Catalysts
·
2020
·Vol. 10
·期 3
·302
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IF 3.52
Meng Guo,Zhen Wei,Jianming Yang,Zunyuan Xie,Weiqiang Zhang
In the palladium-catalyzed C−C coupling reaction, electron-rich phosphine ligands and a catalytic amount of catalyst loading are required in most cases. Herein, a bench-stable, easily modified and less toxic alkynone was utilized in palladium-catalyzed Sonogashira coupling to replace conventional phosphine ligands. With 1-(4-methoxyphenyl)-3-phenyl-2-yn-1-one (L2) as the ligand, catalyst loading was reduced to 5-10 ppm. In this newly developed catalytic system, a variety of (hetero)arene iodines and alkynes could be tolerated, resulting in good yields of the corresponding cross-coupling products.Keywords:α;β-alkynone;Pd-catalyzed C−C coupling;π-acidicity
研究领域:
有机化学
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催化化学
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DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2023
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IF 8.2
Ying Kang,Xingmei Lu,Junli Xu,Qing Zhou,Guangjin Zhang,Jiayu Xin,Dongxia Yan,Ibrahim E.I. Tantawy E.I. Sayed
Transforming lignin into aromatic monomers is critically attractive to develop green and sustainable energy supplies. However, the usage of the additional catalysts like metal or base/acid is commonly limited by the caused repolymerized and environmental issues. The key step is to mediate electron transfer in lignin to trigger lignin C-C/C-O bonds cleavage without the catalysts mentioned above. Here, we report that the ionic liquids [BMim][ClO 4 ] was found to trigger lignin electron transfer to cleave the C-C/C-O bonds for aromatic monomers without any additional catalyst. The proton transfer from [BMim] + to [ClO 4 ] − could polarize the anion and decrease its structure stability, upon which the active hydroxyl radical generated and induced lignin C-C/C-O bonds fragmentation via free radical-mediated routes with the assistance of photothermal synergism. About 4.4 wt% yields of aromatic monomers, mainly composed of vanillin and acetosyringone , are afforded in [BMim][ClO 4 ] under UV-light irradiation in the air at 80 °C. This work opens the way to produce value-added aromatic monomers from lignin using an eco-friendly, energy-efficient, and simple route that may contribute to the sustainable utilization of renewable natural resources.
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高影响因子
Small
·
2023
·Vol. 19
·期 20
·2207821
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IF 13.3
Zelin Wang,Xidong Lin,Youchen Tang,Dongtian Miao,Junlong Huang,Yan Lu,Shaohong Liu,Ruowen Fu,Dingcai Wu
Carbon-based polymer brushes (CBPBs) are an important class of functional polymer materials, which synergistically combine the advantageous properties of both carbons and polymers. However, the conventional fabrication procedures of CBPBs involve tedious multistep modification, including preoxidation of carbon substrates, introduction of initiating groups, and subsequent graft polymerization. In this study, a simple yet versatile defect-engineering strategy is proposed for the efficient synthesis of high-grafting-density CBPBs with highly stable C C linkages via free radical polymerization. This strategy involves the introduction and removal of nitrogen heteroatoms in the carbon skeletons via a simple temperature-Fmed heat treatment, leading to the formation of numerous carbon defects (e.g., pentagons, heptagons, and octagons) with reactive C=C bonds in the carbon substrates. The as-proposed methodology enables the facile fabrication of CBPBs with various carbon substrates and polymers. More importantly, the highly grafted polymer chains in the resulting CBPBs are tethered with the carbon skeletons by robust C C bonds, which can endure strong acid and alkali environments. These interesting findings will shed new light on the well-orchestrated design of CBPBs and broaden their applications in various areas with fascinating performances.
研究领域:
材料科学
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聚合物化学
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表面化学
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DOI
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VACUUM
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2024
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IF 3.8
Xiu Wen,Zhixiu Yang,Lijing Gao,Ruiping Wei,Xiaomei Pan,Jin Zhang,Guomin Xiao
Electrocatalytic reduction of CO 2 affords a potential way to mitigate the greenhouse effect and fuel crisis. In this work, we compared highly-dispersed CuO nanocomposites and Cu–Cu 2 O nanocomposites which all derived from Cu x Al-LDH for CO 2 electrochemical reduction . The Cu–Cu 2 O based nanocomposites obtained through the restoration strategies still retain its layered structure, simultaneously increasing dual Cu–Cu 2 O active sites, which exhibit excellent performance in selective reduction of CO 2 to C 2 H 4 . The Cu 5 Al-ER obtained through in-situ electrochemical reduction is modified by bulk phase, which can regulate active species, increase surface active sites, enhance C–C coupling. Meanwhile, the electrochemical strategy offers numerous benefits, including gentle conditions, adjustable monitoring, exceptional efficiency and adaptability. We have confirmed that cost-effective Cu–Cu 2 O based nanocomposite derived from Cu 5 Al-LDH can effectively promote C–C coupling during electrochemical CO 2 conversion and improve FE C2H4 . The FE C2H4 of Cu 5 Al-ER reaches 36% at −1.2 V vs. RHE. And the current density reaches −172 mA·cm −2 at −1.6 V vs. RHE. The results showed that compared to Cu 5 Al-LDO, the FE C2H4 of Cu 5 Al-ER increased by 2.6 times. In addition, Cu 5 Al-ER exhibits excellent stability during the 12 hours CO 2 catalytic reduction process.
研究领域:
化学
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环境科学
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能源科学
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DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2020
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IF 16.683
Lixia Li,Juanhua Kong,Huimin Zhang,Sijie Liu,Qiang Zeng,Yaqin Zhang,Hao Ma,Hongyan He,Jinxing Long,Xuehui Li
The catalytic depolymerization process for lignin to produce value added chemicals is often challenged by the limited mass transfer over heterogeneous catalysts, the complex aromatic biopolymer structures, and the high recalcitrance of C C bonds. Herein, a series of hierarchical MFI nanosheets (MFI-ns) supported metal oxide catalysts have been designed and used for the selectively oxidative cleavage of organosolv lignin. As expected, 81.6 % conversion of lignin can be achieved over 15Ce-5Cu/MFI-ns with 294.0 mg g −1 yield of volatile products, including 180.9 mg g −1 of diethyl maleate. Quantum chemistry calculation coupled with static adsorption measurements shows that the superior catalytic activities of these catalysts are ascribed to the favorable mass transport of lignin to the active sites by the unique layer structure, and the hierarchical pore sizes distribution, as well as the electronic effect between Cu and Ce components. In addition, the catalytic mechanism for the cleavage of C C bonds in β -O-4 model probes has been studied via the controlled oxidative degree of model compounds and the isotope-labeling experiments. Therefore, this work provides a new insight into the efficient utilization of lignin via the rational design of catalysts.
研究领域:
化学工程
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材料科学
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催化反应
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DOI
高影响因子
Nature Communications
·
2022
·Vol. 13
·期 1
·1-8
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IF 17.694
Zhou Xian,Gao Xiaofeng,Liu Mingjie,Gao Zirui,Qin Xuetao,Xu Wenhao,Ye Shitong,Zhou Wenhua,Fan Haoan,Li Jing,Fan Shurui,Yang Lei,Fu Jie,Xiao Dequan,Lin Lili,Ma Ding,Yao Siyu
The coupling of acetonitrile into succinonitrile, an important terminal dinitrile for value-added nylon production, via a dehydrogenative route is highly attractive, as it combines the valuable chemical synthesis with the production of green hydrogen energy. Here, we demonstrate that it is possible to achieve a highly selective light driven dehydrogenative coupling of acetonitrile molecules to synthesize succinonitrile using anatase TiO 2 based photocatalysts in aqueous medium under mild conditions. Under optimized conditions, the formation rate of succinonitrile reaches 6.55 mmol/(g cat *h), with over 97.5% selectivity to target product. Mechanism studies reveal that water acts as cocatalyst in the reaction. The excited hole of anatase semiconductor oxidizes water forming hydroxyl radical, which subsequently assists the cleavage of sp 3 C-H bond of acetonitrile to generate ·CH 2 CN radical for further C-C coupling. The synergy between TiO 2 and Pt cocatalyst is important to enhance the succinonitrile selectivity and prevent undesirable over-oxidation and hydrolysis. This work offers an alternative route to prepare succinonitrile based on renewable energy under mild conditions and avoid the use of toxic reagents and stoichiometric oxidative radical initiators.
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PubMed
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2022
·
IF 24.319
Yuqing Ren,Yao Chen,Qingfei Zhao,Zhenmin Xu,Meijun Wu,Zhenfeng Bian
As a typical C-C coupling catalyst, the exposed crystalline facets of palladium nanoparticles (Pd NPs) greatly affect the selectivity and activity of the reaction. Here, we utilize a pioneering photocatalytic dissolution technique to controllably expose specific crystalline facets on Pd NPs. This top-down etching scheme selectively passivates the edges of single-crystal Pd nanocubes and exposes the {111} facets, which results in an 84% increase in photocatalytic Suzuki coupling reaction yields. Moreover, this approach is also applicable to improve the activity of commercial Pd/C, and Pd/Al 2 O 3 catalysts. This technique is expected to open a new path in the field of nanoparticle crystallographic conversion.
研究领域:
材料科学
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化学工程
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催化科学
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DOI
高影响因子
JOURNAL OF CATALYSIS
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2017
·
IF 6.844
Huifang Liu,Min Wang,Hongji Li,Nengchao Luo,Shutao Xu,Feng Wang
Catalytic oxidation of C C bond is a key technology to transform petroleum-based as well as sustainable biomass feedstock into more valuable oxygenates. We herein describe a convenient and useful oxidation strategy of converting ketones into carboxylic acids using homogeneous copper catalyst without additives and with O 2 as the terminal oxidant. A wide range of aryl and aliphatic ketones as well as β–O–4 lignin models were selectively oxidized to acids via C C bond cleavage. Mechanism studies by EPR and in situ NMR elucidate the principles of Cu/O 2 reactivity that involves C H bond and O 2 activation via a peroxide species. This provides an important foundation for expanding the scope of useful aerobic oxidation reactions using copper catalysts.
研究领域:
有机化学
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催化化学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2025
·
IF 4.8
Jianhao Li,Zhicheng Hu,Shuhuan Han,Dapeng Cao,Xiaofei Zeng,Jianfeng Chen
Electrocatalytic CO 2 reduction reaction (CO 2 RR) to multi-carbon product, especially for ethylene (C 2 H 4 ), provides a favorable pathway for carbon neutrality and renewable energy storage. However, the second-order C-C coupling reactions in CO 2 RR need always the high activation/driven energy in dynamics originating from the trace C 1 intermediate product. Herein, we synthesized the Ag-decorated Cu 2 O porous hollow core-shell catalyst named Ag@Cu 2 O where Ag nanoparticles uniformly distributed on inner the surface of the hollow Cu 2 O (H-Cu 2 O) via the sacrificial template method. Benefiting from the synergistic hollow structure and electron transfer from Cu and Ag to O, Ag@Cu 2 O catalyst delivers the excellent C 2 H 4 Faradaic Efficiency (FE) of 55 % ± 2 % at −1.0 V (vs. RHE), which is superior to the most reported catalysts. More importantly, in situ infrared spectroscopy and density functional theory (DFT) calculations reveal the introduction of Ag can decrease the activation energy required for *CO and C-C coupling.
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2024
·
IF 10.8
Handan Zhang,Liping Li,Xinhui Liu,Linshuai Duan,Xin Zhang,Lu Dong,Xiqin Liu,Pengcheng Li,Bohan Li,Mengzhu Xue,Guohui Xia
Humin, endowed with abundant redox functional groups, can be reduced anaerobically under dark. When reduced humin encounters O2, the possibility of ·OH formation arises. However, the exploration of ·OH generation mediated by humin has not been comprehensively conducted. The study found that O2 oxidized the reduced humin, generating 8.61 μmol/g of ·OH. After isolating humin using the methyl isobutyl ketone (MIBK) method, the lipid component was identified as the primary contributor to ·OH generation. Subsequent polar separation revealed that the lipid fraction extracted from the ethanol–water mixture with a volume ratio of 7:3 (LFEW7:3) played the most significant role in ·OH production. Further characterization confirmed that the simultaneous presence of aromatic C═C and C═O were the predominant features contributing to the ·OH generation. The ·OH generation experiments with humin-pyridine analogue compound demonstrated that polycyclic pyridine N (≥3 rings) played a significant role in promoting the ·OH generation. Most importantly, the study compared the ·OH production by humin and homologous humic acid, indicating that ·OH generated by humin was higher than that of humic acid. Overall, these affirmative findings manifested the overlooked role of humin in ·OH production and offered valuable insights into the mechanism of ·OH generation by humin in the dark.
研究领域:
环境科学
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生物化学
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PubMed
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CHEMICAL ENGINEERING JOURNAL
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2024
·
IF 13.3
Handan Zhang,Liping Li,Xinhui Liu,Xin Zhang,Xiqin Liu,Lu Dong,Pengcheng Li,Mengzhu Xue,Bohan Li,Guohui Xia
The production of hydroxyl radicals (·OH) via reduced humin oxygenation is well established. As biochar is widely used in environmental restoration, its coexistence with humin in restored soils may affect ·OH generation due to its electron transfer ability. However, the role of biochar in ·OH generation by humin remains largely unexplored. Herein, we investigated the ·OH generation by humin-biochar at different mass ratios. Our results indicated that biochar could significantly enhance the ·OH production by humin when the mass of humin exceeded that of biochar. Notably, when the mass ratio of humin to biochar was 50, the ·OH produced reached 75.1 μM, which is nearly 1.7 times the amount generated by humin alone (43.1 μM). Both single-electron and two-electron transfer pathways coexisted in ·OH generation by humin-biochar. C = O in humin were necessary conditions for the production of ·OH, while the presence of C = C in biochar promoted the generation of ·OH. Using graphene and carbon nanotubes both rich in C = C groups as the model compounds, humin-graphene and humin-carbon nanotubes produced ·OH at 122 μM and 98.8 μM, respectively, significantly higher than those generated by humin alone (43.1 μM). This result confirmed the promoting effect of aromatic C = C on ·OH generation. By contrast, when the biochar mass was greater than or equal to that of humin, ·OH generation was inhibited due to the significant reduction of C = O. In this case, environmentally persistent free radicals (EPFRs) in biochar were the primary structures responsible for ·OH production. This study provides comprehensive insights for the first time into the influence of biochar on ·OH generation by humin and offers a new potential method for the green and efficient removal of pollutants.
研究领域:
环境科学
·
土壤学
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高影响因子
INORGANIC CHEMISTRY
·
2021
·
IF 5.165
Heng-Zhi Liu,Bo Li,Haiqiang Luo,Xiaohang Qiu,Jian-Gong Ma,Peng Cheng
Metal–organic frameworks (MOFs) represent an ideal platform for the construction of highly active composite catalysts. However, loading metastable and/or multicomponent metal compounds into MOFs remains a synthetic bottleneck due to the great challenge of keeping the guest and matrix intact during the preparation of a composite. In this work, we develop a new impregnation reduction surface modification (IRSM) strategy to give a new composite catalyst CuCl@MIL-101(Cr), which is successfully postmodified by in situ construction of CuII defects on the surface of loaded CuCl inside MOF pores, leading to the new composite material CuII/CuI@MIL-101(Cr). The new dual-component composite catalyst exhibits a hierarchical structure and superior catalytic activity in C–C homocoupling of arylboronic acids under green conditions. This study presents a facile strategy for improving the catalytic activity by constructing defects on the surface of MOF-based catalysts as well as for forming multiple-component composite materials.
研究领域:
材料科学
·
催化化学
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DOI
PubMed
高影响因子
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