is an important factor leading to its aging. In order to investigate the aging behavior of urushi lacquer film under UV-irradiation, and to propose parameters that can be used to evaluate its aging degree, the micro-UV/Py-GC/MS system has been applied in the present work to enrich and identify volatile products released by urushi film during aging on the one hand, and to investigate micro-amount and conventional urushi films with different aging degrees on the other hand, in addition, representative historical samples have also been investigated. Volatile products released by urushi film demonstrate that during UV-irradiation, polysaccharides wrapping urushiol polymer would be first degraded to generate furans and alcohols, and then urushiol polymer would undergo photo-oxidation and break of molecular chain, mainly generating oxidation products including aldehydes, organic acids, and ketones, as well as a small number of alkyl benzenes and hydrocarbons. Py-GC/MS analysis of micro-amount urushi films with different aging degrees indicates that UV-irradiation is more destructive to aliphatic chains in urushiol polymer, but it also can accelerate the polymerization of micro-amount urushi film. Py-GC/MS analysis of conventional urushi films indicates that with the increase of aging degree, the total chromatographic peak area ratio of hydrocarbons to benzene derivatives gradually increases, the peak area ratio of 3-pentadecenyl-catechol to 3-pentadecyl-catechol gradually decreases, and the peak area ratio of aging products of urushiol to 3-pentadecyl-catechol gradually increases. The above parameters were further used to evaluate the aging degree of two urushi-contained samples separately collected from the surface and interior of a carved lacquer panel in the Forbidden City, and evaluation results are in accord with the natural aging law and further verify the reliability of the proposed parameters. Research results of the present work can lay a foundation for the in-depth study of the UV-irradiation aging mechanism of urushi.
研究领域:
材料科学
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文物保护
✓ 已验证
产品关联
DOI
高影响因子
ACTA PHYSICO-CHIMICA SINICA
·
2026
·
IF 13.5
Yanyan Zhao,Jing Zhang,Xiaolong Li,Hailun Su,Lin Yang,Jianjun Zhang
A stable Py-HOF was prepared by employing H 4 TBAPy as precursor. • A TiO 2 /Py-HOF composite with excellent photocatalytic activity was constructed. • T/Py-HOF shows stability due to strong H-bonds and π–π interactions of H 4 TBAPy. • S-scheme charge transfer pathway was verified via ISI-XPS, fs-TAS, and DFT. • T/Py-HOF display good photocatalytic H 2 O 2 production yield and sterilization. Hydrogen-bonded organic frameworks (HOFs) hold substantial potential for application in photocatalysis. However, their practical application in photocatalytic H 2 O 2 generation and antibacterial activity remains hampered by intrinsically inefficient electron-hole separation and inadequate structural stability. Herein, a Py-HOF photocatalyst was prepared by employing 1,3,6,8-tetrakis (p-benzoic acid) pyrene (H 4 TBAPy) as precursor via self-assembly method, and the titanium dioxide/Hydrogen-bonded organic framework (TiO 2 /Py-HOF, T/Py-HOF) S-scheme heterojunction was rationally fabricated via an in-situ synthesis. Due to the strong hydrogen bonds and π–π interactions of H 4 TBAPy, the T/Py-HOF S-scheme heterojunction displays super stability. Furthermore, in-situ irradiated XPS, femtosecond transient absorption spectroscopy, and DFT calculations verify the S-scheme carrier migration mechanism within the T/Py-HOF heterojunction. Thanks to the ultrafast charge-transfer and excellent redox ability of the T/Py-HOF S-scheme photocatalyst, the optimally formulated T/Py-HOF-5% achieves a remarkable H 2 O 2 production rate of 1890 μmol g −1 h −1 , corresponding to approximately 15.24 and 6.19-fold enhancements compare to the pure TiO 2 and bare Py-HOF, respectively, along with excellent stability. Furthermore, the T/Py-HOF heterojunction also exhibits superior photocatalytic sterilization activity against Escherichia coli (E. coli) , achieving almost 100% of E. coli inactivation after 90 min light irradiation. Collectively, this work offers a novel insight for designing high-efficiency HOF-based S-scheme photocatalysts in energy and environment applications. A novel TiO 2 /Py-HOF S-scheme heterojunction was fabricated for efficient photocatalytic H 2 O 2 production and excellent photocatalytic E. coli sterilization. Download: Download high-res image (202KB) Download: Download full-size image
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2021
·
IF 6.609
Jun Zhang,Chengyu Li,Jing Gu,Haoran Yuan,Yong Chen
This study aimed to investigate the co-pyrolysis characteristics of strong-acid cation exchange resin (Amberlyst-15, denoted as A15) and cellulose (CE), in which the existing synergistic interaction effects were uncovered. Crucial variables including pyrolytic temperature, A15-to-CE mass ratio and heating rate were taken into consideration. The levoglucosenone (LGO) production from CE and inorganic sulfur-containing species release from functional sulfonic acid groups of A15 were enhanced in a temperature range of below 400 °C. In this regard, the LGO yield achieved approximately 7 wt% at 300 °C with A15-to-CE mass ratio of 1:1. Relatively, elevating the temperature and heating rate accelerated the A15 self-decomposition and small molecule fragments restructuring to give much more monocyclic and polycyclic aromatics. Noticeably, organic sulfur-containing compounds also were produced in an unignorable amount of 8.2% under preset conditions of pyrolytic temperature of 700 °C and heating rate of 20,000 °C/s. The plausible pathway for the co-pyrolysis transformation of A15 and CE was also proposed on the basis of experimental results. The present work will provide a probable and feasible strategy for the high-value utilization of biomass and waste ion-exchange resins, particularly in the aspect of the generation of certain chemicals.
研究领域:
能源与燃料
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环境科学
·
生物质转化
✓ 已验证
DOI
高影响因子
MICROCHEMICAL JOURNAL
·
2023
·
IF 4.8
Na Wang,An Gu,Guanghua Li,Yong Lei
Boiled tung oil is the commonly used drying oil in Chinese cultural relics, and light radiation, temperature are the important factors leading to its aging. In order to investigate the photo and thermal aging behavior of boiled tung oil and determine the characteristic parameters to evaluate its aging degree, micro-UV/Py-GC/MS system has been applied in the present work to monitor the volatile aging products released by boiled tung oil film, to obtain high aging degree boiled tung oil film in short time and to investigate its composition change in different aging degree. Research results showed that volatile products released by boiled tung oil film during UV irradiation and 60 ℃ were mainly series of aldehydes, ketones, carboxylic acids and hydrocarbons with small molecule. With increase of aging time, the type of volatile products remain unchanged, but their amount gradually decreases until cannot be detected. Pyrolytical products of unaged and aged boiled tung oil is the same, but with the increase of aging degree, relative content of glycerol, dicarboxylic acids and azelaic acid in boiled tung oil film gradually increased, while the relative content of oleic, linoleic and eleostearic acid, as well as the content ratio of mono-carboxylic acids to di-carboxylic acids gradually decreased. Changes of volatile and pyrolytical products during aging process were summarized to evaluate the aging degree of boiled tung oil used in cultural relics. Boiled tung oil used in two lacquerware samples collected from the same carved lacquer panel from Fuwang Ge in the Forbidden City, and two polychrome samples separately collected from the inner and outer eave of Yanxi Tang in the Forbidden City were investigated, the aging degree evaluation results of boiled tung oil in historical samples have further confirm the reliability of summarized parameters. Research results of the present work can provide scientific support for the conservation and restoration of related cultural relics, and also lay a foundation for the in-depth study of the photo and thermal aging mechanism of boiled tung oil.
研究领域:
文物保护
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分析化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
POLYHEDRON
·
2022
·
IF 2.975
Yan-Ling Deng,Wei Li,Chun-Yang Pan
Two new metal hybrid borates , Na[Ni(py) 2 ] 2 ·[(C 4 H 2 O 6 ) 2 B]·H 2 O (py = pyridine) ( 1 ) and [Cu(H 2 O) 2 (1-EI) 4 ]·[B 5 O 6 (OH) 4 ] 2 ·H 2 O (1-EI = 1-ethylimidazole) ( 2 ), have been successfully synthesized. 1 features an interesting structure based on mixed borate-tartrate motifs. Two tartrate anions are condensed with one BO 4 to form the hybrid anionic group [(C 4 H 2 O 6 ) 2 B] 5− . The structure of 2 is composed of [B 5 O 6 (OH) 4 ] − clusters and [Cu(H 2 O) 2 (1-EI) 4 ] 2+ complexes, which exhibits hydrogen-bonded network formed by [B 5 O 6 (OH) 4 ] − clusters. These compounds are further confirmed by FTIR, PXRD and UV–vis. In addition, the catalyst prepared from 2 shows excellent electrocatalytic oxygen reduction reaction (ORR) activity.
研究领域:
无机化学
·
电化学
✓ 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）