Coatings
·
2021
·Vol. 11
·期 11
·1396
·
IF 2.881
Min Zhang,Dong Peng,Feifei Peng,Anwei Huang,Kaiqiang Song,Qingbing He,Changqing Yin,Jinsong Rao,Yuxin Zhang,Haitao Chen,Dalong Cong,Zhongsheng Li
The Al coatings were electrodeposited on the Cu substrate from AlCl3-EMIC ionic liquid (AlCl3:EMIC = 2:1 molar ratio) containing three cyanopyridine additives with different positions of the substituent group on the pyridine ring, which were 2-cyanopyridine, 3-cyanopyridine, and 4-cyanopyridine. The effects of cyanopyridine additives on the deposition potential, morphology, brightness, and corrosion properties of Al coatings were investigated. It was considered that the deposition potential of Al shifted to more negative overpotentials, the quality of Al coatings was promoted, and the corrosion property was improved by the cyanopyridine additives to a varying degree. Especially in the presence of 4-cyanopyridine, the flattest mirror bright Al coating was obtained, which had the smallest homogeneous nanocrystal grain size and strongest Al (200) crystallographic orientation. The average roughness Ra value was as low as 31 nm compared to that in the absence of cyanopyridine additives, which was 417 nm. Furthermore, the corrosion current density of the bright Al coating was three orders of magnitude lower than the rough Al coating, which resulted from the dense nanocrystal structure.Keywords:bright Al;electrodeposition;ionic liquids;cyanopyridine;additives
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ACS Applied Nano Materials
·
2022
·
IF 6.14
Guixiang Yang,Yuwei Wang,Ye Li,Chenglu Yan,Zhenxi Liu,Huiyong Wang,Huaqiao Peng,Juan Du,Baozhan Zheng,Yong Guo
Gold nanoclusters (AuNCs) have received extensive attention due to their outstanding biocompatibility and excellent optical and electrochemical properties. However, the disadvantages of lower quantum yield (QY, usually <10%) and time-consuming synthetic processes severely limit their wide applications. Herein, a rapid and convenient synthetic strategy for AuNCs with higher QY is developed. AuNCs with excellent photo-/thermal stability can be one-pot-synthesized in several minutes only using vitamin B1 (VB1) as both the stabilizer and reducing agent at room temperature, which can be used for the large-scale synthesis of AuNCs. More interesting is that the QY of AuNCs@VB1 can be easily modulated by pyridine (Py) and greatly enhanced to 66.27% (AuNCs@VB1/Py). To our knowledge, this is the first report on the synthesis of AuNCs with higher QY in several minutes using VB1 as a protective agent. The QY enhancement mechanism of AuNCs@VB1/Py is also investigated in detail, and it is proven that the electron injection from Py to AuNCs accelerates the irradiative transition and thus increases its fluorescent emission. Furthermore, fluorescence sensing for glutathione (GSH) and hypochlorite detection has been successfully constructed based on the suppressed fluorescence of AuNCs@VB1/Py by GSH and then restored by hypochlorite. In brief, this work offers a convenient strategy for rapid and large-scale synthesis of AuNCs with higher QY, which will have a wide range of applications in the fields of biolabeling, sensing, bioimaging, and so on.
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BIOORGANIC CHEMISTRY
·
2023
·
IF 5.1
Yangyang Sun,Zhuzhu Tang,Yanjun Li,Yongkang Song,Hualei Wang,Dongzhi Wei,Shengli Yang
Hydration, a secondary activity mediated by nitrilase, is a promising new pathway for amide production. However, low hydration activity of nitrilase or trade-off between hydration and catalytic activity hinders its application in the production of amides. Here, natural C-terminal-truncated wild-type nitrilase, mined from a public database, obtained a high-hydration activity nitrilase as a novel evolutionary starting point for further protein engineering. The nitrilase Nit-74 from Spirosoma linguale DSM 74 was successfully obtained and exhibited the highest hydration activity level, performing 50.7 % nicotinamide formation and 87.6 % conversion to 2 mM substrate 3-cyanopyridine. Steric hindrance of the catalytic activity center and the N -terminus of the catalytic cysteine residue helped us identify three key residues: I166, W168, and T191. Saturation mutations resulted in three single mutants that further improved the hydration activity of N -heterocyclic nitriles. Among them, the mutant T191S performed 72.7 % nicotinamide formation, which was much higher than the previously reported highest level of 18.7 %. Additionally, mutants I166N and W168Y exhibited a 97.5 % 2-picolinamide ratio and 97.7 % isonicotinamide ratio without any loss of catalytic activity, which did not indicate a trade-off effect. Our results expand the screening and evolution library of promiscuous nitrilases with high hydration activity for amide formation.
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PubMed
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NEW JOURNAL OF CHEMISTRY
·
2023
·Vol. 47
·期 28
·13279-13285
·
IF 3.3
Junling Guo,Zhongyi Cheng,Lukasz Peplowski,Zhemin Zhou
Isonicotinamide has important roles and application prospects in pharmaceutical, medical, and materials sciences. The biosynthesis of isonicotinamide has great advantages over chemical methods, but the biosynthesis of isonicotinamide has been reported for three decades and has not been industrialized yet. In this study, a thermophilic NHase from Carbonactinospora thermoautotrophicus was selected and then its activity was substantially improved by a “toolbox” screening strategy. The specific activity of the βL48D mutant towards 4-cyanopyridine was 307.02 ± 3.50 U mg−1, which was 13.9 times higher than that of the WT C.t NHase (22.01 ± 1.30 U mg−1). The structural analysis demonstrated that introduction of Asp into the βLeu48 site resulted in a larger catalytic cavity and better substrate orientations. Finally, a recombinant strain E. coli BL21 of the βL48D mutant was cultured at high cell density in a 5 L fermenter for high-level isonicotinamide production, developing a powerful process for isonicotinamide bio-production. The yield of isonicotinamide reached 2.89 M (352 g L−1), the substrate (4-cyanopyridine) was exhausted and the conversion was 100%. These results prove that C.t NHase is a promising competitor for future industrial production of biosynthetic isonicotinamide.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2018
·
IF 11.698
Zhishan Luo,Min Zhou,Xinchen Wang
In artificial photocatalysis, sluggish kinetics of hole transfer and the high recombination rate of charge have been the Achilles’ heel of photocatalytic conversion efficiency. The development of co-catalysts for promoting exciton splitting and charge separation has therefore gained continuous attention. Herein, “Co 4 O 4 ” cubane complex Co 4 O 4 (O 2 CMe) 4 (py) 4 ( 1a , py = pyridine derivatives), serves as a homogeneous molecular co-catalyst which is engineered into the framework of pristine polymeric carbon nitride (PCN) for water oxidation with light illumination. This modification strategy maximizes the contact areas between co-catalysts and reactants, reduces the over-potential of oxygen producing and accelerates the interface transfer rate of electron-hole pairs, thus leading to enhanced reaction kinetics for photocatalytic water oxidation. Compared with pristine PCN, the photocatalytic O 2 production rate up to 19-fold-enhanced in the presence of molecular co-catalyst. This work emphasizes the importance of developing effective, stable and earth-abundant molecular co-catalysts for the promotion of water-splitting photocatalysis.
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ACS Applied Materials & Interfaces
·
2015
·
IF 6.723
Guojian Chen,Xiaochen Wang,Jing Li,Wei Hou,Yu Zhou,Jun Wang
A family of nitrogen-enriched ultramicroporous carbon materials was prepared by direct carbonization of task-specifically designed molecular carbon precursors of cyanopyridinium-based crystalline dicationic salts (CISs). Varying the molecular structure of CISs, large surface area (918 m2 g–1), high N content (20.10 wt %), and narrow distributed ultramicropores (0.59 nm) can be simultaneously achieved on the sample PCN-14 derived from methyl-linked 4-cyanopyridinium D[4-CNPyMe]Tf2N. It therefore exhibited exceptional performance in greenhouse gas CO2 capture, i.e., simultaneously possessing (1) high CO2 adsorption uptakes: 5.33 mmol g–1 at 273 K, and 3.68 mmol g–1 at 298 K (both at 1.0 bar); (2) unprecedented selectivity of CO2 versus N2: 156; and (3) a high adsorption ratio of CO2 to N2: 148 (at 1.0 bar). This is the first time such a high selectivity and adsorption ratio over carbon materials has been achieved, which is among the highest values over solid adsorbents.
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JOURNAL OF MOLECULAR CATALYSIS B-ENZYMATIC
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2013
·
IF 2.823
Xiaolin Pei,Lirong Yang,Gang Xu,Qiuyan Wang,Jianping Wu
Microbial nitrile hydratases (NHases) are important industrial catalysts to produce valuable amides. However, only some NHase genes have been reported and studied at the molecular level. In this study, we developed a genome mining method to discover Fe-type NHases from GenBank. The putative NHase gene from Pseudomonas putida F1 was cloned and functionally expressed in Escherichia coli BL21 (DE3) by assisting of a putative activator gene adjacent to β-subunit region. Three recombinant plasmids containing NHase gene or the activator gene were designed and constructed. Maximal enzyme activity was obtained when the structural and activator genes were transcribed as one unit in plasmid pCDFDuet-1 at 18 °C. However, the expressed product did not show any NHase activity when the downstream activator gene was ignored, and the product completely existed in insoluble inclusion body. The activator gene might be involved in protein folding of the α- and β-subunits of NHase. In addition, the Fe-type NHase exhibited broad substrate specificity. The enzyme can efficiently hydrate aromatic nitriles, such as 3-cyanopyridine, 4-cyanopyridine, and benzonitrile, asides from aliphatic nitriles preferentially. Therefore, the recombinant NHase shows potential applications in some amides preparation.
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POLYHEDRON
·
2024
·
IF 2.4
Meng Zhao,Yun Yang,Xue-Song Gu,Lanlan Sun
The separation and purification of light hydrocarbons are performed by energy-intensive distillation processes. Microporous metal–organic framework based absorbents acting as alternative technology gains focus. Open metals sites (OMSs) enriched MOF-74 show great potential in light hydrocarbons but its separation selectivity is low and difficult to regenerate. To address this issue, we introduced N -donor ligands into open sites of Co-MOF-74 by post modification. Structure was determined by powder X-ray diffraction, element analysis, infrared spectroscopy and thermogravimetric analyses. As-synthesized modified Co-MOF-74 display potential in C 2 H 4 /C 2 H 6 , C 3 H 6 /C 3 H 8 , C 3 H 8 /CH 4 and C 2 H 6 /CH 4 separation for N -donor ligands placeholder.
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ACS Applied Nano Materials
·
2024
·
IF 5.3
Rui Xue,Rong Qiang,Yulong Shao,Xiao Yang,Qian Ma,Yi Chen,Fangjie Ren,Yuancheng Ding,Bowen Chen,Shijiang Feng
The construction of hierarchical structures has been demonstrated to be an effective method for achieving high-performance microwave absorption. In this study, a flower-like MoS2 nanosheet-coated tubular carbon composite with an average diameter of approximately 560 nm was synthesized via a straightforward ion-exchange and pyrolysis strategy. The growth of MoS2 nanosheets, the presence of heterojunction surfaces, and the construction of the hollow structure collectively enhance the dielectric loss of the material, thereby optimizing the microwave absorption properties of the material. The C@MoS2 nanocomposite demonstrates a minimum reflection loss of −66.8 dB and an effective absorption bandwidth of 4.8 GHz when the thickness is only 1.6 mm. This work presents a synergistic strategy for the design of layered hollow structures.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Yingxuan Wen,Fangfang Zhang,Jingru Dou,Shougui Wang,Fei Gao,Falong Shan,Jipeng Dong,Guanghui Chen
The abundant triazine rings with the good affinity for CO 2 molecules in covalent triazine frameworks (CTFs) can capture and activate CO 2 molecules, making CTFs a potential candidate for CO 2 cycloaddition reaction. However, due to the single active site, the realization of high catalytic performance commonly requires the assistance of cocatalysts or harsh reaction conditions. In this study, several novel ionic covalent triazine frameworks (MCTFs, BCTFs and YCTFs) multifunctional heterogeneous catalysts were synthesized for CO 2 cycloaddition reactions. The prepared CTFs catalysts have outstanding pore structure and uniformly distributed active sites (N Lewis basic sites in triazine ring and Cl – nucleophilic sites). The optimal catalyst MCTF-10 has good CO 2 enrichment capacity and high adsorption selectivity. In addition, the catalyst shows an outstanding catalytic performance for the coupling reaction of CO 2 and propylene oxide, with 96 % of yield and 99 % of selectivity for the product under metal-, solvent- and cocatalyst-free parameters (110 °C, initial CO 2 pressure 1 MPa, 4 h). Even under diluted CO 2 concentration (15 % CO 2 , 85 % N 2 ) and mild conditions (80 °C, 0.1 MPa, 24 h), the synthetized CTFs exhibits an outstanding catalytic activity. The excellent catalytic performance, along with the good cycling stability and broad applicability of epoxides, make it a competitive catalyst for catalyzing the CO 2 cycloaddition reaction.
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CHEMISTRY-A EUROPEAN JOURNAL
·
2025
·
IF 3.7
Jinghua Huang,Mingbao Huang,Jinan Li,Jie Zhang,Zhiyong Fu
Graphical A new thermoelectricity utilization system is established using tripyridinium–triazine compound for low-grade heat harvesting. The thermally induced potential shift arises from temperature-dependent interconversion between singlet and triplet states of the tripyridinium–triazine diradical. New energy technology is in urgent demand for waste heat harvesting and utilization for energy saving and renewable energy development. Herein, an aqueous organic redox flow battery (AORFB) with designed tripyridinium–triazine radicals ((TPyTz) ··4+ )/(TPyTz) ·5+ ) as the negative redox couple is constructed as a thermoelectricity utilization system. The electrochemical test indicates that the (TPyTz) ··4+ /(TPyTz) ·5+ couple shows an interesting potential change about 27 mV accompanied by system temperature varying from 298 K to 343 K. Nuclear magnetic resonance and electron paramagnetic resonance spectra approve that the population of high-energy (TPyTz) ··4+ triplet state increases with temperature rise. This shifts the potential of the (TPyTz) ··4+ /(TPyTz) ·5+ couple to a much more negative position. While the 2,2,6,6-tetramethylpiperidin-1-oxyl derivative (TPABPy)Cl 3 is used as the positive electrolyte with no temperature-dependent potential change, the AORFB established by these two couples displays a thermally induced potential change from 1.39 V to 1.42 V.
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