Catalysts
·
2022
·Vol. 12
·期 12
·1562
·
IF 4.501
Di Liu,Hui-Zi Huang,Zhejiaji Zhu,Jiani Li,Li-Wei Chen,Xiao-Ting Jing,An-Xiang Yin
The development and commercialization of direct ethanol fuel cells requires active and durable electro-catalysts towards the ethanol oxidation reactions (EOR). Rational composition and morphology control of Pt-based alloy nanocrystals can not only enhance their EOR reactivity but also reduce the consumption of precious Pt. Herein, PtCu nanocubes (NCs)/CB enclosed by well-defined (100) facets were prepared by solution synthesis, exhibiting much higher mass activity (4.96 A mgPt−1) than PtCu nanoparticles (NPs)/CB with irregular shapes (3.26 A mgPt−1) and commercial Pt/C (1.67 A mgPt−1). CO stripping and in situ Fourier transform infrared spectroscopy (FTIR) experiments indicate that the alloying of Cu enhanced the adsorption of ethanol, accelerated the subsequent oxidation of intermediate species, and increased the resistance to CO poisoning of PtCu NCs/CB, as compared with commercial Pt/C. Therefore, alloying Pt with earth-abundant Cu under rational composition and surface control can optimize its surface and electronic structures and represents a promising strategy to promote the performance of electro-catalysts while reduce the use of precious metals.Keywords:Pt–Cu alloy;nanocubes;electrocatalysis;ethanol oxidation reaction;in situ FTIR
研究领域:
材料科学
·
电化学
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DOI
高影响因子
MACROMOLECULES
·
2017
·
IF 5.835
Qingsong Lian,Yan Li,Kai Li,Jue Cheng,Junying Zhang
The vulcanization mechanism remains unclear due to the difficulty of characterization and the complexity of the vulcanization systems. In this work, a series of epoxy model systems were used to study the sulfur cleavage behavior, from which the study process of the vulcanization mechanism was significantly simplified and a brand new sulfur-only vulcanization mechanism was revealed by the FTIR and DSC analysis. Our studies suggest that thiyl radicals derived from the homolytic cleavage of sulfur play the dominant role in the vulcanization, while the heterolytic fission of sulfur cannot occur as expected because this reaction needs 200 °C. Nevertheless, sulfur anions, which are easy to be understood derived from the heterolytic cleavage of sulfur, are actually transformed from the thiol groups that are produced through the reaction of thiyl radicals abstracting α-H atoms of allyl groups in rubber, and this maybe the reason that vulcanization mechanism remains controversial for centuries.
研究领域:
材料科学
·
化学工程
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DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2016
·
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
·
热化学转化
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产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Li Zhou,Fashe Li,Wenchao Wang,Huicong Zhang,Yaozong Duan,Hua Wang
Phospholipids, as key trace constituents of biodiesel, can have complex effects on the performance of biodiesel. Exploring the mechanism of their influence on the pyrolysis and oxidation characteristics of biodiesel is crucial for controlling the generation and emission of pollutants. To this end, this study employed TG-FTIR-MS experimental technology and the ReaxFF-MD simulation method to investigate the effects of phosphatidylethanolamine (PE) on the activation energy ( E a ), gaseous product generation, and mechanism of Jatropha biodiesel pyrolysis and oxidation reactions. The results indicated that the addition of 400 ppm PE can reduce the pyrolysis E a of Jatropha biodiesel from 87.25 kJ/mol to 80.67 kJ/mol, consistent with simulated E a of 93.35 kJ/mol and 81.81 kJ/mol, respectively. This notably promoted the initial oxidation stage of the Jatropha biodiesel reaction, facilitating the generation of oxidation products such as CO and C 2 H 4 . In the pyrolysis reaction, PE promoted C 2 H 4 formation, primarily through reactions involving hydrocarbon small free radicals. In the oxidation reaction, the addition of PE increased the number and variety of active free radicals in the system, with the formation reactions of H 2 O and CH 2 O involving phosphorus-containing oxygen groups. Furthermore, a small amount of nitrogenous free radicals participates in the formation reactions of C 2 H 4 and CO.
研究领域:
能源科学
·
化学工程
·
环境科学
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DOI
高影响因子
JOURNAL OF CATALYSIS
·
2024
·
IF 6.5
Longyu Wang,Haibo Jin,Zhichang Liu,Suohe Yang,Guangxiang He,Haiyan Liu,Xianghai Meng,Chunming Xu
The formation mechanism and pathway of HMF from fructose dehydration were investigated using in-line FTIR monitoring and in-situ 13 C NMR in this study. The results of the infrared absorption spectrum obtained at different time intervals during the reaction process showed significant inconsistencies with the acyclic pathway. However, the in-situ NMR analysis revealed the direct observation of two intermediates, fructose furan and (4R-5R)-4-hydroxy-5-hydroxymethyl-4,5-dihydrofuran-2-formaldehyde, providing direct evidence to support the cyclic carbocation pathway. This study also included theoretical analysis of the intermediates involved in the key steps of various reaction pathways using density functional theory (DFT) calculations. The key steps in the cyclic pathway were found to have lower activation energy compared to the acyclic pathway, while exhibiting significant differences in electronegativity at the reaction sites. The computational results not only reveal but also provide support for the rationality of the cyclic formation mechanism. The response surface methodology (RSM) was utilized to optimize the preparation process of HMF through fructose dehydration. It enabled determination of the significance order for each factor (reaction temperature > reaction time > mass percentage of water in the solvent) and identification of the optimal process conditions (reaction time of 3.5 h, reaction temperature of 143.5 °C, mass percentage of water in the solvent of 5.0 %, and maximum yield of 5-HMF reaching 82.4 %).
研究领域:
化学工程
·
分析化学
·
计算化学
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产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY
·
2021
·Vol. 57
·期 1
·235-241
·
IF 3.713
Jinyue Zheng,Di Sun,Dengyong Liu,Jingxin Sun,Jun-Hua Shao
Summary The low-field nuclear magnetic resonance and Fourier transform infrared spectroscopy technique were carried out to evaluate the relationship between hydration characteristics and proteins structure in different stages pork of meat batters. The results showed that T 21 increased throughout the process and the change of T 22 and P 21 was easily impacted by water, and the alternation of secondary structure was mostly impacted by salt; P 21 was negatively correlated with the content of β -sheet ( r = −0.862), and positively correlated with the content of α -helix ( r = 0.933), β -turn ( r = 0.871) and random coil ( r = 0.677), which meant there was some relationship between secondary structure and water distribution and migration. This research will provide theoretical support for the processing and production of meat products.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Chenguang Zhang,Zilu Zhang,Chuancheng Dongye,Xiaofei Xu,Zhihe Li,Weiming Yi,Xiaobo Chen,Shaoqing Wang
Spent bleaching clay (SBC) and lignin wastes are generated from oil refining and paper industries, respectively. The complementary properties of these two types of waste enable synergistic effects in co-pyrolysis, thereby mitigating limitations characteristic of single-component pyrolysis. In this study, the co-pyrolysis behavior of the two wastes was explored at the microscopic molecular level using simultaneous TG-FTIR technology, coupled with fixed-bed pyrolysis experiments. The co-pyrolysis behavior was systematically investigated at the mass ratio of lignin and SBC (0 %L, 30 %L, 50 %L, 70 %L, and 100 %L) and different reaction temperatures (450, 500, 550, 600, and 650 °C). The results showed that the activation energy required for co-pyrolysis decreased at 50 %L and 70 %L ratios, as determined using FWO and KAS methods. The Ea required for co-pyrolysis decreased at 50 %L and 70 %L ratios. Specifically, the addition of 30 % SBC reduced the activation energy of lignin from 141.67 kJ/mol (KAS) and 146.41 kJ/mol (FWO) to 120.25 kJ/mol (KAS) and 126.04 kJ/mol (FWO), respectively. Furthermore, the 50 %L radio infrared absorbance of CH 4 and CO 2 was relatively strong due to the enhanced decarboxylation and demethoxylation reactions. Meanwhile, the fixed-bed co-pyrolysis experiment showed that the relative content of non-methoxy phenolics increased from 7.0 % to 10.6 % with bio-oil yield increasing from 27 % to 40 %, after adding 50 % SBC. Additionally, the interaction mechanism was proposed based on the TG-FTIR and fixed-bed pyrolysis experimental results. SBC served as a hydrogen donor to promote the thermal decomposition of lignin and improved the yields of phenol and alkylphenols. This work offers guidance for the synergistic conversion of renewable carbon sources with oily solid wastes.
研究领域:
环境科学与工程
·
能源化工
·
废弃物资源化
·
热化学转化
·
生物质能
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产品关联
DOI
高影响因子
Russian Journal of Physical Chemistry A
·
2017
·Vol. 91
·期 7
·1292-1300
·
IF 0.581
Zhang Binbin,Li Yantao,Hou Baorong
Ionic solvation in solutions of lithium tetrafluoroborate (LiBF 4 ) in propylene carbonate (PC) + dimethyl sulfoxide (DMSO) mixtures has been studied using Fourier transformed infrared (FTIR) spectroscopy. Dimerization of DMSO molecules in the solutions was taken into account. The obtained results are discussed with respect to the electrolyte concentration and properties of the cations of the electrolyte. Band changes due to solvation interaction were detected in the region of the C=O stretching vibrations and ring deformation for PC, and the S=O stretching vibrations and C–S–C skeleton stretching modes for DMSO, indicating that there is a strong interaction between lithium cations and solvent molecules. In addition, Li + was preferentially solvated by DMSO in these binary solvents as a result of the large difference in their donor number (DN) values. The structures of PC, DMSO, Li + -PC, Li + -DMSO, and Li + -PC+DMSO were given.
研究领域:
物理化学
·
电化学
·
光谱学
·
电池材料
·
溶液化学
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DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2026
·
IF 3.9
Zhu Jianxiang,Li Jiahui,Shen Runqiu,Song Yuwei,Xie Yuanyuan,Duan Hongliang,Su An
The development of efficient and sustainable amide-bond-forming
processes, together with their quantitative kinetic characterization,
is of major significance to the fine chemical and pharmaceutical industries.
In this study, the aminolysis of d -(−)-pantolactone
(DPL) with pyrrolidine (Pyr), catalyzed by 1,5,7-triazabicyclo[4.4.0]dec-5-ene
(TBD), was investigated in a continuous-flow microreactor equipped
with inline Fourier transform infrared (FTIR) spectroscopy. For the
first time, a flow-rate-ramp transient kinetic method was applied
to an organobase-catalyzed aminolysis system. A multiresponse FTIR–PLS
quantitative model was developed using Latin hypercube sampling (LHS)
for calibration-set design, thereby effectively reducing the collinearity
inherent in conventional calibration samples distributed along the
reaction stoichiometric line. An analytical mapping between experimental
time and the actual residence time of fluid elements under dynamic
flow conditions was established, making it possible to extract continuous
kinetic data over a residence-time range of 2–40 min from just
one 83.1 min flow-rate-ramp experiment. The reaction orders with respect
to DPL, Pyr, and TBD were determined to be 1, 1, and 0.85, respectively,
via the isolation and initial-rate methods. An explicit analytical
expression for DPL conversion was derived based on a plug-flow reactor
model. Arrhenius analysis yielded an activation energy of 26.26 kJ·mol –1 and a pre-exponential factor of 2.96 × 10 5 L 1.85 ·mol –1.85 ·min –1 . The resulting model demonstrated good predictive
accuracy when applied to temperatures and initial concentrations outside
the fitting range. This work provides a reliable kinetic basis for
the design and scale-up of continuous DPL aminolysis processes and
offers a rapid and resource-efficient strategy for kinetically characterizing
related metal-free organocatalytic systems.
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DOI
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2015
·
IF 2.912
Xianghe Meng,Lei Li,Qin Ye,Frederik van de Voort
A primary Fourier transform infrared (FTIR) method capable of determining acidity in ester-based oils is described and evaluated. Absolute free fatty acid (%FFA) and acid value (AV) calibrations were devised by spiking oleic acid into a refined, acid-free oil and measuring νCOO– at ∼1569 and νphenolate– at ∼1588 cm–1, respectively, in the second-derivative differential spectra. The FTIR acidity predictions were compared to the AOCS titrimetric method using acid mixtures as well as acid containing used vendor oils of undefined makeup and provenance, using two spectroscopically divergent reference oils as AC0. Relative to the AOCS reference method, the FTIR procedure was found to be both more accurate (±0.107 vs ±0.122) and reproducible (±0.025 vs ± 0.077) in determining %FFA and similar in predicting AV. The FTIRphenolate method overcomes a variety of limitations of earlier FTIR-based methods, being particularly simple and well suited to routine, semiautomated acidity analysis of ester-based oils using a basic FTIR spectrometer.
研究领域:
分析化学
·
食品科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2017
·Vol. 409
·期 10
·2531-2537
·
IF 3.431
Cheng Hao,Wu Shubin,Huang Jinbao,Zhang Xiaohua
Although o -quinonemethide (6-methylene-2,4-cyclohexadien-1-one) has been proposed as a key intermediate in char formation during the pyrolysis of guaiacol (2-methoxyphenol), direct evidence of this (e.g., spectroscopic data) has not yet been provided. Using in situ FTIR spectroscopy, the pyrolysis of guaiacol was investigated from 30 °C to 630 °C at 40 °C/min. The IR profiles showed direct evidence of o -quinonemethide production at about 350 °C, which vanished rapidly at around 420 °C in the vapor phase, indicating char formation. In addition, at 400 °C, salicyl aldehyde was observed, which decomposed slowly at about 500 °C. In combination with the known products of guaiacol pyrolysis, these results allowed the major reaction pathways of guaiacol pyrolysis to be discerned. Density functional theory calculations were performed, and the results were found to be in good agreement with the experimentally obtained IR profiles. These findings provide guidance on how to suppress secondary reactions of guaiacol during lignin pyrolysis.
On-line analysis of pyrolysis process of guaiacol using in situ FTIR
研究领域:
化学
·
材料科学
·
能源科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
BIOMASS & BIOENERGY
·
2022
·
IF 5.774
Beier Jiang,Yuanyuan Ma,Lijing Wang,Zhou Guo,Xinyu Zhong,Tongtong Wu,Yuanyuan Liu,Haigang Wu
Molecular structure of hyperbranched polyglycerols (hbPGs) strongly affected the thermal stability as the critical heat transfer medium to maintain thermal homeostasis during working of heat engine. Here, thermogravimetric analysis (TGA)-fourier-transform infrared spectroscopy (FTIR)-gas chromatography (GC)-mass spectroscopy (MS) and reactive force-field (ReaxFF) techniques were utilized to identify major thermal decomposition products and explore the molecular mechanism. TGA-FTIR-GC/MS results showed that the major products were CO, CO 2 , water molecules and C3 organic moieties. To perform ReaxFF molecular dynamic simulation, timestep-dependent images revealed that C3 molecules were mainly originated from glycerol units and hydroxyl groups played an essential role in catalyzing thermal decomposition. To examine our hypothesis, different methoxylation levels of hbPGs were prepared, and TGA analysis of these methoxylated hbPGs polymers clearly corroborated that lower percentage of hydroxyl groups in the hbPGs can significantly increase maximum peak temperature from ∼400 °C to ∼460 °C. Our investigation clearly provided the molecular mechanism of hbPGs thermal decomposition and identified a potential way to improve thermal stability of hbPGs.
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产品关联
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高影响因子
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