OPTICAL MATERIALS
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2020
·
IF 2.779
Xiaoshuo Zhang,Chunhua Li,Sheliang Zhao,Huiyun Pang,Yong Han,Xueli Luo,Wenzhi Tang,Zhonghong Li
Novel S-doped silicon quantum dots (S-SiQDs) were prepared by l -cysteine doped silicon quantum dots (SiQDs) for fluorescent detecting Fe 3+ in water. The as-prepared S-SiQDs sensor with an average diameter of 4.77 nm possessed richness of –NH 2 , endowing good water solubility and strong blue fluorescence. The quantum yield (QY) of ~66% was abtained when S-SiQDs exited at 345 nm. The synergistic effect of electron transfer that the electron of –NH 2 on S-SiQDs surface transfer to 3d unoccupied obrials of Fe 3+ , inner filter effectaccounted for fluorescence quenching. The probe possessed a relative wide liner range from 1 μmol/L to 20 μmol/L with the limit of detection (LOD) of 0.21 μmol/L to detecte Fe 3+ . The as-prepared S-SiQDs sensor could sensitively and selectively detect Fe 3+ in real water samples with satisfied recoveries of 90%–106%, which presented its potential applicability in the environmental fields.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2020
·
IF 4.939
Baofang Zhang,Renlian Chen,Zefan Yang,Yingxin Chen,Lihua Zhou,Yong Yuan
The heteroatom-doped porous carbon material as an alternative to commercial Pt/C catalysts in oxygen reduction reaction has attracted extensive attention. In this study, the rapeseed meal-based material (ARM-900) prepared by carbonization with high temperature and activation with ZnCl 2 had a porous structure and was doped with N and S heteroatoms. Compared to commercial Pt/C catalysts (onset potential of 0.95 V vs. RHE and limiting diffusion current of −5.7 mA cm −2 ), ARM-900 demonstrated excellent electrocatalytic performance with an onset potential of 0.98 V vs. RHE and limiting diffusion current of −8.1 mA cm −2 in O 2 saturated 0.1 M KOH solution. Meanwhile, ARM-900 had higher durability and more superior methanol tolerance than Pt/C catalyst. The excellent ORR performance of ARM-900 was derived from the formation of abundant pore structure and the doping of the autochthonous N and S heteroatoms. MFCs with ARM-900 as the cathode had the maximum power density of 808 mW/m 2 , which was obviously better than Pt/C (709 mW/m 2 ). This study provided an environment-friendly and effective strategy for the reuse of rapeseed meal and the preparation of N and S-doped non-metallic ORR catalysts.
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CHEMICAL ENGINEERING JOURNAL
·
2021
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IF 13.273
Yutong Luo,Jiaheng Qin,Guangxue Yang,Sha Luo,Ziming Zhao,Ming Chen,Jiantai Ma
The rational design and fabrication of distinctive coordination sites is an attractive and challenging approach to develop electrocatalysts with superior activity toward oxygen evolution reaction (OER). Constructing N-doped carbon shells coordinated with transitional metal composites can greatly enhance the OER activity of electrocatalysts. Herein, a facile electrochemical-pyrolysis strategy is applied to synthesize NiS/C 3 N 4 composite with N-Ni-S coordination sites by in-situ crystallization on copper foam (CF). A detailed characterization, especially synchrotron-based X-ray absorption fine structure (XAFS) clearly unravels the N-Ni-S coordination mode is successfully formed. As a result, NiS/C 3 N 4 presents excellent OER performance with a low overpotential of 334 mV at a current density of 10 mA cm −2 , a Tafel slope of 45 mV dec −1 , and robust electrochemical stability for 50 h in basic media, outperforming some recently reported conventional transitional metal electrocatalysts. The outstanding electrocatalytic performance of NiS/C 3 N 4 mainly originates from the N-Ni-S coordination sites, which can provide abundant catalytic active sites, facilitate charge transfer, and enhance electronic conductivity. Furthermore, by tuning the two important experimental parameters of electrodeposition potential and electropolymerization time, the relationship between morphology and electrocatalytic performance of catalysts is deeply explored. This work demonstrates the validity of improving electrocatalytic performance by elaborately tailoring the coordination sites, thereby opening up an applicable and inspiring avenue forward in the design of advanced electrocatalysts for water splitting.
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Polymers
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2020
·Vol. 12
·期 11
·2640
·
IF 3.426
Peng Dong,Jing Feng,Sujuan Li,Tingli Sun,Qingshan Shi,Xiaobao Xie
Starting from primary amine bearing cyclic carbonatetert-butyl-(2-oxo-1,3-dioxan-5-yl) carbamate (TBODC) and caprolactone (CL), amphiphilic poly(caprolactone-ran-amino trimethyl carbonate)s (P(CL-ran-ATC)s) random copolymers with controlled molecular weight and composition were synthesized via ring opening polymerization (ROP) and deprotection, using stannous octoate (Sn(Oct)2) as catalyst and benzyl alcohol (BnOH) as initiator. Therefore, hydrophilic/lipophilic ratio (HLR) of the P(CL-ran-ATC)s copolymers can be finely adjusted by the feed ratio of TBODC and CL. The antimicrobial activity againstStaphylococcus aureus(S. aureus) andEscherichia coli(E. coli) of P(CL-ran-ATC)s were proportional to HLR, and P(CL-ran-ATC)s presented more vigorous bactericidal activity towardsS. aureus. The minimum inhibitory concentration (MIC) values of P(CL-ran-ATC 50.9%) are 2000 μg mL−1and 3000 μg mL−1forS. aureusandE. coli. While P(CL-ran-ATC 50.9%) exhibited deficient hemolytic activity as 1.41%. In addition, the P(CL-ran-ATC)s showed extremely low cytotoxicity towards fibroblast L929 cells.Keywords:cyclic carbonate;primary amine;poly(ester-carbonate)s;antimicrobial activity;low hemolysis and cytotoxicity
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JOURNAL OF MEMBRANE SCIENCE
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2020
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IF 7.183
Diao Yuan,Yajun Qin,Songsong Li,Shenghua Du,Yaoyao Xu,Qiang Weng,Pei Chen,Xinbing Chen,Zhongwei An
A novel difluoro aromatic monomer DFTMTE is prepared, which contains five pendant ionizable methoxy and crosslinkable ethanedione groups. Block copolymers are developed via block copolycondensation of the monomers DFTMTE, 4,4′-difluorodiphenyl sulfone and 4,4′-diphenol. Sulfonated block ionomers are obtained via the following demethylation and nucleophilic substitution of the copolymers . The ionomer membranes with ion exchange capacity (IEC) of 1.80–2.16 mequiv. g −1 display high conductivity of 234–319 mS cm −1 at 80 °C and large maximum power density of 1730–2140 mW cm −2 , which is obviously larger than Nafion 212 (117 mS cm −1 and 1350 mW cm −2 ) in the same condition. Their enhanced performances are attributed to excellent microphase separations caused by block copolymer structures and multiple sulfonated side-chains integrating both rigid aromatic and flexible aliphatic units. Meanwhile, crosslinking further improves the balance among the properties of the membranes. For example, CB1SP having IEC of 1.80 mequiv. g −1 displays high comprehensive performance because of DFTMTE units and crosslinking structures, wherein low membrane swelling below 15% at 80 °C, large conductivity of 234 mS cm −1 , high maximum power density of 1730 mW cm −2 and good stability of the membrane electrolyte assembly indicate a high potential in the application of fuel cell.
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ACS Applied Materials & Interfaces
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2020
·
IF 8.758
Hairus Abdullah,Noto Susanto Gultom,Hardy Shuwanto,Worku Lakew Kebede,Dong-Hau Kuo
Zn(O,S) has been successfully doped with different amounts of Ho and characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), and transient photocurrent (TPC). The as-prepared Ho-doped Zn(O,S) catalysts with different Ho amounts are evaluated for hydrogen evolution reaction. The catalyst with the best performance in evolving hydrogen is further utilized to hydrogenate 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). It is found that doping with Ho obviously enhanced charge transfer and photoresponse properties of the catalyst. Therefore, the modified Zn(O,S) can optimally evolve hydrogen by 18 624 μmol/g, which is 20% higher than that of pristine Zn(O,S). Subsequently, the in situ generated hydrogen ions on catalyst surfaces also play an important role as a hydrogen source to hydrogenate 4-NP to 4-AP without any reducing agents such as NaBH4, which is commonly used as a hydrogen source. As Ho is doped in the lattices of Zn(O,S), it acts not only to separate photocarriers and to enhance the charge transfer but also to shorten the diffusion time of nitrophenolate ions to catalyst surfaces for further photocatalytic hydrogenation reaction (PHR) process. A plausible PHR mechanism has been provided to elucidate the great performance of Ho-modified Zn(O,S) for photocatalytic hydrogenation.
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Synthetic and Systems Biotechnology
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2020
·
IF 0
Ruida Wang,Fanjing Kong,Haizhen Wu,Bingbing Hou,Yajing Kang,Yuan Cao,Shiwei Duan,Jiang Ye,Huizhan Zhang
The lincosamide family antibiotic lincomycin is a widely used antibacterial pharmaceutical generated by Streptomyces lincolnensis , and the high-yield strain B48 produces 2.5 g/L lincomycin, approximately 30-fold as the wild-type strain NRRL 2936. Here, the genome of S. lincolnensis B48 was completely sequenced, revealing a ~10.0 Mb single chromosome with 71.03% G + C content. Based on the genomic information, lincomycin-related primary metabolism network was constructed and the secondary metabolic potential was analyzed. In order to dissect the overproduction mechanism, a comparative genomic analysis with NRRL 2936 was performed. Three large deletions (LDI-III), one large inverted duplication (LID), one long inversion and 80 small variations (including 50 single nucleotide variations, 13 insertions and 17 deletions) were found in B48 genome. Then several crucial mutants contributing to higher production phenotype were validated. Deleting of a MarR-type regulator-encoding gene slinc377 from LDI, and the whole 24.7 kb LDII in NRRL 2936 enhanced lincomycin titer by 244% and 284%, respectively. Besides, lincomycin production of NRRL 2936 was increased to 7.7-fold when a 71 kb supercluster BGC33 from LDIII was eliminated. As for the duplication region, overexpression of the cluster situated genes lmbB2 and lmbU , as well as two novel transcriptional regulator-encoding genes ( slinc191 and slinc348 ) elevated lincomycin titer by 77%, 75%, 114% and 702%, respectively. Furthermore, three negative correlation genes ( slinc6156 , slinc4481 and slinc6011 ) on lincomycin biosynthesis, participating in regulation were found out. And surprisingly, inactivation of RNase J-encoding gene slinc6156 and TPR (tetratricopeptide repeat) domain-containing protein-encoding gene slinc4481 achieved lincomycin titer equivalent to 83% and 68% of B48, respectively, to 22.4 and 18.4-fold compared to NRRL 2936. Therefore, the comparative genomics approach combined with confirmatory experiments identified that large fragment deletion, long sequence duplication, along with several mutations of genes, especially regulator genes, are crucial for lincomycin overproduction.
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2020
·
IF 3.807
Yingjie Chen,Zhihao Shi,Shanshan Li,Jianguang Feng,Beili Pang,Liyan Yu,Wenwu Zhang,Lifeng Dong
Heterogeneous nanoparticles with synergistic effects between different composites are potential catalysts with bifunctional catalytic activity for oxygen reduction (ORR) and oxygen evolution reaction (OER). Herein, heteroatoms such as N and S are doped into graphene substrates to improve catalytic activity and structural stability of Ag-MnFe 2 O 4 nanoparticles. Interestingly, these particles keep a primarily heterogeneous structure for their assembly on N, S-codoped graphene (NSG), while Ag domains shrink on S-doped graphene (SG) or N-doped graphene (NG). Subsequently, Ag-MnFe 2 O 4 /NSG shows the best bifunctional catalytic activity due to the improved stability of Ag-MnFe 2 O 4 NPs on NSG and enhanced bonding energy between supports and particles. The Koutecky-Levich plots confirm a major four-electron reaction pathway for the ORRs on Ag-MnFe 2 O 4 /NSG. Meanwhile, Ag-MnFe 2 O 4 /NSG exhibits higher stability and better methanol tolerance than commercial Pt/C. Therefore, Ag-MnFe 2 O 4 /NSG with bi-functional catalytic activity for ORR and OER is a promising non-Pt catalyst candidate.
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CARBOHYDRATE POLYMERS
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2020
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IF 7.182
Shixin Liu,Xiang Cai,Wei Xue,Dong Ma,Wu Zhang
We developed a co-delivery system of nitric oxide (NO) and antibiotic for the antibiotic-resistant bacterial infection therapy. The NO could disperse the bacterial biofilms and convert the bacteria into an antibiotic-susceptible planktonic form. Using the chitosan-graft-poly(amidoamine) dendrimer (CS-PAMAM) as the co-delivery system, methicillin (MET) and NO were conjugated successively to form CS-PAMAM-MET/NONOate. The positive CS-PAMAM could efficiently capture the negatively charged bacteria and PAMAM provide abundant reaction points for high payloads of NO and MET. The CS-PAMAM-MET/NONOate displayed effective and combined antibacterial activity to the E. coli and S. aureus . Particularly, for the MET-resistant S. aureus (MRSA), the CS-PAMAM-MET/NONOate displayed the synergistic antibacterial activity. In vivo wound healing assays also confirmed that CS-PAMAM-MET/NONOate could heal the infection formed by MRSA and then accelerate the wound healing effectively. Moreover, CS-PAMAM-MET/NONOate showed no toxicity towards 3T3 cells in vitro and rats in vivo , providing a readily but high-efficient strategy to drug-resistant bacterial infection therapy.
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JOURNAL OF PHYSICAL CHEMISTRY B
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2020
·
IF 2.857
Jia Zhao,Qi Lei,Fang He,Chen Zheng,Yang Liu,Xiaopeng Zhao,Jianbo Yin
The size influence of quaternary ammonium countercations in poly[4-styrenesulfonyl(trifluoromethylsulfonyl)imide][tetraalkylammonium] (P[STFSI][Nnnnn], n = 1, 2, and 3) poly(ionic liquid)s on dielectric polarization and the stimuli-responsive electrorheological effect is investigated by dielectric spectroscopy and rheology, and the microstructure-level understanding behind the influence is analyzed by Raman and X-ray scattering spectra. The size influence of quaternary ammonium cations is found to be nonmonotonic. The largest electrorheological effect accompanied by best polarization properties is demonstrated in P[STFSI][N2222]. Raman spectra and activation energy measurements demonstrate that the nonmonotonic influence originates from the fact that, compared to small N1111+ and large N3333+, intermediate N2222+ as countercations can contribute a higher mobile ion number and lower activation energy barrier of ion dissociation and motion. But the experimental values of activation energy are not consistent with theoretically calculated values by considering the ion pair electrostatic potential and elastic force contribution of the matrix. By X-ray scattering and diffraction characterizations, it is clarified that the nonmonotonic influence and the inconsistency of activation energy originate from the size influence of Nnnnn+ on the micromorphology of P[STFSI][Nnnnn]. Compared to the semicrystalline structure of P[STFSI][N1111] and the ionic aggregation structure of P[STFSI][N3333], the relatively uniform amorphous structure of P[STFSI][N2222] may be responsible for its lower activation energy barrier of ion motion. This study further provides insights into the design and preparation of future poly(ionic liquid)-based electrorheological materials by considering not only molecular structure but also micromorphology.
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BULLETIN OF MATERIALS SCIENCE
·
2020
·Vol. 43
·期 1
·1-6
·
IF 1.392
Li Lili,Yang Lin,Fu Bowen,Li Zhiqiang
Herein, we demonstrate a hot-injection method towards the fabrication of \(\hbox {Sb}_{2}\hbox {S}_{3}\) . The evolution from amorphous \(\hbox {Sb}_{2}\hbox {S}_{3}\) nanoparticles to a sheaf of \(\hbox {Sb}_{2}\hbox {S}_{3}\) nanorods cross-linked together occurring with the increase of reaction temperature and time is studied. The structural, compositional and morphological features of \(\hbox {Sb}_{2}\hbox {S}_{3}\) products indicate the formation of crystalline \(\hbox {Sb}_{2}\hbox {S}_{3}\) with orthorhombic phase and high purity. As the reaction proceeds, it can be observed that the individual nanorod grows along the elongated direction ( c -axis), and it is noteworthy that its round cross-section could develop into the rectangular cross-section subsequently. In this study we also propose a possible formation mechanism for the growth process of \(\hbox {Sb}_{2}\hbox {S}_{3}\) , and it reveals that the present hot-injection could provide an ideal growth environment for synthesizing the nanostructured materials by optimizing the experimental parameters.
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MACROMOLECULES
·
2020
·
IF 5.918
Jun Du,Die Huang,Hongkun Li,Anjun Qin,Ben Zhong Tang,Yongfang Li
Thiol–yne click polymerizations have become efficient synthetic tools for the construction of linear and hyperbranched polysulfides with advanced functionalities. However, the polymerization reaction of internal alkynes and thiols has been rarely utilized to prepare functional polymers. In this work, a catalyst-free click polymerization between activated internal alkyne and thiol was developed. The polymerizations of 4,4′-thiodibenzenethiol (1) with dibutynoates (2) and diphenylpropiolates (3) were performed in N,N-dimethylformamide (DMF) at 60 °C, producing poly(β-thioacrylate)s (PTAs) with high molecular weights (Mw up to 50300) and high stereoregularities (Z content up to 84%) in high yields (up to 91%). The click polymerization can be conducted smoothly in an open atmosphere without protection against moisture and oxygen. The resultant PTAs possess good solubility in common organic solvents and high optical transparency. Thanks to the high contents of sulfur atoms, ester groups, and aromatic rings in the polymers, their thin films show high refractive indices (n > 1.63) in the wavelength region of 400–1700 nm. Moreover, the PTAs containing tetraphenylethene moieties exhibit aggregation-induced emission characteristics.
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危险品化学品经营许可证（带存储）