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Floret-like Fe–N nanoparticle-embedded porous carbon superstructures from a Fe-covalent triazine polymer

《化学科学与工程前沿(英文)》 2023年 第17卷 第5期   页码 525-535 doi: 10.1007/s11705-022-2232-5

摘要: Fe–Nx nanoparticles-embedded porous carbons with a desirable superstructure have attracted immense attention as promising catalysts for electrochemical oxygen reduction reaction. Herein, we employed Fe-coordinated covalent triazine polymer for the fabrication of Fe–Nx nanoparticle-embedded porous carbon nanoflorets (Fe/N@CNFs) employing a hypersaline-confinement-conversion strategy. Presence of tailored N types within the covalent triazine polymer interwork in high proportions contributes to the generation of Fe/N coordination and subsequent Fe–Nx nanoparticles. Owing to the utilization of NaCl crystals, the resultant Fe/N@CNF-800 which was generated by pyrolysis at 800 °C showed nanoflower structure and large specific surface area, which remarkably suppressed the agglomeration of high catalytic active sites. As expect, the Fe/N@CNF-800 exhibited unexpected oxygen reduction reaction catalytic performance with an ultrahigh half-wave potential (0.89 V vs. reversible hydrogen electrode), a dominant 4e transfer approach and great cycle stability (> 92% after 100000 s). As a demonstration, the Fe/N-PCNF-800-assembled zinc–air battery delivered a high open circuit voltage of 1.51 V, a maximum peak power density of 164 mW·cm–2, as well as eminent rate performance, surpassing those of commercial Pt/C. This contribution offers a valuable avenue to exploit efficient metal nanoparticles-based carbon catalysts towards energy-related electrocatalytic reactions and beyond.

关键词: Fe–Nx nanoparticles     hypersaline-confinement conversion     floret-like carbon     covalent triazine polymers     oxygen reduction reaction    

Covalent triazine framework with efficient photocatalytic activity in aqueous and solid media

Cyrine Ayed, Wei Huang, Kai A. I. Zhang

《化学科学与工程前沿(英文)》 2020年 第14卷 第3期   页码 397-404 doi: 10.1007/s11705-019-1884-2

摘要: Covalent triazine frameworks (CTFs) have been recently employed for visible light-driven photocatalysis due to their unique optical and electronic properties. However, the usually highly hydrophobic nature of CTFs, which originates from their overall aromatic backbone, leads to limitations of CTFs for applications in aqueous media. In this study, we aim to extend the range of the application media of CTFs and design hybrid material of a CTF and mesoporous silica (SBA-15) for efficient photocatalysis in aqueous medium. A thiophene-containing CTF was directly synthesized in mesopores of SBA-15. Due to the high surface area and the added hydrophilic properties by silica, the hybrid material demonstrated excellent adsorption of organic molecules in water. This leads not only to high photocatalytic performance of the hybrid material for the degradation of organic dyes in water, but also for efficient photocatalysis in solvent-free and solid state. Furthermore, the reusability, stability and easy recovery of the hybrid material offers promising metal-free heterogeneous photocatalyst for broader applications in different reaction media.

关键词: photocatalysis     covalent triazine framework     aqueous medium     SBA-15     solid state    

Cobalt nanoparticle decorated N-doped carbons derived from a cobalt covalent organic framework for oxygen

《化学科学与工程前沿(英文)》 2021年 第15卷 第6期   页码 1550-1560 doi: 10.1007/s11705-021-2104-4

摘要: The low cost and highly efficient construction of electrocatalysts has attracted significant attention owing to the use of clean and sustainable energy technologies. In this work, cobalt nanoparticle decorated N-doped carbons (Co@NC) are synthesized by the pyrolysis of a cobalt covalent organic framework under an inert atmosphere. The Co@NC demonstrates improved electrocatalytic capabilities compared to N-doped carbon without the addition of Co nanoparticles, indicating the important role of cobalt. The well-dispersed active sites (Co-Nx) and the synergistic effect between the carbon matrix and Co nanoparticles greatly enhance the electrocatalytic activity for the oxygen reduction reaction. In addition, the Co content has a significant effect on the catalytic activity. The resulting Co@NC-0.86 exhibits a superb electrocatalytic activity for the oxygen reduction reaction in an alkaline electrolyte in terms of the onset potential (0.90 V), half-wave potential (0.80 V) and the limiting current density (4.84 mA·cm–2), and a high selectivity, as well as a strong methanol tolerance and superior durability, these results are comparable to those of the Pt/C catalyst. Furthermore, the superior bifunctional activity of Co@NC-0.86 was also confirmed in a home-built Zn-air battery, signifying the possibility for application in electrode materials and in current energy conversion and storage devices.

关键词: cobalt embedment     N-doped carbons     covalent organic framework     oxygen reduction     Zn-air battery    

Co anchored on porphyrinic triazine-based frameworks with excellent biocompatibility for conversion of

《化学科学与工程前沿(英文)》 2022年 第16卷 第12期   页码 1761-1771 doi: 10.1007/s11705-022-2195-6

摘要: Microbial electrosynthesis is a promising alternative to directly convert CO2 into long-chain compounds by coupling inorganic electrocatalysis with biosynthetic systems. However, problems arose that the conventional electrocatalysts for hydrogen evolution may produce extensive by-products of reactive oxygen species and cause severe metal leaching, both of which induce strong toxicity toward microorganisms. Moreover, poor stability of electrocatalysts cannot be qualified for long-term operation. These problems may result in poor biocompatibility between electrocatalysts and microorganisms. To solve the bottleneck problem, Co anchored on porphyrinic triazine-based frameworks was synthesized as the electrocatalyst for hydrogen evolution and further coupled with Cupriavidus necator H16. It showed high selectivity for a four-electron pathway of oxygen reduction reaction and low production of reactive oxygen species, owing to the synergistic effect of Co–Nx modulating the charge distribution and adsorption energy of intermediates. Additionally, low metal leaching and excellent stability were observed, which may be attributed to low content of Co and the stabilizing effect of metalloporphyrins. Hence, the electrocatalyst exhibited excellent biocompatibility. Finally, the microbial electrosynthesis system equipped with the electrocatalyst successfully converted CO2 to poly-β-hydroxybutyrate. This work drew up a novel strategy for enhancing the biocompatibility of electrocatalysts in microbial electrosynthesis system.

关键词: microbial electrosynthesis     hydrogen evolution reaction     metalloporphyrins     biocompatibility     CO2 conversion    

Room temperature preparation of hydrazine-linked covalent organic frameworks coated capillaries for

《化学科学与工程前沿(英文)》 2023年 第17卷 第5期   页码 548-556 doi: 10.1007/s11705-022-2252-1

摘要: Covalent organic frameworks (COFs) have been increasingly used in capillary electrochromatography due to their excellent characteristics. In this work, hydrazine-linked TFPB-DHzDS (TFPB: 1,3,5-tris(4-formylphenyl)benzene; DHzDS: 2,5-bis(3-(ethylthio)propoxy)terephthalohydrazide) was first synthesized by a simpler and easier method at room temperature and introduced into capillary electrochromatography as coating material. The TFPB-DHzDS coated capillaries were prepared by an in-situ growth process at room temperature. After optimizing the coating concentration and experimental conditions of capillary electrochromatography, baseline separation of two groups of polycyclic aromatic hydrocarbons was achieved based on the TFPB-DHzDS coated capillary. And the established method was used successfully to determine PAHs in natural water and soil samples. The spiked recoveries of polycyclic aromatic hydrocarbons in these samples ranged from 90.01% to 111.0%, indicating that the method is reliable and could detect polycyclic aromatic hydrocarbons in natural samples. Finally, molecular simulation was applied to study and visualize the interaction between the analytes and coating COF materials to investigate the molecular level separation mechanism further.

关键词: hydrazine-linked TFPB-DHzDS     in-situ growth method     open-tubular capillary electrochromatography     molecular simulations    

Organic conjugated polymers and polymer dots as photocatalysts for hydrogen production

《能源前沿(英文)》 2021年 第15卷 第1期   页码 667-677 doi: 10.1007/s11708-021-0767-7

摘要: Owing to the outstanding characteristics of tailorable electronic and optical properties, semiconducting polymers have attracted considerable attention in recent years. Among them, organic polymer dots process large breadth of potential synthetic diversity are the representative of photocatalysts for hydrogen production, which presents both an opportunity and a challenge. In this mini-review, first, the organic polymer photocatalysts were introduced. Then, recent reports on polymer dots which showed a superior photocatalytic activity and a robust stability under visible-light irradiation, for hydrogen production were summarized. Finally, challenges and outlook on using organic polymer dots-based photocatalysts from hydrogen production were discussed.

关键词: polymer dots (Pdots)     photocatalysis     hydrogen production    

A mini review: Shape memory polymers for biomedical applications

Kaojin Wang, Satu Strandman, X. X. Zhu

《化学科学与工程前沿(英文)》 2017年 第11卷 第2期   页码 143-153 doi: 10.1007/s11705-017-1632-4

摘要: Shape memory polymers (SMPs) are smart materials that can change their shape in a pre-defined manner under a stimulus. The shape memory functionality has gained considerable interest for biomedical applications, which require materials that are biocompatible and sometimes biodegradable. There is a need for SMPs that are prepared from renewable sources to be used as substitutes for conventional SMPs. In this paper, advances in SMPs based on synthetic monomers and bio-compounds are discussed. Materials designed for biomedical applications are highlighted.

关键词: shape memory polymer     biodegradability     biocompatibility     biomedical application     bile acids    

Multifunctional antimicrobial chlorhexidine polymers by remote plasma assisted vacuum deposition

Ana Mora-Boza, Francisco J. Aparicio, María Alcaire, Carmen López-Santos, Juan P. Espinós, Daniel Torres-Lagares, Ana Borrás, Angel Barranco

《化学科学与工程前沿(英文)》 2019年 第13卷 第2期   页码 330-339 doi: 10.1007/s11705-019-1803-6

摘要: Novel antibacterial materials for implants and medical instruments are essential to develop practical strategies to stop the spread of healthcare associated infections. This study presents the synthesis of multifunctional antibacterial nanocoatings on polydimethylsiloxane (PDMS) by remote plasma assisted deposition of sublimated chlorhexidine powders at low pressure and room temperature. The obtained materials present effective antibacterial activity against K12, either by contact killing and antibacterial adhesion or by biocide agents release depending on the synthetic parameters. In addition, these multifunctional coatings allow the endure hydrophilization of the hydrophobic PDMS surface, thereby improving their biocompatibility. Importantly, cell-viability tests conducted on these materials also prove their non-cytotoxicity, opening a way for the integration of this type of functional plasma films in biomedical devices.

关键词: plasma polymers     conformal plasma deposition     chlorhexidine     bactericide     PDMS     biocompatibility    

Photoinduced dichroism and surface-relief-gratings of hyperbranched azo polymers synthesized by azo-coupling

CHE Pengchao, HE Yaning, WANG Xiaogong

《化学科学与工程前沿(英文)》 2007年 第1卷 第4期   页码 360-364 doi: 10.1007/s11705-007-0065-x

摘要: This article reports the synthesis and photoresponsive properties of a hyperbranched azo polymer containing electron donor-acceptor type azo chromophores both in backbone and peripheral positions. For the synthesis, a hyperbranched azo precursor polymer was synthesized by step-growth polymerization of an AB monomer, bis[2-(-ethylanilino)ethyl] 5-aminoisophthalate, through azo-coupling reaction. The hyperbranched precursor polymer was then reacted with the diazonium salt from 4-cyanoaniline to introduce donor-acceptor azo chromophores in the peripheral groups. The resulting azo polymers were characterized by the spectroscopic methods and thermal analysis. The photoinduced dichroism of the hyperbranched polymer was studied and its orientation order parameter was estimated to be 0.063. Thin films of the hyperbranched azo polymers were used to fabricate surface-relief-gratings (SRGs) by exposing them to an interference pattern of Ar laser beam at modest intensities (150 mW/cm). The azo chromophores introduced by post-azo-coupling reaction at the para-positions of the peripheral azobenzenes shows a significant effect on the SRG inscription rate. The hyperbranched azo polymers can potentially be used for applications such as reversible optical data storage, photoswitch, sensors, and other photo-driven devices.

关键词: inscription     4-cyanoaniline     orientation     peripheral     photoswitch    

Tetrazole tethered polymers for alkaline anion exchange membranes

Erigene Bakangura, Yubin He, Xiaolin Ge, Yuan Zhu, Liang Wu, Jin Ran, Congliang Cheng, Kamana Emmanuel, Zhengjin Yang, Tongwen Xu

《化学科学与工程前沿(英文)》 2018年 第12卷 第2期   页码 306-310 doi: 10.1007/s11705-017-1690-7

摘要: Poly(2,6-dimethyl-1,4-phenylene oxide) was tethered with a 1,5-disubstituted tetrazole through a quaternary ammonium linkage. The formation of a tetrazole-ion network in the resulting polymers was found to promote the hydroxide ion transport through the Grotthus-type mechanism.

关键词: anion exchange membrane     fuel cell     phase separation     tetrazole    

Synthesis and characterization of well-defined comb-like branched polymers

LI Aixiang, LU Zaijun, LÜ Zijian

《化学科学与工程前沿(英文)》 2008年 第2卷 第4期   页码 407-411 doi: 10.1007/s11705-008-0064-6

摘要: Well-defined comb-like branched polymers having one branch in each repeating unit have been successfully synthesized by the coupling reaction of living polystyrene (PS) and polyisoprene (PI) anions with 1, 1-diphenylethenyl (DPE) groups along PS backbone prepared via atom transfer radical polymerization (ATRP) of 4-vinylbenzyloxy benzophenone (Sc) followed by Wittig reaction. The resulting comb-like branched polymers were characterized by IR, H-NMR, gel permeation chromatography (GPC) and static light scattering (SLS) in detail. The effect of living chains and DPE group molar ratio on grafting efficiency was discussed. The results show the coupling reaction of living chains and DPE groups was highly effective, and the coupling efficiency can be controlled via the feed molar ratios of living chains and DPE groups. Moreover, the effect of molecular weights of backbone (PSe) and PSLi or PILi on grafting efficiency was also discussed. The results show that when excess living polymers were used, the almost quantitative grafting efficiency could be achieved.

关键词: grafting efficiency     polyisoprene     quantitative grafting     effective     molecular    

Thermal degradation characteristics and products obtained after pyrolysis of specific polymers found

Evangelia C. Vouvoudi, Aristea T. Rousi, Dimitris S. Achilias

《环境科学与工程前沿(英文)》 2017年 第11卷 第5期 doi: 10.1007/s11783-017-0996-5

摘要: Modern societies strongly support the recycling practices over simple waste accumulation due to environmental harm caused. In the framework of sustainable recycling of plastics from WEEE, pyrolysis is proposed here as a means of obtaining secondary value-added products. The aim of this study was to investigate the thermal degradation and the products obtained after pyrolysis of specific polymers found in the plastic part of WEEE, using thermogravimetric analysis and a pyrolizer equipped with a GC/MS. Polymers studied include ABS, HIPS, PC and a blend having a composition similar to that appearing in WEEE. It was found that, PC shows greater heat endurance compared to the other polymers, whereas ABS depolymerizes in three-steps. The existence of several polymers in the blend results in synergistic effects which decrease the onset and final temperature of degradation. Moreover, the fragmentation occurred in the pyrolyzer, at certain temperatures, resulted in a great variety of compounds, depending on the polymer type, such as monomers, aromatic products, phenolic compounds and hydrocarbons. The main conclusion from this investigation is that pyrolysis could be an effective method for the sustainable recycling of the plastic part of WEEE resulting in a mixture of chemicals with varying composition but being excellent to be used as fuel retrieved from secondary recycling sources.

关键词: Pyrolysis     WEEE recycling     ABS     HIPS     PC     Py-GC/MS     TGA    

Trihydrazinotriazine-grafting Fe

Jamal Rahimi, Seyedeh Shadi Mirmohammadi, Ali Maleki

《化学科学与工程前沿(英文)》 2021年 第15卷 第4期   页码 1008-1020 doi: 10.1007/s11705-020-1996-8

摘要: This study focuses on the synthesis and characterization of a novel magnetic nanocomposite 2,4,6-trihydrazino-1,3,5-triazine (THDT)-functionalized with silica-coated iron oxide magnetic nanoparticles (MNPs). This nanocomposite has porous morphology decorated with the spherical MNPs. Through co-precipitation of iron salts, MNPs were obtained. The prepared THDT was placed on the chlorine surface-modified MNPs. The present environment-friendly nanocatalyst intensely accelerated the synthesis of highly functionalized tetrahydrobenzo[ ]pyran derivatives as well as reduced the reaction times and increased yields of the products.

关键词: trihydrazino-triazine     porous     magnetic nanocatalyst     green chemistry     tetrahydrobenzo[b]pyrans    

Surface molecularly imprinted polymers for solid-phase extraction of (--)-epigallocatechin gallate from

Yunling Gao,Ying Hu,Kejian Yao

《化学科学与工程前沿(英文)》 2015年 第9卷 第4期   页码 467-478 doi: 10.1007/s11705-015-1526-2

摘要: Surface molecularly imprinted polymers (SMIPs) have been synthesized to selectively determine (−)-epigallocatechin gallate in aqueous media. SMIPs were prepared using a surface grafting copolymerization method on a functionalized silica gel modified with -cyclodextrin and vinyl groups. The morphology and composition of the SMIPs were investigated by scanning electron microscopy, Fourier transform-infrared spectroscopy and thermogravimetric analysis. In addition, the molecular binding capacity, recognition properties and selectivity of the SMIPs were evaluated. The imprinted polymers were found to have a highly specific recognition and binding capacity for (−)-epigallocatechin gallate in aqueous media which is the result of the hydrophobic properties of the -cyclodextrin and the hydrogen-bonding interactions of methacrylic acid. The SMIPs were successfully employed as solid-phase extraction adsorbents prior to the HPLC determination of (−)-epigallocatechin gallate in toothpaste. The HPLC analysis had a linear dynamic range of 0.5–50.0 µg?mL with a correlation coefficient of 0.9998 and the recoveries ranged from 89.4% to 97.0% with relative standard deviations less than 4.8%. The limit of detection and limit of quantification were 0.17 and 0.33 µg?mL , respectively. The method provides a promising approach for the preparation of selective materials for the purification and determination of complex samples.

关键词: β-cyclodextrin     (−)-epigallocatechin gallate     surface molecular imprinting     solid-phase extraction    

Microbial biodegradation of plastics: Challenges, opportunities, and a critical perspective

《环境科学与工程前沿(英文)》 2022年 第16卷 第12期 doi: 10.1007/s11783-022-1596-6

摘要:

● Health hazards of plastic waste on environment are discussed.

关键词: Plastic-waste     Polymers     Health-hazards     Biodegradation     Microorganisms     Enzymes    

标题 作者 时间 类型 操作

Floret-like Fe–N nanoparticle-embedded porous carbon superstructures from a Fe-covalent triazine polymer

期刊论文

Covalent triazine framework with efficient photocatalytic activity in aqueous and solid media

Cyrine Ayed, Wei Huang, Kai A. I. Zhang

期刊论文

Cobalt nanoparticle decorated N-doped carbons derived from a cobalt covalent organic framework for oxygen

期刊论文

Co anchored on porphyrinic triazine-based frameworks with excellent biocompatibility for conversion of

期刊论文

Room temperature preparation of hydrazine-linked covalent organic frameworks coated capillaries for

期刊论文

Organic conjugated polymers and polymer dots as photocatalysts for hydrogen production

期刊论文

A mini review: Shape memory polymers for biomedical applications

Kaojin Wang, Satu Strandman, X. X. Zhu

期刊论文

Multifunctional antimicrobial chlorhexidine polymers by remote plasma assisted vacuum deposition

Ana Mora-Boza, Francisco J. Aparicio, María Alcaire, Carmen López-Santos, Juan P. Espinós, Daniel Torres-Lagares, Ana Borrás, Angel Barranco

期刊论文

Photoinduced dichroism and surface-relief-gratings of hyperbranched azo polymers synthesized by azo-coupling

CHE Pengchao, HE Yaning, WANG Xiaogong

期刊论文

Tetrazole tethered polymers for alkaline anion exchange membranes

Erigene Bakangura, Yubin He, Xiaolin Ge, Yuan Zhu, Liang Wu, Jin Ran, Congliang Cheng, Kamana Emmanuel, Zhengjin Yang, Tongwen Xu

期刊论文

Synthesis and characterization of well-defined comb-like branched polymers

LI Aixiang, LU Zaijun, LÜ Zijian

期刊论文

Thermal degradation characteristics and products obtained after pyrolysis of specific polymers found

Evangelia C. Vouvoudi, Aristea T. Rousi, Dimitris S. Achilias

期刊论文

Trihydrazinotriazine-grafting Fe

Jamal Rahimi, Seyedeh Shadi Mirmohammadi, Ali Maleki

期刊论文

Surface molecularly imprinted polymers for solid-phase extraction of (--)-epigallocatechin gallate from

Yunling Gao,Ying Hu,Kejian Yao

期刊论文

Microbial biodegradation of plastics: Challenges, opportunities, and a critical perspective

期刊论文