1. |
- Aristote, Nkongolo Tshamala, et al.
(författare)
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Methods of improving the initial Coulombic efficiency and rate performance of both anode and cathode materials for sodium-ion batteries
- 2022
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Ingår i: Chinese Chemical Letters. - : Elsevier BV. - 1001-8417 .- 1878-5964. ; 33:2, s. 730-742
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Tidskriftsartikel (refereegranskat)abstract
- Sodium-ion batteries (SIBs) have gained more scientists’ interest, owing to some facts such as the natural abundance of Na, the similarities of physicochemical characteristics between Li and Na. The irreversible Na+ ions consumption during the first cycle of charge/discharge process (due to the formation of the solid electrolyte interface (SEI) on the electrode surface and other irreversible reactions) is the factor that determines high performance SIBs and largely reduces the capacity of the full cell SIBs. Thus, the initial coulombic efficiency (ICE) of SIBs for both anode and cathode materials, is a key parameter for high performance SIBs, and the point is to increase the transport rate of the Na+ ions. Therefore, developing SIBs with high ICE and rate performance becomes vital to boost the commercialization of SIBs. Here we provide a review on the methods to improve the ICE and the rate performance, by summarizing some methods of improving the ICE and rate performance of the anode and cathode materials for SIBs, and end by a conclusion with some perspectives and recommendations.
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2. |
- Chen, Bin, et al.
(författare)
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Modulation of photovoltaic behavior of dye-sensitized solar cells by electron donors of porphyrin dyes and cosensitization
- 2015
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Ingår i: Chinese Chemical Letters. - : Elsevier BV. - 1001-8417 .- 1878-5964. ; 26:7, s. 899-904
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Tidskriftsartikel (refereegranskat)abstract
- Porphyrin dyes have received great attention due to their excellent photovoltaic performance in dye-sensitized solar cells (DSSCs). In this work, dyes XC1-XC3 were synthesized by introducing various numbers of bis(4-methoxyphenyl)amino and p-hexyloxyphenyl groups to porphyrin mesa-positions. The XC1 molecule contains two p-hexyloxyphenyl groups, and its DSSCs showed the power conversion efficiency of 4.81%. For XC2 and XC3, the replacement of p-hexyloxyphenyl with diphenylamino groups can effectively enhance the light harvesting around 500 nm. However, the highest occupied molecular orbitals (HOMOs) were elevated too much, which suppressed the dye regeneration processes, leading to low cell efficiencies of 2.51% and 1.27% for XC2, and XC3, respectively. To further improve the cell performance, an anthracene derivative C1 was used as the cosensitizer for XC1, which increased both the J(sc) and V-oc values, with an improved efficiency of 5.75%.
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3. |
- Ding, Pengjia, et al.
(författare)
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NiCo2O4 hollow microsphere–mediated ultrafast peroxymonosulfate activation for dye degradation
- 2021
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Ingår i: Chinese Chemical Letters. - : Elsevier. - 1001-8417 .- 1878-5964. ; 32:8, s. 2495-2498
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Tidskriftsartikel (refereegranskat)abstract
- Morphology and dispersity are key factors for activating peroxymonosulfate (PMS). In this study, we designed a recyclable open-type NiCo2O4 hollow microsphere via a simple hydrothermal method with the assistance of an NH3 vesicle. The physical structure and chemical properties were characterized using techniques such as scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), N2 adsorption and X-ray photoelectron spectroscopy (XPS). The test results confirm that the inner and outer surfaces of open-type NiCo2O4 hollow-sphere can be efficiently utilized because of the hole on the surface of the catalyst, which can minimize the diffusion resistance of the reactants and products. Under optimized conditions, the total organic carbon (TOC) removal efficiency of rhodamine B (RhB) can reach up to 80% in 40 min, which is almost 50% shorter than the reported values. The reactive radicals were identified and the proposed reaction mechanism was well described. Moreover, the disturbances of HCO3−, NO3−, Cl− and H2PO4− were further investigated. As a result, HCO3− and NO3− suppressed the reaction while Cl− and H2PO4− had a double effect on reaction.
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4. |
- Guo, Xugeng, et al.
(författare)
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Recent research progress for upconversion assisted dye-sensitized solar cells
- 2021
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Ingår i: Chinese Chemical Letters. - : Elsevier. - 1001-8417 .- 1878-5964. ; 32:6, s. 1834-1846
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Forskningsöversikt (refereegranskat)abstract
- Upconversion (UC) technology makes it possible to harvest infrared (IR) light from the sun and has increasingly been employed in recent years to improve the efficiency of solar cells. The progress in the area concerns both research on fundamental principles and processes of UC and technologies of device fabrication. Significant increase of important solar cell parameters, like short-circuit photocurrent density and open-circuit photovoltage as well as the total photon-to-current efficiency, has been accomplished. We here review the research published during the last few years in the area, in particular we consider the two most cherished techniques, namely the incorporation of upconverting nanophosphors directly into the photoanodes of the solar cells and the introduction of plasmonic metal nanoparticles co-existing with the UC particles. Other ways to achieve strong field enhancement, and the use of the non-linear nature of UC, is to apply microlenses, with or without assisting plasmonic excitation. Further enhanced UC action has been demonstrated by broad band and effective harvesting by organic IR antennas, with subsequent mediation by an intermediate nanoshell of the energy into the upconverting core. Codoping, nanohybrid and layer-by-layer technologies involving upconverting particles as well as the use of upconverting nanoparticles in hole-transport and electrolyte layers, tested in recent works, are also reviewed. While most of these technologies employ upconverting rare earth metals for sequential photon absorption, the main alternative technique, namely triplet-triplet annihilation UC using organic materials, is also reviewed. It is our belief that all these approaches will be further much researched in the near future, with potentially great impact on solar cell technology.
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5. |
- Li, D. Z., et al.
(författare)
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Study of interaction between red-tide toxin, domoic acid and double-stranded DNA by capillary zone electrophoresis
- 2004
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Ingår i: Chinese Chemical Letters. - 1001-8417 .- 1878-5964. ; 15:9, s. 1079-1082
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Tidskriftsartikel (refereegranskat)abstract
- The interactions between amnesic red-tide toxin, domoic acid (DA) and 14mer double-stranded DNA (dsDNA with three kinds of sequences) were studied by capillary zone electrophoresis (CZE). For the dsDNA with a sequence of 5'-CCCCCTATACCCGC-3', the amount of free dsDNA decreases with the increase of added DA; and the signal of DA-dsDNA complex was observed. Meanwhile, the other two dsDNAs, 5'-(C)12GC-3' and 5'-(AT)7-3', the existence of DA could not lead to the change of dsDNA signal and indicated that there is no interaction between DA and these two dsDNAs.
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6. |
- Ma, G. B., et al.
(författare)
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Novel monomeric phenanthroline-thallium(III) complexes multinuclear NMR characterization in organic solvents
- 2002
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Ingår i: Chinese Chemical Letters. - 1001-8417 .- 1878-5964. ; 13:7, s. 695-698
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Tidskriftsartikel (refereegranskat)abstract
- A novel complex of monomeric thallium(III) with the nitrogen donor ligand phenanthroline (phen) has been prepared and characterized by multinuclear NMR (H-1, C-13, Tl-205). The three complexes exist in equilibria in DMSO and acetonitrile solution which was proved by the Tl-205 NMR spectra. The H-1 and C-13 NMR spectra of tris-phen Tl(III) complex have been measured, where the spin-spin coupling between Tl (I = 1/2) and C-13 or H-1 signals were observed with the H-1 and C-13 NMR spectroscopy in acetonitrile. The coupling constants are presented and the chemical shifts of complexes are discussed in detail.
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7. |
- Shi, F., et al.
(författare)
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Synthesis and characterization of two novel high valent dinuclear complexes with a triphenolate ligand bearing functional groups
- 2005
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Ingår i: Chinese Chemical Letters. - 1001-8417 .- 1878-5964. ; 16:1, s. 89-92
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Tidskriftsartikel (refereegranskat)abstract
- Two novel high valent complexes [M-2(III, III)L(mu-OAc)(2)](PF6)-P-. (M=Mn, Fe; 9) were prepared, where L was the tri-anion of 2,6-bis{[(2-hydroxy-3-(morpholin-4-yl methyl)-5-tertbutyl benzyl)(pyridyl-2-methyl)amino]methyl}-4-methyl phenol which contained additional phenolic, tert-butyl and morpholin-4-yl methyl groups compared to its parent [Mn-2(II, II)(bpmp) (mu-OAc)(2)](CIO4)-C-. (10). These improvements decreased the difference between the new model and (Mn)(4) cluster (OEC in nature).
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8. |
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9. |
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10. |
- Sun, S. G., et al.
(författare)
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Studies of a series of novel rhenium(I) bipyridyl dyes for solar cells
- 2005
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Ingår i: Chinese Chemical Letters. - 1001-8417 .- 1878-5964. ; 16:5, s. 677-680
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Tidskriftsartikel (refereegranskat)abstract
- A series of novel rhenium(I) 2,2'-bipyridyl complexes [fac-Re(4,4'-di-COOEt-bpy)-(CO)(3)(Xpy)PF6], where bpy is 2,2'-bipyridine, py is pyridine and X is 3-methyl, 3-hydroxy, or 3-amino, were synthesized, their photophysical and electrochemical properties were studied. The Re(II/I) oxidation potentials decreased as the X group becomes more electron donating from H to 3-methyl, 3-hydroxy, or 3-amino, which might be a very convenient ways for adjusting the electron transfer driving force.
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11. |
- Sun, S. G., et al.
(författare)
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Synthesis of two novel rhenium(I) bipyridyl photosensitive dyes
- 2004
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Ingår i: Chinese Chemical Letters. - 1001-8417 .- 1878-5964. ; 15:8, s. 965-968
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Tidskriftsartikel (refereegranskat)abstract
- Two novel rhenium(I) 2, 2'-bipyridyl complexes, [(4,4'-di-COOEt-bipy) Re(CO)3 (NCCH3)PF6] and [(4,4'-di-COOEt-bipy) Re (CO)(3) (NCS)], a model complex [(4,4'-di-COOEt-bipy) Re (CO)(3) (pyridine)PF6], were synthesized. Their ground state electronic spectra and emission spectra were measured in acetonitrile. The MLCT absorption maximum of the complex exhibited a considerable red shift as the ligand changed from pyridine to CNCH3, or SCN.
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12. |
- Talib, Shamraiz Hussain, et al.
(författare)
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CO oxidation on MXene (Mo2CS2) supported single-atom catalyst : A termolecular Eley-Rideal mechanism
- 2022
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Ingår i: Chinese Chemical Letters. - : Elsevier. - 1001-8417 .- 1878-5964. ; 34:2
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Tidskriftsartikel (refereegranskat)abstract
- Finding transition metal catalysts for effective catalytic conversion of CO to CO2 has attracted much attention. MXene as a new 2D layered material of early transition metal carbides, nitrides, and carbo-nitrides is a robust support for achoring metal atoms. In this study, the electronic structure, geometries, thermodynamic stability, and catalytic activity of MXene (Mo2CS2) supported single noble metal atoms (NM = Ru, Rh, Pd, Ir, Pt and Au) have been systematically examined using first-principles calculations and ab initio molecular dynamic (AIMD) simulations. First, AIMD simulations and phonon spectra demonstrate the dynamic and thermal stabilities of Mo2CS2 monolayer. Three likely reaction pathways, LangmuirHinshelwood (LH), Eley-Rideal (ER), and Termolecular Eley-Rideal (TER) for CO oxidation on the Ru1- and Ir1 @Mo2CS2 SACs, have been studied in detail. It is found that CO oxidation mainly proceeds via the TER mechanism under mild reaction conditions. The corresponding rate-determining steps are the dissociation of the intermediate (OCO-Ru1-OCO) and formation of OCO-Ir1-OCO intermediate. The downshift d-band center of Ru1- and Ir1@Mo2CS2 help to enhance activity and improve catalytst stability. Moreover, a microkinetic study predicts a maximum CO oxidation rate of 4.01 x 10 2 s-1 and 4.15 x 10 3 s-1 (298.15 K) following the TER pathway for the Ru1- and Ir1 @Mo2CS2 catalysts, respectively. This work provides guideline for fabricating and designing highly efficient SACs with superb catalyts using MXene materials.
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13. |
- Tang, Yunyu, et al.
(författare)
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Solar cells sensitized by porphyrin dyes containing a substituted carbazole donor with synergistically extended absorption and suppressed the dye aggregation
- 2020
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Ingår i: Chinese Chemical Letters. - : Elsevier BV. - 1001-8417 .- 1878-5964. ; 31:7, s. 1927-1930
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Tidskriftsartikel (refereegranskat)abstract
- To achieve high power conversion efficiencies (PCEs), three porphyrin sensitizers have been synthesized and explored to simultaneously enhance the photocurrent (Jsc) and photovoltage (Voc). On basis of the XW4, a benzothiadiazole (BTD) unit has been introduced to afford XW57 with the aim to extend the absorption wavelength and enhance the light harvesting ability. As a result, a Jsc of 13.72 mA/cm2 has been obtained for XW57, higher than that of XW4. On this basis, XW58 has been prepared by modifying the carbazole-based donor with two bulky dihexyloxyphenyl groups, and the superior anti-aggregation character raises the Voc from 781 mV (XW4) to 844 mV. When both the BTD unit and the bulky groups are introduced to the acceptor and donor units, respectively, the resulting sensitizer XW59 exhibits a highest PCE value of 7.34% with synergistically enhanced Jsc of 13.19 mA/cm2 and Voc of 793 mV. These results provide further insight into developing high performance dye-sensitized solar cells
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14. |
- Wang, Bo, et al.
(författare)
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Unprecedented differences in the diamond nucleation density between carbon- and silicon-faces of 4H-silicon carbides
- 2020
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Ingår i: Chinese Chemical Letters. - : ELSEVIER SCIENCE INC. - 1001-8417 .- 1878-5964. ; 31:7, s. 2013-2018
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Tidskriftsartikel (refereegranskat)abstract
- 4H-silicon carbides deposited by diamond films have wide applications in many fields such as semiconductor heterojunction, heat sink and mechanical sealing. Nucleation plays a critical role in the deposition of the diamond film on 4H-silicon carbides. Nevertheless, as a typical polar material, the fundamental mechanism of diamond nucleation on different faces of 4H-silicon carbides has not been fully understood yet. In this contribution, nucleation of diamond was performed on the carbon- and silicon-faces of 4H-silicon carbides in a direct current chemical vapor deposition device. The nucleation density on the carbon-face is higher by 2-3 orders of magnitude compared to the silicon-face. Transmission electron microscopy verifies that there are high density diamond nuclei on the interface between the carbon-face and the diamond film, which is different from columnar diamond growth structure on the silicon-face. Transition state theory calculation reveals that the unprecedented distinction of the nucleation density between the carbon-face and the silicon-face is attributed to different desorption rates of the absorbed hydrocarbon radicals. In addition, kinetic model simulations demonstrate that it is more difficult to form CH2(s)-CH2(s) dimers on silicon-faces than carbon-faces, resulting in much lower nucleation densities on silicon-faces. (C) 2019 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.
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15. |
- Wang, Qiang, et al.
(författare)
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Fluorine-containing agrochemicals in the last decade and approaches for fluorine incorporation
- 2022
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Ingår i: Chinese Chemical Letters. - : Elsevier BV. - 1001-8417 .- 1878-5964. ; 33:2, s. 626-642
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Tidskriftsartikel (refereegranskat)abstract
- In this review, the methodologies for fluorine incorporation of 40 fluorine-containing agrochemicals that received an international standardization organization (ISO) name during the last decade are described. The predominant approach for fluorine introduction of these agrochemicals is to use a fluorine-containing building block. Here we present how the fluorine-containing building blocks are introduced into these agrochemicals. The synthetic methods of fluorine-containing building blocks that are not easily available are also specifically discussed. Fluoroarenes, difluomethylarenes and trifluomethylarenes are the main building blocks that have been used in this review. Fluorine-containing small molecules, such as alcohol, amine, ketoester, olefin are also widely used. The only example of late-stage fluorination is the synthesis of fungicide quinofumelin. We believe the fluorine introduction methods described here can provide ideas for the development of new and economical pesticide synthetic routes, and stimulate researchers to develop new fluorine incorporation methods and create new pesticides.
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16. |
- Wang, Qiang, et al.
(författare)
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Studies on the biological activity of gem-difluorinated 3,3'-spirocyclic indole derivatives
- 2022
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Ingår i: Chinese Chemical Letters. - : Elsevier BV. - 1001-8417 .- 1878-5964. ; 33:2, s. 859-862
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Tidskriftsartikel (refereegranskat)abstract
- The biological activities of a series of 3,3′-spirocyclic indole derivatives containing CF2, phosphine oxide, indole, and cyano functional groups were evaluated, and these derivatives were found to exhibit anti-TMV, fungicidal, and insecticidal activities.
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17. |
- Wu, Yun, et al.
(författare)
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Effect of dihedral angle of bridge unit on the performance of dye-sensitized solar cell
- 2016
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Ingår i: Chinese Chemical Letters. - : Elsevier BV. - 1001-8417 .- 1878-5964. ; 27:6, s. 927-932
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we investigated the impact of bridge unit on their photo-physical and photovoltaic performance. Increased planarity of the dyes effectively extended the absorption, but reduces the efficiency. Interestingly we found that dyes with a thiophene conjugate unit showed inferior performance when compared with benzene. Theoretical computation indicates a large dihedral angle in the latter system. EIS analysis evidenced the severe recombination in the thiophene-based dye, showing that good planarity may lead to dye aggregation and decrease the efficiency.
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18. |
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19. |
- Zhang, Jun, et al.
(författare)
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Stereochemical editing : Catalytic racemization of secondary alcohols and amines
- 2024
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Ingår i: Chinese Chemical Letters. - 1001-8417 .- 1878-5964. ; 35:5
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Tidskriftsartikel (refereegranskat)abstract
- Chiral alcohols and amines are important structural units widely existing in pharmaceuticals, agrochemicals, and food additives. Dynamic kinetic resolution (DKR) is an efficient strategy to deliver optically active alcohols and amines from their racemates. For the development of DKR method, racemization catalyst plays as a crucial element with the requirement of compatibility with the kinetic resolution (KR) system. In this paper, recent advance in the catalytic racemization of secondary alcohols and amines is summarized based on different types of racemizing intermediates, which are redox racemization via ketone/imine intermediates, racemization via radical intermediates, and racemization via carbocation intermediates. Enzymatic racemization of secondary alcohols and amines is also enclosed. (c) 2024 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.
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20. |
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