Energy Science & Engineering
·
2019
·Vol. 7
·期 5
·2237-2246
·
IF 2.893
Yuan Zhao,Hao Xu,Kaifeng Lu,Yang Qu,Lingjun Zhu,Shurong Wang
In this study, the most abundant C5 carbohydrate unit in biomass, namely xylose, was chosen as the feedstock, and its hydrothermal conversion for furfural production was carried out in a green and renewable solvent system composed of water and butanone, in order to study the role of FeCl 3 and [bmim]Cl of ionic liquid catalyst in the conversion process of xylose. A key intermediate named xylulose from Lewis acid-catalyzed xylose isomerization was quantified. It was concluded that appropriate content of FeCl 3 and [bmim]Cl favored the isomerization-dehydration reaction path along which xylose was converted into furfural, while excessive amount of either component would result in side reactions leading to furfural consumption at long reaction times. By comparison between ionic liquid catalysts that had different active metal sites, xylose conversion and furfural yields were found to increase when the Lewis acidity of the metal ions became stronger. Moreover, chlorometallate anions with better catalytic performance than the original neutral salts were formed during catalyst preparation, and in this way, the xylose conversion and furfural formation were further promoted. Finally, the optimized ionic liquid catalyst produced a highest furfural yield of 75% and xylose conversion of 99% at 140°C.
研究领域:
生物化学
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可再生能源
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Li Xia,Wenxi Zhou,Yifan Xu,Zhengqiang Xia,Xinzhi Wang,Qi Yang,Gang Xie,Sanping Chen,Shengli Gao
The introduction of rich-electron ligands is a promising strategy to improve the ligand-to-metal charge transfer (LMCT) ability of metal–organic frameworks (MOFs) for efficient photocatalytic CO 2 reduction reactions (CO 2 RR), while the resulting impaired Lewis acid sites go against stable bonding with CO 2 and hinder the electron transfering to CO 2 . It is thus the key to search a trade-off between increasing LMCT and frustrating Lewis acid. Herein, the ferrocene (Fc) modified UiO-66 series MOFs, NH 2 -UiO-66-Fc, have been prepared to optimize LMCT for boosting CO 2 RR through a simple solvent-assisted ligand incorporation (SALI) method. Theoretical calculation and systematic experiments, including photoelectrochemical measures, in situ electron paramagnetic resonance, fluorescence probe analysis and X-ray photoelectron spectroscopy indicate that with increasing Fc content, the LMCT energy of MOFs significantly decreases from 2.66 to 2.10 eV based on the established electron transfer double-channel mechanism, while the Lewis acidity of Zr sites reduces with the CO 2 adsorption energy ( E ad ) ranging from −1.061 to −0.632 eV. Through introducing an optimal Fc content, NH 2 -UiO-66-Fc (2.0) integrating satisfactory LMCT ability and Lewis acidity shows superior photocatalytic CO 2 RR performance (CO yield: 90.65 μmol·g −1 ·h −1 ), about 13 times higher than that of the unmodified MOF and superior to most reported pristine MOF photocatalysts. DFT calculation demonstrates that the excellent performance of NH 2 -UiO-66-Fc (2.0) is attributed to the lowest energy barrier of 1.50 eV for the rate-limiting step of *COOH formation. In this work, such a simple post-modification strategy for facilitating the whole electron transfer path of photocatalytic CO 2 RR will provide a new way to construct high-performance MOFs-based CO 2 RR photocatalysts.
研究领域:
材料科学
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环境科学
·
化学
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DOI
高影响因子
MOLECULES
·
2025
·Vol. 30
·期 7
·1457
·
IF 4.6
Fenfen Guo,Yuxuan Wang,Zhicheng Jiang,Youjing Tu,Ruikai Li,Xingyu Zhang,Aoyi Tang,Yuan Liang,Lishi Yan,Hu Luo,Shenggang Li,Lingzhao Kong
The catalytic production of lactic acid from carbohydrates was considered a green way to efficiently utilize renewable biomass resources. In this study, an easy post-synthesis method was used to prepare a Sn-Beta catalyst for the production of lactic acid from glucose at 180 °C, 2 MPa, and 30 min. With optimized reaction time, temperature, pressure, and the ratio of raw material to catalyst, the yield of lactic acid reached an astonishingly high level of 76.0%. In addition, the catalyst characterizations were performed in-depth, revealing the intrinsic relationship between catalyst performance and structure, proving that the 2 wt% Sn was uniformly dispersed in the skeleton of Beta zeolite, which significantly increased the density of Lewis acid. Thus, the enhanced isomerization and retro-aldol condensation processes over the Lewis acid sites led to the high yield of lactic acid. This catalytic system kept stable after five cycles at mild conditions, showing high potential for industrial biomass utilization.
研究领域:
生物化学
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催化化学
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产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2021
·
IF 19.503
Guangyao Zhai,Yuanyuan Liu,Yuyin Mao,Honggang Zhang,Lingtong Lin,Yujie Li,Zeyan Wang,Hefeng Cheng,Peng Wang,Zhaoke Zheng,Ying Dai,Baibiao Huang
CO 2 cycloaddition reaction from propylene oxide and CO 2 to cyclic carbonates is a desirable process to become carbon neutral. Photo energy can decrease the temperature and pressure needed for this reaction according to our previous results. However, the relationship between Lewis acidity and the photophysical process needs to be clarified and optimized. Hence, in this work, Zn is introduced into UiO-bpydc via the coordination of Zn with the bipyridyl group in bpydc. It is found that the introduction of Zn not only effectively activate propylene oxide, but also promote ligand to metal charge transfer (LMCT) process, which ultimately is beneficial for CO 2 activation. However, Ce plays a negative effect under light irradiation. namely, the presence of Ce facilitates the energy transfer process rather than the LMCT process.
研究领域:
材料科学
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催化化学
·
光催化
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DOI
高影响因子
DALTON TRANSACTIONS
·
2024
·
IF 3.5
Zhengyan Wang,Chenhao Yuan,Dong Yang,Mifen Cui,Jihai Tang,Zhuxiu Zhang,Xu Qiao
It is of great significance to develop catalysts for the degradation of hexachlorobenzene from the industrial thermal process. In this paper, formic acid was used as a modulator to generate defect sites in Ce/Zr-UiO-66 with intrinsic Brønsted acidity. The defective formate ligands were removed through methanol–water vapor treatment to expose additional open metal sites with Lewis acidity. The intrinsic Brønsted acid sites of the resulting Ce/Zr-UiO-66-FA-P achieved a hexachlorobenzene degradation efficiency of 99.5% at 250 °C. The generated Lewis acid sites facilitated the C–C cleavage of degradation intermediates. More than 95.0% of the final products were CO2/CO, coupled with chlorinated alkanes/alkenes, which outperformed other benchmark metal oxide catalysts. The Ce/Zr-UiO-66-FA-P catalyst maintained its catalytic activity in the model industrial flue gas and humid environment. The degradation pathway of hexachlorobenzene was tracked using in situ FT-IR spectra.
研究领域:
环境科学
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催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2016
·
IF 3.349
Xing Chu,Dan Zhou,Dan Li,Kun Xia,Ning Gan,Xinhuan Lu,Renfeng Nie,Qinghua Xia
This work has firstly constructed purely Lewis acidic sites on MCM-41 successfully, for which Zr-MCM-41 catalysts with different Zr contents are prepared through the hydrolysis of ZrOCl 2 on MCM-41, followed by calcination . Thus-prepared materials possess typical hexagonal mesostructures, irregular morphologies, large surface areas, and large pore sizes, as revealed by XRD , SEM, TEM, N 2 adsorption, and DRIFT FTIR. UV–vis, Raman and XPS spectra prove the formation of isolated species in high dispersion on the surface of MCM-41. NH 3 -TPD analysis shows that the acid intensity of the catalysts is proportional to the content of Zr, and the acidity of Zr-MCM-41 with the Zr content of <0.5% is very weak. Pyridine-IR spectra show that the surface acidity is mainly consisted of Lewis acidity, and solely Lewis acidic sites are constructed on Zr-MCM-41(550) with a low Zr content < 0.5 wt%. More Lewis acidic sites exposed on the surface of Zr-MCM-41 are considerably important for promoting the titled Prins condensation.
研究领域:
催化化学
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材料科学
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产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2019
·
IF 14.229
Munir Ahmad,Xie Quan,Shuo Chen,Hongtao Yu
Iron containing MOFs have been currently estimated as greater candidates for heterogeneous Fenton catalysts due to their open pores and well dispersed metallic components. However, metals in majority of MOFs are bounded by organic linkers, which reduces Lewis acid sites and make them not available for H 2 O 2 activation. Creating coordinatively unsaturated metal centers (CUCs), acting as Lewis acid sites, is a feasible approach for efficient photo-Fenton activity. Here, we successfully synthesized a photo-Fenton CUCs-MIL-88B-Fe catalyst with mixed-valence (Fe II /Fe III ) on ultrathin Ti 3 C 2 nanosheets. The Lewis acidity was probed by TPD-NH 3 and IR-pyridine analysis and tested for pollutants degradation. The results showed that CUCs-MIL-88B-Fe/Ti 3 C 2 displayed highest photo-Fenton activity under visible light irradiation at pH 3.0 and 10 mM H 2 O 2 . This could be attributed with the CUCs, fast H 2 O 2 activation, high Lewis acidity and carrier separation with Ti 3 C 2 nanosheets due to its high charge mobility. Furthermore, CUCs-MIL-88B-Fe/Ti 3 C 2 exhibited a good stability and reusability.
研究领域:
材料科学
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环境科学
·
化学工程
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产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2023
·
IF 4.2
Ziqi Ren,Lu Fang,Miao Cui,Tianming Lv,Huifang Wu,Ziyi Feng,Zhaochi Feng,Changgong Meng,Limin Ren
Catalyst engineering plays a key role in bridging gaps between the structure of the Lewis acid center and its corresponding catalytic performance. In this regard, work that has been done in tuning active sites of Hf-containing zeolites, which hold promising catalytic activity for a variety of hydrogen-shift reactions, is far from complete. Herein, a Hf-B-BEA catalyst was rapidly prepared (within hours) by a hydrothermal semi-reconstruction strategy, involving partial framework etching of parent B-BEA and Hf grafting during the reassembling process. Then, an acid treatment was performed for expelling the boron atoms from the framework; more importantly, Hf migration into the silanol nests was triggered. The acid treatment worked powerfully as the driving force for transforming the semi-framework Hf into well-defined tetrahedrally coordinated framework Hf, thus endowing Lewis acidity of the obtained Hf-BEA. Consequently, this operation greatly boosted the Meerwein–Ponndorf–Verley reduction performance of Hf-BEA, which was almost inactive over the pristine Hf-B-BEA. The rational regulation of Hf sites provides new concepts in designing Hf-containing zeolites and understanding the structural–activity relationship.
研究领域:
催化化学
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材料科学
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产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2019
·Vol. 43
·期 20
·7725-7732
·
IF 3.069
Yun Hao,Ying-juan Hao,Jie Ren,Biao Wu,Xiao-jing Wang,Dishun Zhao,Fa-tang Li
In this work, N-methyl-2-pyrrolidonium (NMP) was acidized using hydrochloric acid to obtain [Hnmp]Cl first, which was then reacted with FeCl3 to prepare a series of inexpensive tunable [Hnmp]Cl·xFeCl3 (x = 0.2–2.0) ionic liquids (ILs) for the extractive and oxidative desulfurization of model oils. The Lewis acidities of these ILs were tested by the Fourier transform infrared (FT-IR) method, which indicated that when the x value of [Hnmp]Cl·xFeCl3 was above 1.0, the ILs exhibited Lewis acidity. The extraction results showed that the acidification of NMP reduced its dissolubility ability toward dibenzothiophene (DBT) and its Lewis acidity played a determining role in extractive desulfurization. In the catalytic oxidation removal process of the DBT model oil in the presence of H2O2, electron paramagnetic resonance (EPR) and scavenger experiments showed that the hydroxyl radical (˙OH) plays a key role and the superoxide anion radical (O2˙−) has a minor function. [Hnmp]Cl·1.5FeCl3 IL showed excellent recycling performance, which was due to its high dissolving capacity (23 700 ppm) for dibenzothiophene-sulfone (DBTO2).
研究领域:
化学工程
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环境科学
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产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Bo Tang,Shuang Li,Wei-Chao Song,En-Cui Yang,Xiao-Jun Zhao,Naijia Guan,Landong Li
In this work, BEA-type hierarchically structured stannosilicate zeolite Sn-Beta-H was developed, which involved alkali-induced degradation of all-silica Beta (Si-Beta) and self-assembly of the resultant Si-Beta fragments with SnCl2·2H2O in the hydrothermal condition templated with tetraethylammonium hydroxide (TEAOH) and polydiallydimethylammonium chloride (PDADMAC). The synthesized Sn-Beta-H zeolite was comprehensively characterized by means of XRD, N2 physisorption, TEM, UV–vis, XPS, TG, DRIFT, and FTIR spectroscopy with pyridine and deuterated acetonitrile adsorption. The Lewis acidity related to isolated tetrahedrally coordinated Sn species in the hierarchical porous Beta framework was revealed, which existed in the form of partially hydrolyzed and framework-integrated species. The Sn-Beta-H zeolite worked efficiently in the catalytic transformation of a series of carbohydrates into methyl lactate, outperforming the microporous Sn-Beta and postsynthesized mesoporous meso-Sn-Beta counterparts. The influence parameters such as mesoporosity, hydrophilicity/hydrophobicity, and Lewis acidity on the glucose conversion were studied in detail.
研究领域:
催化化学
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材料科学
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产品关联
DOI
高影响因子
CATALYSIS COMMUNICATIONS
·
2023
·
IF 3.7
Haoxi Jiang,Xinyi Ni,Angjiong Jiang,Guochao Yang,Lingtao Wang
Zr-β zeolites were modified with second metals to catalyze the conversion of ethanol/acetaldehyde to 1,3-butadiene. The incorporation of Ta increases the Lewis acidity of Zr-β zeolite, resulting in higher catalytic activity than that of In, Y and Ce. Furthermore, the Zr-β zeolite that was first incorporated with Zr and then Ta with a Ta/Zr molar ratio of 1.5 exhibited greater catalytic activity of 57% conversion and 75% selectivity. Activity descriptors were proposed to calculate the reactivity of key reaction steps, which served as evidence that Ta incorporation enhances the aldol condensation and MPV reduction reaction activity, thus improving catalytic performance.
研究领域:
催化化学
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材料科学
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产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2025
·
IF 3.9
Yuhao Yang,Chunhua Wang,Jiani Cai,Ying-Ya Liu,Zhiquan Yu,Zhichao Sun,Yao Wang,Anjie Wang,Chong Peng
Selective hydrogenation of phenol to cyclohexanone is of great significance for the production of value-added chemical intermediates and products. Pd/MIL-100(Cr), featuring highly dispersed Pd nanoparticles (∼2.5 nm), were synthesized using a double-solvent impregnation method followed by NaBH4 reduction. During aqueous-phase phenol hydrogenation, the catalyst achieved full conversion with 98.3% selectivity toward cyclohexanone within 1 h at 0.1 MPa and 100 °C. The catalyst exhibited high stability, maintaining performance up to 5 cycles without deactivation. The Lewis acidity of MIL-100(Cr) significantly influenced the phenol hydrogenation selectivity. By incorporation of Al, V, and Ce species into the MIL-100(Cr) framework, cyclohexanone selectivity in phenol hydrogenation was found to increase with the amount of Lewis acid sites (LAS). The acid properties of the Pd/MIL-100 catalysts were investigated using NH3-TPD, pyridine-adsorbed FT-IR, and EPR probe molecules. The interaction between Pd nanoparticles and the coordinatively unsaturated sites from the trimeric clusters of MIL-100 was found to be crucial in determining the Lewis acidity of the Pd/MIL-100 catalysts. Demonstrating a synergistic effect between the Pd and LAS, Pd/MIL-100(Cr) emerges as a promising candidate for the selective hydrogenation of phenol to cyclohexanone.
研究领域:
催化化学
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材料科学
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绿色化学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）