ACS Catalysis
·
2025
·
IF 13.1
Tao Wang,Qiao Yu,Zhilin Chen,Chao Xiao,Shuming Peng
The active phase for methane combustion is still in debate. Low-temperature CO-FTIR spectroscopy was used to probe the working surface state on a series of Pd/Al2O3 (PdAl) and Pd/silicalite-1 (PdSil) catalysts with different starting states: oxidized, reduced (R), reoxidized (Ro). The surface of prereduced PdAl (Pd0) is transformed to an oxidized state (PdOx) with a CO stretching vibration (νCO) at ∼2157 cm–1 when it is aged in the methane oxidation mixture. The aging-induced transformation from Pd0 to PdOx occurred at 250 °C or above. Although PdSil has multiple kinds of PdOx entities, prereduced PdSil also transformed into PdOx. For PdAl(4)-R-A250, XRD patterns suggest weak bulk oxidation of Pd0 at 250 °C, XPS spectra indicate 28% of surface Pd0 atoms are oxidized, but CO-FTIR spectra confirm all the “top surface” Pd0 atoms are oxidized. It demonstrates the advantage of CO-FTIR spectroscopy in probing the top surface state. Finally, a direct correlation between operando FTIR spectroscopy and low-temperature CO-FTIR spectroscopy was established. Operando FTIR spectra over PdSil during methane oxidation at 250 °C gives two bands at 2124 cm–1 (CO–Pd+) and 2161 cm–1 (CO–Pd2+). After cooling in nitrogen, CO-FTIR spectra give two similar bands at 2134 cm–1 and 2157 cm–1. The “working surface state” can be preserved in CO-FTIR. For PdAl(4), operando FTIR spectra at 250 and 300 °C give no bands of adsorbed CO. Adding CO into the methane oxidation mixture resulted in a single CO–Pd2+ band at 2163 cm–1, which is in accord with their CO-FTIR spectra. For operando FTIR spectroscopy, the observation of the bands of adsorbed CO depends on the accumulation of the CO intermediates, but their accumulation is limited to reaction temperatures below 300 °C and to PdSil (not PdAl). These limitations make low-temperature CO-FTIR spectroscopy more general and sensitive.
研究领域:
催化化学
·
材料科学
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环境化学
·
光谱学
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Analytical Chemistry
·
2015
·
IF 1
Nai-Dong Chen,Nai-Fu Chen,Jun Li,Cai-Yun Cao,Jin-Mei Wang,He-Ping Huang
GC-MS method combined with FTIR techniques by the analysis of polysaccharide was applied to evaluate the similarity between wild (W) and tissue-cultured (TC) Dendrobium huoshanense (DHS), Dendrobium officinale (DO), and Dendrobium moniliforme (DM) as well as 3 wild Dendrobium spp.: Dendrobium henanense (DHN), Dendrobium loddigesii (DL), and Dendrobium crepidatum (DC). Eight monosaccharides involving xylose, arabinose, rhamnose, glucose, mannose, fructose, galactose, and galacturonic acid were identified in the polysaccharide from each Dendrobium sample while the contents of the monosugars varied remarkably across origins and species. Further similarity evaluation based on GC-MS data showed that the values of different origins of DHS, DO, and DM were 0.831, 0.865, and 0.884, respectively, while the values ranged from 0.475 to 0.837 across species. FTIR files of the polysaccharides revealed that the similarity coefficients between W and TC-DHS, DO, and DM were 88.7%, 86.8%, and 88.5%, respectively, in contrast to the similarity coefficients varying from 57.4% to 82.6% across species. These results suggested that the structures of polysaccharides between different origins of the investigated Dendrobiums might be higher than what we had supposed.
研究领域:
植物化学
·
药用植物学
✓ 已验证
DOI
PubMed
高影响因子
Pigment & Resin Technology
·
2025
·
IF 1.5
Raouf Mahmood Raouf,Ahmed A. Ayash
Purpose The purpose is to investigate the effect of Indium oxide nanoparticles on thermoset epoxy. In more details, the filler used is pure Indium oxide nanoparticles (50 nm) and Fourier transform infrared spectroscopy analysis (FTIR) analyses has been done to understand the structural changes on epoxy network. Also, the effect of Indium oxide on the epoxy matrix is explored comprehensively to encompass the thermal, electrical and mechanical properties. Accordingly, a series of experiments have been conducted and are presented in the next section. Design/methodology/approach In all the experiments, the polymerisation of epoxy was carried out under constant pressure (1 atm) and temperature (30 °C) using a water bath. The monomers of epoxy were mixed according to the stoichiometric ratio recommended by providing Company to ensure getting the optimum properties after curing the samples. To create a mixture, three concentrations (1%, 3% and 5%, w/w) of the indium oxide nanoparticles In2O3 NP were manually added to the polymer solution. After that, the samples were dried for 4 h at 40 °C in a drying oven and then they are post-cured for 24 h at ambient temperature. Findings Interestingly, the FTIR spectra showed that there are aromatic rings in the nanocomposites structure which might be responsible for the notable increase in mechanical strength and thermal stability. Further, an enhancement in electrical properties has been observed. In general, the results are promising and might open up many applications of such system (i.e. Indium oxide/epoxy) in many areas such as conductive coatings, electrical and electronic gadgets, alternative energy……….etc. Originality/value While there are many studies used different types of metal-oxide fillers to produce epoxy nanocomposite, a little amount of work has been reported on indium oxide in the last decade. Most the reported studies are limited to exploring the impact of Indium tin oxide nanopowders on the composite’s electrical and optical properties. Here, the work is different than these studies. The filler used is pure Indium oxide nanoparticles (50 nm) and FTIR analyses has been done. Further, the effect of Indium oxide on the epoxy matrix is explored comprehensively, for the first time, to encompass the thermal, electrical and mechanical properties.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2022
·Vol. 14
·期 15
·3158
·
IF 4.967
Chunxia Zhu,Shuyu Pang,Zhaoxia Chen,Lehua Bi,Shuangfei Wang,Chen Liang,Chengrong Qin
At present, the synthesis methods of crystalline porous materials often involve powder products, which not only affects the practical application but also has complex synthesis operations and limited scale. Based on the mechanochemical method, we choose COF-TpPa-1, preparing TpPa-1-DANC composites. Covalent organic frameworks (COFs) are a kind of crystalline material formed by covalent bonds of light elements. COFs possess well pore structure and high thermal stability. However, the state of synthesized powders limits their application. Cellulose nanocrystals (CNCs) are promising renewable micron materials with abundant hydroxyl groups on their surface. It is possible to prepare high-strength materials such as film, water, and aerogel. Firstly, the nanocellulose was oxidized by the sodium periodate method to obtain aldehyde cellulose nanocrystals (DANC). TpPa-1-DANC not only had the crystal characteristic peak of COFs at 2θ ≈ 5° but also had a BET surface area of 247 m2/g. The chemical bonds between COFs and DANC formed by Schiff base reaction appeared in FTIR and XPS. The pyrolysis behavior of the composite was characterized by TG-IR, which showed that the composite had good thermal stability. With the advantages of nanocellulose as a material in every dimension, we believe that this method can be conducive to the large-scale synthesis of COFs composites, and has the possibility of multi-form synthesis of COFs.Keywords:covalent organic frameworks;aldehyde cellulose nanocrystals;mechanochemistry;TGA/FTIR
研究领域:
材料科学
·
化学工程
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
THERMOCHIMICA ACTA
·
2017
·
IF 2.236
Jing Liu,Rujuan Li,Mengya Guo,Hairong Tao,Donglan Sun,Chengxing Zong,Chunjing Liu,Fengzhi Fu
We recently found that the introduction of benzene ring as connection block improved the thermal stability of glycerol carbonate derivatives. To further explore how polysubstitution on benzene influences their thermal stability, another two derivatives, benzene-1,3,5-tricarboxylic acid tris-(2-oxo-[1,3]dioxolan-4-ylmethyl) ester (BATE1) and benzene-1,2,4,5-tetracarboxylic acid tetrakis-(2-oxo-[1,3]dioxolan-4-ylmethyl) ester (BATE2), were synthesized and characterized by a combined TG–FTIR and theoretical calculation. TG results showed that both BATE1 and BATE2 had three weight loss stages. FTIR spectra of evolved gases and the bond dissociation energy for the two compounds indicated that during the pyrolysis process, the C C, C O bonds of five-membered cyclic carbonate fractured preferentially to produce volatile carbonates and CO 2 , and then the nearby C O bond of esters continued to crack to produce more fragments. Finally, benzene ring still remains in the solid pyrolysis products. Therefore, improving the thermal stability of compound cannot be achieved simply by increasing the number of substituents on the benzene ring.
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2018
·Vol. 132
·期 3
·1729-1740
·
IF 2.209
Yuan Jiao-jiao,Tu Jun-ling,Xu Yong-jun,Qin Frank G. F.,Li Bing,Wang Cheng-zhang
Olive leaf extract pretreated by enzymolysis was selected for studying the thermal stability at different heating rates by thermogravimetric coupled with infrared spectroscopy (TG–FTIR) and nonisothermal theoretical analysis, and products analysis by pyrolysis–gas chromatography–mass spectrometry (Py–GC–MS). Results revealed that thermal decomposition of ethyl acetate extract from olive leaf extract pretreated by enzymolysis (EAEEH) consisted of two steps and had a lower thermal stability. The nonisothermal decomposition kinetics mechanism of EAEEH was D3 model (three-dimensional diffusion, Jander equation, the first step) and F3 model (chemical reaction, n = 3, the second step). TG–IR showed –CH 3 , –C=C–, –OH, –C–O were continuously accelerated to produce, and evolved gas were CO 2 , water, CO and CH 4 at the end. In addition, it was found that there were mainly polyphenols with phenolic hydroxyl groups in the pyrolysis products by Py–GC–MS, and it was also explained for the thermal stability results. This will provide a theoretical guidance for thermal application of EAEEH in the safe natural food additives, cosmetic and medicine.
研究领域:
食品科学
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化学工程
·
植物化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2022
·
IF 6.437
Jianwei Zhang,Ling Chen,Liangyou Zhao,Guorui Jin,Weidong He
Nitrogen heterocycles as Nitrogen-rich energetic material has been widely popularized due to their desirable properties like low sensitivities, excellent stability, and lower environmental impact, less erosive and less toxic combustion gases , especially in gun propellant application areas. The focus of this study is on investigating interaction mechanism of 1 H-tetrazole (1 H-TZ) and nitrocellulose (NC) by kinetics methods and TG-DSC-FTIR analysis. The mixture (NC-TZ) between 1 H-TZ and NC was prepared by means of physical blending. DSC experiments indicated that the open and closed environment can generate different and important influence on the chemical reaction between 1 H-TZ and NC. Combined with the change of activation energy , it illustrated that the gas 2 H-tetrazole, the isomer of 1 H-TZ, had a significant influence on the thermal decomposition of NC. In comparison with kinetic models of NC and NC-TZ, it can be found that the addition of 1 H-TZ mainly affected the contribution factor and m value in the first stage. The value of m decreased from 1.00 to 0.15, meanwhile, the contribution factor was decreased from 0.50 to 0.12. It showed that NO 2 , the initial decomposition product of NC, had taken part in the thermal decomposition process of 1 H-TZ. TG-DSC-FTIR experiments indicated that there was a chemical reaction between 2 H-tetrazole and the initial decomposition product of NC, NO 2 , to form CO, N 2 O and HN 3 .
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Zhanshi Ni,Zhihui Song,Haobo Bi,Chunlong Jiang,Hao Sun,Zhicong Qiu,Liqun He,Qizhao Lin
Facing the severe environmental and energy crisis, how to use solid waste cleanly and efficiently is imminent. In this study, coal slime and cellulose are used for co-combustion experiments. Coal slime and cellulose are tested at mass ratios of 10:0, 9:1, 7:3, 5:5, 3:7, 1:9, and 0:10. When 10 % cellulose is added to the coal slime, the ignition temperature decreases by 169.3 °C, and the ignition characteristic index increased by 2.9 times. The addition of cellulose makes the comprehensive combustion performance of the sample increase exponentially. By analyzing the dominant reaction in the co-combustion process of coal slime and cellulose, the variance contribution rates of the first principal component and the second principal component are 67.84 and 29.18 %, respectively. Co-combustion of coal slime and cellulose enhances the release and combustion of early volatiles. In addition, the evolution law of gaseous products and the temperature dependence of gaseous products in the co-combustion process of coal slime and cellulose are analyzed by fourier transform infrared spectroscopy and two-dimensional correlation spectroscopy, respectively. This study provides a theoretical basis for the large-scale application of co-combustion of coal slime and biomass.
研究领域:
能源与环境科学
·
燃烧化学
✓ 已验证
DOI
高影响因子
CHEMOMETRICS AND INTELLIGENT LABORATORY SYSTEMS
·
2025
·
IF 3.8
Zeyu Hou,Bingxin Yan,Yuhan Zhao,Shengbo Zhang,Bo Su,Kai Li,Cunlin Zhang
Artificial sweeteners, as a type of food additive, have vibration frequencies mostly concentrated in the terahertz (THz) band, which enables us to utilize THz technology to deeply analyze their molecular properties. To gain a more comprehensive understanding of the features of artificial sweeteners, this study specifically chose aspartame and acesulfame as representatives. Initially, we employed PXRD and Raman spectroscopy techniques to carry out a thorough examination and verification of the crystalline structure as well as the purity levels of these two synthetic sweeteners. Then, with the aid of Fourier transform infrared spectroscopy (FTIR) technology and terahertz time-domain spectroscopy (THz-TDS) system, the spectral characteristics of aspartame and acesulfame were precisely measured. Moreover, the crystal configurations of these two artificial sweeteners were simulated using solid-state density functional theory (DFT), and the simulation results were in good agreement with the experimental results, further validating the effectiveness of our research methods. Finally, using microfluidic chip technology, the THz spectral characteristics of aspartame and acesulfame in solution were determined, and were compared with their spectra in solid state. We found that the THz spectra of the two artificial sweeteners in solid and solution states have significant correlations. In addition, the research further elucidated that the THz spectrum of a substance dissolved in a solution exhibits a close correlation with its concentration within that solution. These findings provide new perspectives and value for our in-depth research on artificial sweeteners.
研究领域:
食品科学
·
分子光谱学
·
计算化学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE CHEMICAL LETTERS
·
2018
·
IF 2.631
Rongqiao Chen,Chune Guo,Wubo Chu,Nan Jiang,He Li
Marine microorganism accumulated on the surface of ships or pipelines would accelerate fouling organisms, such as mussels and barnacles, adhered on the surface. It was significant to understand the bio-interaction between the microorganisms and the surface. Attenuated total reflection (ATR) Fourier transform infrared (FTIR) spectroscopy was used to study the initial stages of marine microorganism adhering to surfaces, because it could probe the microorganism interaction to the surface regardless of the water interference. Bacillus sp. and Escherichia coli were selected to study the initial attachment on different surfaces, because they were typical fouling microorganisms and showed opposite Gram stain results. The assays were conducted respectively in dried and settled bacteria on two different surfaces (ZnSe, Al 2 O 3 coated on ZnSe). IR spectra of settled bacteria showed amide I band red shift and amide II band blue shift in aqueous environment on both surfaces compared with the dry bacteria. The reasons of amide bands shift were investigated and it was discovered that the hydrogen bond between the water and the protein of the bacteria led to the protein secondary structure change. ATR-FTIR provided an approach to study the attachment process and showed dynamic changing process on the surface, and it could be an appropriate approach to study the interaction between proteins and chemicals.
研究领域:
微生物学
·
生物化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2021
·Vol. 28
·期 7
·1-11
·
IF 3.097
Yu Xueyi,Fang Zeming,Qin Yijing,Lu Dong,Liu Qianfa,Luo Li,Lin Zhiyong,Wang Ke
Thermosetting Polyphenylene oxide (PPO)/Triallyl isocyanurate (TAIC) based composite systems have attracted considerable attentions in recent years due to their excellent performance as the substrate for printed circuit boards (PCBs) used for 5G networks. Since the residuals of -OH and -C = C- groups have significant effects on the properties of the substrate, especially the dielectric properties and thermal stability, it is critical to establish valid methods for characterizing these systems. In this work, FTIR, 1 H-NMR and 13 C-SSNMR were employed to qualitatively and quantitatively characterize the -OH and -C = C- groups in the methyl methacrylate (MMA) terminated PPO/TAIC co-cured system. No -OH groups were detected on the molecular chains of PPO oligomers, indicating that almost all the phenolic hydroxyl groups in the precursor had been substituted. During the curing, no new -OH groups were generated but some -C = C- groups were left unreacted. FTIR quantitative analysis showed that these -C = C- groups belonged to TAIC and the residual ratio of -C = C- could be as high as 60.37%.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry C
·
2024
·
IF 3.3
Tao Wang,Benlong Yu,Long Mu,Zhilin Chen,Chao Xiao,Shuming Peng
The palladium oxide phase (PdOx) plays a critical role in catalytic methane oxidation and CO oxidation reactions. Precise characterization of supported PdOx by CO-FTIR spectroscopy is often accompanied by the reduction of PdOx by CO. Lowering the CO partial pressure to 0.05% CO/N2 (0.5 mbar) and the adsorption temperature to −130 °C is a proper condition to inhibit the reduction completely. Then CO-FTIR spectroscopy was conducted on a series of supported PdOx catalysts. We find that CO adsorbed on coordinatively unsaturated Pd atoms (Pdcus) on the PdOx surface gives three adsorption bands at ∼2145 cm–1. Three types of surface Pdcus atoms with different degrees of coordination unsaturation (types I, II, and III) exist in supported PdOx catalysts; their νCO are located at 2133, 2145, and 2160 cm–1, respectively. The order of coordination unsaturation of surface Pdcus should be type III < type II < type I. Since νCO of surface Pdcus is between νCO of Pd2+(CO) and Pd+(CO), the effective charge of surface Pdcus is 1 < n < 2. For small PdOx clusters in zeolite-supported PdOx catalysts, surface Pdcus atoms with more coordination unsaturation (i.e., step, edge, and corner sites) are more abundant, leading to greater IR intensity of adsorbed CO.
研究领域:
催化化学
·
表面化学
·
光谱学
·
材料科学
·
环境化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）