查找使用阿拉丁产品的科研文献

Effect of Zn2+ and F− Co-Modification on the Structure and Electrochemical Performance of Li4Ti5O12 Anode Material

Aijia Wei,Wen Li,Lihui Zhang,Xiaohui Li,Xue Bai,Zhenfa Liu

Zn 2 + and F − ions are successfully used to modify pure Li 4 Ti 5 O 1 2 via a co-precipitation method followed by calcination at 400 ∘ C for 5 h in an Ar atmosphere in order to further investigate the reaction mechanism of the fluoride modification process. Zn 2 + and F − co-modified Li 4 Ti 5 O 1 2 samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and electrochemical measurements. After the modification process, no ZnF 2 coating layer is formed on the surface of Li 4 Ti 5 O 1 2 , instead, F − ions react with Li 4 Ti 5 O 1 2 to generate a new phase, composed of a small amount of anatase TiO 2 , rutile TiO 2 , LiF, and Zn 2 + ions are suspected to form a ZnO coating layer on Li 4 Ti 5 O 1 2 particles. The electrolyte reduction decomposition is suppressed in Zn 2 + and F − co-modified Li 4 Ti 5 O 1 2 due to the ZnO coating layer. 1 wt.% Zn 2 + and F − co-modified Li 4 Ti 5 O 1 2 exhibits the best rate capability, which leads to a charge capacity of 236.7, 227.8, 222.1, 202.7, 188.9 and 150.7 mAh g − 1 at 0.2C, 0.5C, 1C, 3C, 5C and 10C, respectively, between 0 V and 3 V. Furthermore, 1 wt.% Zn 2 + and F − co-modified Li 4 Ti 5 O 1 2 exhibits 96.0% charge capacity retention at 3C rate after 200 cycles, which is significantly higher than that of pure Li 4 Ti 5 O 1 2 (78.4%).

Anionic F-doping-induced engineering of P2-type layered cathode materials for high-performance potassium-ion batteries

Yurong Wu,Ziyun Zhang,Jiangshan Huo,Runguo Zheng,Zhishuang Song,Zhiyuan Wang,Yanguo Liu,Dan Wang

P2-type layered oxides have emerged as promising cathode candidate materials for potassium-ion batteries. Nevertheless, unsatisfactory cycling stability hinders their practical application, chiefly arising from deleterious phase transitions and the Jahn–Teller distortion of Mn3+. Herein, an anion-doping strategy where F− is incorporated into P2-K0.6Zn0.1Ti0.05Al0.05Mn0.8O2 (KTMO) cathode materials is proposed. Raman spectroscopy was employed to investigate the local chemical environment of these materials. The results revealed a slight shift to higher wavenumbers in the Eg and A1g peaks, which was ascribed to the shortening of the average TM–O bond length triggered by the addition of F. Ex situ XRD analysis revealed that the material K0.6Zn0.1Ti0.05Al0.05Mn0.8O1.93F0.07 effectively suppresses undesirable phase transitions. Moreover, the maximum variation in the lattice parameter c is only 2.2% during potassium insertion/extraction, which fully demonstrates the outstanding performance of this material in terms of structural stability. This strategy brings about excellent cycling stability with a reversible capacity of 131.8 mA h g−1 and capacity retention of 76.8% after 100 cycles, within a voltage range of 2.0–4.0 V. These findings offer novel insights into the design of cathode materials possessing optimized structures and enhanced performance for potassium-ion batteries.

Preparation and selective adsorption performance of F-modified ZSM-5 zeolite for m-cresol and p-cresol

Xudong Wang,Yanyang Wu,Tianyou Wang,Bin Wu,Kui Chen,Lijun Ji

M-cresol and p-cresol, typically produced as mixtures in industrial processes, are crucial chemical intermediates. However, their separation is challenging due to their similar structures and properties. ZSM-5 zeolite has shown potential as an adsorbent for separation, while the performance is yet to be improved. In this study, ZSM-5-F(x) was synthesized via hydrothermal method, incorporating F − ions during the synthesis process. The adsorption behaviour of m-cresol and p-cresol on ZSM-5-F(x) was investigated through static experiments, with ZSM-5-F(8) demonstrating the highest selectivity (9.01). Both ZSM-5-F(0) and ZSM-5-F(8) were characterized using XRD, scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) techniques. In addition, the introduction of F − ions increased the material's electronegativity, as demonstrated by the change in zeta potential from 53.22 to −45.93 mV. Single-component adsorption of m-cresol or p-cresol on ZSM-5-F(0) and ZSM-5-F(8) respectively were investigated in detail. The adsorption of m-cresol on ZSM-5-F(8) showed a non-monotonic phenomenon with a significant decrease after 0.06 mol/L. The thermodynamic parameters including Δ G , Δ H , and Δ S were calculated accordingly. All the values |Δ G |, |Δ H |, and |Δ S | of both components on ZSM-5-F(8) were greater than those on ZSM-5-F(0), suggesting that the introduction of F − ions facilitated the adsorption. Competitive adsorption experiments on both ZSM-5-F(0) and ZSM-5-F(8) were conducted at 298.2 K. The results indicated that the selectivity α p/m on ZSM-5-F(8) increased with increasing initial concentration and laid between 13 and 14. After seven consecutive regeneration cycles, the selectivity (α p/m ) only decreased to 13. This study suggests that ZSM-5-F(8) could be a promising adsorbent for m-cresol and p-cresol in industrial applications.

Fabrication of N and F Modified La-TiO2 Nanoparticles and Their Enhanced Photocatalytic Response to Visible Light

Fan Ji-Min,Lei Yun-Yu,Gu Zhan-Yong,Zhang Bing,Yin Shu,Zhao Zhi-Huan

N and F co-doped La-TiO2 (La-TONF) samples were prepared through the solvothermal method by using HMT and NaF as precursors. The obtained samples were characterized by UV-Vis DRS, XRD, XPS and PL measurements for light-harvesting properties, crystal phase and optical characteristics, respectively. Interestingly, the TONF sample had a different fluorescence emission intensity than the TON or TOF samples, thus suggesting a clear synergistic effect of N and F co-doping. The optimal doping amount of La was 2 wt.%, and the absorption edge was red-shifted from 453 nm to 464 nm for La-TiO2 and La-TONF. The photocatalytic activity was evaluated by degradation of MO and oxidation of TMB under visible light irradiation. La-TONF exhibited excellent photocatalytic activity and a degradation rate of 92.4%, 4.4 times that of undoped TiO2 (20.8%). The photocatalytic degradation activity remained above 85.8%, even after five runs. In addition, the MO photodegradation catalyzed by La-TONF followed first order kinetics. According these results, a possible synergistic effect mechanism for the enhanced photocatalytic performance is proposed.

Polymorphism in F pocket affects peptide selection and stability of type 1 diabetes-associated HLA-B39 allotypes

A. W. Peshala Amarajeewa,Aslihan Özcan,Alveena Mukhtiar,Xu Ren,Qianyu Wang,Pemra Ozbek,Malgorzata A. Garstka,Onur Serçinoğlu

HLA-B*39:06, HLA-B*39:01, and HLA-B*38:01 are closely related HLA allotypes differentially associated with type 1 diabetes (T1D) risk and progression. B*39:06 is highly predisposing, while B*39:01 and B*38:01 are weakly predisposing and protective allotypes, respectively. Here, we aimed to decipher molecular mechanisms underlying the differential association of these allotypes with T1D pathogenesis. We addressed peptide binding and conformational stability of HLA-B allotypes using computational and experimental approaches. Computationally, we found that B*39:06 and B*39:01 allotypes had more rigid peptide-binding grooves and were more promiscuous in binding peptides than B*38:01. Peptidomes of B*39:06 and B*39:01 contained fewer strong binders and were of lower affinity than that of B*38:01. Experimentally, we demonstrated that B*39:06 and B*39:01 had a higher capacity to bind peptides and exit to the cell surface but lower surface levels and were degraded faster than B*38:01. In summary, we propose that promiscuous B*39:06 and B*39:01 may bind suboptimal peptides and transport them the cell surface, where such unstable complexes may contribute to the pathogenesis of T1D.

F-Doped CoFe Bimetallic Heterostructure Electrocatalyst with Ultra-Low Impedance for High-Current-Density Alkaline Hydrogen Evolution

Qian Kong,Chengcheng Yu,Qing Lu,Xingyu Yang,Tongguang Xu,Qi Song,Huatong Li,Zhaoshuo Yuan,Hongyu Liu,Qian Qiao,Gang He,Yufan Wang,Linglong Yao,Xiaoping Dai,Xin Zhang

The electrolysis of water for hydrogen production has gained increasing attention as a sustainable and efficient method to obtain high-purity green hydrogen. The development of efficient catalysts for hydrogen evolution is crucial in order to achieve this target under industrial conditions. The objective of this work is to synthesize a highly efficient F-Co x Fe y (PO n ) z /IF catalyst with ultra-low impedance for hydrogen evolution in electrolytic water by incorporating metal phosphatides into metal oxide nanoclusters through a controlled two-step process involving melting and electrodeposition. The nano-heterostructure of F-Co x Fe y (PO n ) z /IF exhibits a low overpotential of 276 mV at a current density of 1000 mA cm −1 , while having an electrochemical impedance comparable to commercial Pt/C/CP (0.41 Ω), and long-term stability up to 200 h in 1 M KOH electrolyte. The synergistic effect of crystal/amorphous heterojunctions, F doping, and oxygen vacancies further enhances the kinetics of water cracking. Impressively, when combined with NiFeCo LDH/NiS/NF as membrane electrodes, F-Co x Fe y (PO n ) z /IF || NiFeCo LDH/NiS/NF achieves a water decomposition voltage of 2.03 V at a current density of 1000 mA cm −2 and demonstrates stable operation for over 500 h, showing great potential for large-scale commercial production.

Effects of Vitamin B12 on the Reductive Transformation of PFOS and F-53B by Nanoscale Zero-Valent Zinc

Perfluorooctane sulfonate (PFOS) and 6:2 chlorinated polyfluoroalkyl ether sulfonate (F-53B) are persistent per- and polyfluoroalkyl substances of concern in aquatic environments. This study compared their anaerobic reductive transformation by nanoscale zero-valent zinc (nZn0), with and without vitamin B12 (VB12). Solutions containing 1 mg/L PFOS or F-53B were treated with nZn0(278 mg/L) and, where indicated, 0.05 mmol/L VB12 (67.8 mg/L) at pH 8.5 and 30 °C for 20 days. After correction for losses observed in reagent-free blanks, PFOS loss was negligible with nZn0alone but reached approximately 34% with nZn0+ VB12, and the corresponding defluorination rate was 33.9%. In contrast, F-53B showed approximately 85% blank-corrected loss by day 6 with either nZn0alone or nZn0+ VB12, while defluorination rates reached 38.0% and 30.7%, respectively, indicating no enhancing benefit of VB12 for F-53B under the studied conditions. Nominal-mass LC-MS/MS features consistent with partially defluorinated and hydrogen-substituted products were observed, and tentative transformation pathways were proposed. These results demonstrated compound-specific effects of VB12 and emphasized the distinction among loss, transformation and defluorination when evaluating PFAS destruction.

Enabling Sensitive and Stable X-ray Detection in a 2D Trilayered Hybrid Perovskite with Strong F–π Interactions

Peixuan Zhu,Huawei Yang,Lemei Long,Panpan Yu,Chengmin Ji,Zeng-Kui Zhu,Ying Zeng,Shihai You,Junhua Luo

Organic–inorganic hybrid perovskites integrate the advantages of organic and inorganic components, making them promising candidates for high-performance X-ray detection. However, severe ion migration under external voltage makes it a tough challenge to realize high sensitivity and operational stability simultaneously in practical application. Here, we report a two-dimensional (2D) trilayered hybrid perovskite with F-substituted aromatic spacers, (FBZA)2(MA)2Pb3Br10 (1, FBZA = 4-fluorobenzylamine, MA = methylamine). The thick inorganic slabs endow 1 with efficient carrier transport paths, achieving a superior mobility-lifetime product of 1.3 × 10–3 cm2 V–1, much higher than most of 2D perovskites. Indeed, a high sensitivity of 2818.2 μC Gy-1 cm–2 and a low detection of limit (LOD) of 43.7 nGy s–1, as well as a low dark current drift of 1.61 × 10–7 nA cm–1 s–1 V–1 under a bias of 100 V, suggests its great potential on sensitive and stable X-ray detection. The stable and reliable response to long-time X-ray irradiation of high dose rate under large working voltage further verifies its operational stability. This research develops a multilayered 2D perovskite with strong interlayer interactions, successfully achieving high-sensitivity and high-stability X-ray detection, which sheds light on the design and construction of high-performance perovskite-based X-ray detectors in the future.

B, F Co-doping flexible carbon nanofibers as a fast and stable anode for potassium-ion hybrid capacitor

Zuocheng Luo,Qingfeng Zhang,Wei Xie,Tong Yuan,Qisheng Zang,Ning Wang,Hanxiao Fan,Shuhong Xie,Xiaoping Ouyang

Potassium ion hybrid capacitors (PIHCs) have attracted widespread attention as combining the advantages of potassium ion batteries (PIBs) with supercapacitors . However, the sluggish kinetics caused by the large radius of K + hinder the practical application of PIHCs. Herein, we synthesized a boron and fluorine co-doping interlaced network porous carbon nanofibers (BF-PCNFs), which was used as the freestanding anode of PIHCs the freestanding anode of PIHCs to alleviate large volume expansion and increase conductivity. Benefiting from the B, F co-doping and porous interlace nanostructure of BF-PCNFs, the anode shows 185 mA h g −1 under a load of 12.6 mg cm −2 , a reversible capacity of 176 mA h g −1 at 1000 mA g −1 after 6000 cycles, and the capacity retention from 100 mA g −1 to 5000 mA g −1 is 62%. Furthermore, the PIHCs based on BF-PCNFs as anode and activated carbon as cathode exhibit an energy density of 87 Wh kg −1 and a power density of 393 W kg −1 . The capacity retention is as high as 78% over 4000 cycles. Considering the exceptional rate performance, long cyclability and high-mass-loading, our work may supply a new strategy for designing novel energy storage devices with outstanding performance.

Ni and F co-modification to enhance the electrochemical properties of Li4Ti5O12 anode materials for lithium-ion batteries

Zhai Huanhuan,Shuai Yi,Wang Yu,Chen Kanghua

As a negative electrode material, the main drawbacks of Li 4 Ti 5 O 12 (LTO) are its low electric conductivity and poor Li-ion diffusion coefficient. Fortunately, elements modification to address these problems is an effective method. Herein, we firstly report Ni and F co-modified LTO material which is synthesized via a solid-state reaction. Powder X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy were conducted to investigate the structure and morphology. Afterwards, we surprisingly find that Ni and F co-modification can reduce the overall charge transfer resistance of LTO for part of Ti 4+ converts into Ti 3+ and Ni 2+ ions supply the charge carriers. When test in battery, a superior discharge capacity of 236.1 mAh g −1 at 0.036 A g −1 is obtained, much higher than that of pristine LTO (196.9 mAh g −1 ). Furthermore, it still retains a discharge capacity of 174.6 mAh g −1 after 200 cycles at 0.18 A g −1 and exhibits an excellent rate performance.

Relation of thickness and luminescence in F-modified silicate based remote phosphor coating for white light emitting diodes

Li Rui,Wang Yan-ze,Mao Zhi-yong,Wang Da-Jian

A remote phosphor coating by using Sr 3 (Al,Si)(O, F) 5 :Ce 3+ (SASF:Ce 3+ ) on glass substrate was prepared by a simple and convenient screen printing method. The crystalline phase and the distribution of SASF:Ce 3+ crystals in coating were investigated by XRD and SEM, respectively. The scattering light and absorption light properties of remote phosphor coating with different thicknesses were discussed through Lambert–Beer’s law. The relationship between luminous efficiency and absorption coefficient was demonstrated. White light emitting diode prototype fabricated with blue chip and the prepared patterned SASF:Ce 3+ remote phosphor in this work showed excellent performances, opening a cost-effective process to generate planar white light.

A Large Family of Centrosymmetric and Chiral f-Element-Bearing Iodate Selenates Exhibiting Coordination Number and Dimensional Reductions

Meiying Qie,Jian Lin,Fang Kong,Mark A. Silver,Zenghui Yue,Xiaomei Wang,Linjuan Zhang,Hongliang Bao,Thomas E. Albrecht-Schmitt,Jian-Qiang Wang

The exploration of phase formation in the f-element-bearing iodate selenate system has resulted in 14 novel rare-earth-containing iodate selenates, Ln(IO3)(SeO4) (Ln = La, Ce, Pr, Nd; LnISeO-1), Ln(IO3)(SeO4)(H2O) (Ln = Sm, Eu; LnISeO-2), and Ln(IO3)(SeO4)(H2O)2·H2O (Ln = Gd, Dy, Ho, Er, Tm, Yb, Lu, Y; LnISeO-3), as well as two new thorium iodate selenates, Th(OH)(IO3)(SeO4)(H2O) (ThISeO-1) and Th(IO3)2(SeO4) (ThISeO-2). LnISeO-3 and ThISeO-2 crystallize in the chiral space group P212121, while LnISeO-1, LnISeO-2, and ThISeO-1 crystallize in the centrosymmetric space group P21/c. The numbers of both coordinating and hydrating water molecules crystallized in LnISeO-1, LnISeO-2, and LnISeO-3 increase along these three series, in line with the increasingly negative values of hydration enthalpies of heavier trivalent lanthanide ions. Such a systematic change in compositions, especially the first coordination sphere of Ln, further induces structural rearrangements, including coordination number and dimensional reductions. More specifically, the structures of LnISeO-1, LnISeO-2, and LnISeO-3 have undergone transitions from 2D Ln–oxo layers with 10-coordinate Ln centers to 1D Ln–oxo chains with 9-coordinate Ln centers and then to 0D Ln–oxo monomers with 8-coordinate Ln centers, respectively. The formation and characterization of this large family of Ln/Th iodate selenates suggest that such a mixed-anion system not only exhibits richer structural chemistry but also can be capable of generating intriguing properties, such as the second-harmonic generation (SHG) effect.