CHEMISTRY OF MATERIALS
·
2023
·
IF 8.6
Mengran Sun,Wenhao Xing,Shyong K. Chen,Chunxiao Li,Wenhao Liu,Ming-Hsien Lee,Jiyong Yao
Chalcogenides are promising candidates for exploring mid- and far-infrared nonlinear optical (NLO) materials. Nevertheless, although tellurides possess greater advantages in the above-mentioned spectral regions, the reports on telluride NLO materials are far fewer than those on sulfides and selenides. In this work, a new quaternary NLO-active telluride, KCd4Ga5Te12, was discovered, and its Rb and Cs analogues were successfully synthesized. They are crystallized in the trigonal R3 space group and the structure features a 3D diamond-like framework constructed by vertex-sharing asymmetric MTe4 tetrahedra (centered by disordered Cd and Ga) that are stacked along the c-axis. Moreover, a comprehensive study of their IR NLO properties, photoluminescence properties, and structural features was performed. These compounds exhibited large powder second-harmonic generation (SHG) intensities, about 2.1 (2.7, 4.4) times that of AgGaSe2 in the particle size range of 20–50 (125–150) μm and a wide transmission range (∼25 μm). The SHG-density analysis revealed that the largest component χ333(2) of KCd4Ga5Te12 originates from three types of Te in the crystal structure. More importantly, it is rare in literature to demonstrate the consistency of linear and NLO properties calculated using both ultrasoft pseudopotentials and norm-conservation pseudopotentials. Besides, the title compounds also exhibit strong luminescence emissions around 420 and 470 nm at 298 K. This work implies that title compounds are promising candidates in the IR NLO applications.
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BIOMACROMOLECULES
·
2022
·
IF 6.978
Fei Fu,Minggui Shen,Dan Wang,He Liu,Shibin Shang,Fei-Long Hu,Zhanqian Song,Jie Song
Low-k dielectrics are urgently needed in modern integrated circuits. The introduction of free volume instead of porous structures has become a powerful strategy to reduce the k value. According to this strategy, the biomass resource rosin-containing hydrogenated phenanthrene ring was introduced into benzocyclobutene (BCB) resin to reduce the k value; then a rosin-based BCB monomer was successfully synthesized. Meanwhile, the BCB monomer without a rosin skeleton was prepared. After converting the monomers into thermo-crosslinked materials, notably that the rosin skeleton has a great influence on the free volume and k value of the material. The fractional free volume and k value of the former are 26% and 2.44, respectively, and those of the latter are 14% and 2.84, respectively. In addition, the distances between molecular chains and the density of the former are 0.60 nm and 1.06 g cm–3, respectively; those of the latter are 0.56 nm and 1.28 g cm–3, respectively. These data show that introducing hydrogenated phenanthrene rings occupies part of the space and hinders the packing of molecular chains, which increases the distance between molecular chains and reduces the density of the polymer, resulting in an increasing free volume and a reducing k value. Notably that introducing hydrogenated phenanthrene rings cannot affect other properties of the material. Therefore, this research indicates that introducing rosin skeletons can prepare high-performance materials, which provide some promising low-k materials for the development of electronics and microelectronics.
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Inorganic Chemistry Frontiers
·
2022
·Vol. 9
·期 5
·950-958
·
IF 7.779
Shifei Kang,Zhihao Zhang,Maofen He,Zirou Fang,Di Sun,Lulu Zheng,Xijiang Chang,Lifeng Cui
Co-modification of graphitic carbon nitride (g-C3N4) photocatalysts can maximally optimize their intrinsic photoelectric structures, but usually involves complex multistep reactions, and thus is challenging because structural collapse and active site decay usually happen due to the complex process, over-treatment or conflict of different modification strategies. In this work, potassium iodate (KIO3), an edible salt additive, was used as a critical waste-free modifier in the thermal polymerization of g-C3N4, leading to a fast and coordinated co-modification of g-C3N4 photocatalysts. The final g-CN-KIO3 photocatalyst demonstrated a superior and balanced optical absorption ability and semiconductor band structure. In visible-light-driven photocatalytic model tests, g-CN-KIO3 showed a 3.25 times higher Cr(VI) photoreduction rate and five orders of magnitude lower residual bacteria in a photocatalytic sterilization within 120 min compared with raw g-C3N4. The photocatalytic performance of g-CN-KIO3 also outperformed all of the controls without maximized K–I–O co-modification (CN-K, CN-I, CN-O, and CN-KI). Photocurrent and electrochemical impedance experiments suggest that the co-modified photocatalysts have a faster charge separation ability, which is attributed to the multiple K–I–O co-modifications inducing an optimized surface electronic structure and slower carrier recombination. This work provides a new way to simplify and coordinate complex multi-factor regulation of materials.
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Antibiotics-Basel
·
2022
·Vol. 11
·期 2
·162
·
IF 5.222
Xia Xiao,Quanmin Huan,Yanhu Huang,Yuan Liu,Ruichao Li,Xilan Xu,Zhiqiang Wang
Tigecycline (TIG) is one of the last effective options against multidrug resistance bacteria. Recently, the RND (resistance–nodulation–division) efflux pump gene cluster,tmexCD1-toprJ1, and the tetracycline-efflux pumptet(A) mutation were reported to mediate high level resistance to TIG in clinically important pathogens, weakening the efficacy of TIG. In this study, we report the potent synergistic effect of the antidiabetic drug metformin in combination with TIG againsttet(A) mutant andtmexCD1-toprJ1positiveK. pneumoniae. The fractional inhibitory concentration index (FICI) of TIG and metformin were less than 0.05 for all the tested isolates. The time–kill curve assay showed that the combination of TIG and metformin exhibited much better antimicrobial effect than TIG alone. The synergistic effect was also confirmed in vivo using a well-studiedGalleria mellonellalarvae model. Mechanistic studies demonstrated that metformin disrupted the important component of proton motive force, the electric potential (Δψ) and the function of efflux pump, thereby increasing the intracellular concentration of TIG. This finding revealed that metformin might be a possible adjuvant of TIG for combating with superbugs carrying thetet(A) mutant andtmexCD1-toprJ1genes.Keywords:tigcycline;metformin;tmexCD1-toprJ1;tet(A);synergy
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Nan Xin,Yifei Li,Guihua Tang,Longyun Shen
High-efficient and environment-friendly thermoelectric materials have attracted much attention. The single crystal tin selenide (SnSe) has a record high thermoelectric figure of merit ( ZT ) of 2.6 at ~800 K. Polycrystalline SnSe has better mechanical-strength but inferior ZT values than the single crystal, attribute to the paradoxically higher thermal conductivity ( κ ). In this work, we synthesized K x Sn 1−x Se (x = 0, 0.01, 0.02, 0.03 and 0.04) by doping K 2 CO 3 . A large number of point defects and dislocations generated with CO 2 volatilization, which possibly reduces κ . Based on this process, the K x Sn 1−x Se powders were followed by the hydrogen reduction with 4% H 2 − 96% Ar atmosphere to reduce tin oxide and potassium oxide which have high κ . These strategies lead to an ultra-low κ 0.32 Wm −1 K −1 in K 0.03 Sn 0.97 Se at 798 K. The effects of K doping on electronic transport performance of SnSe were studied by density functional theory calculation and experimental measurement. Doing K can narrow the band gap, increase hole concentration and enhance the electrical conductivity ( σ ) of SnSe. At 298 K, the σ of K x Sn 1−x Se increased by more than 2.5 times compared with the pristine SnSe. In high temperature region (623 K< T < 823 K), the σ is mainly affected by thermal excitation. High doping level of K (x = 0.03 and 0.04) suppresses the thermal excitation and limits the maximum of ZT . As the result, A high ZT of 1.06 is obtained at 798 K from K 0.01 Sn 0.99 Se perpendicular to the pressing direction, which is 103.8% larger than that of pristine SnSe. In addition, the hot-pressing polycrystalline K x Sn 1−x Se remains obvious lamellar morphology and show anisotropy. The σ and κ of K x Sn 1−x Se samples perpendicular to the pressure direction are much higher than those of the samples parallel to the pressure direction. This anisotropy decreases with the increasing K content.
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ANALYTICAL CHEMISTRY
·
2021
·
IF 6.986
Xiao-Qiong Li,Xiang-Nan Liu,Yi-Lei Jia,Xi-Liang Luo,Hong-Yuan Chen,Jing-Juan Xu
Lysosomal acidification is essential for its degradative function, and the flux of H+ correlated with that of K+ in lysosomes. However, there is little research on their correlation due to the lack of probes that can simultaneously image these two ions. To deeply understand the role of K+ in lysosomal acidification, here, we designed and fabricated a nanodevice using a K+-aptamer and two pH-triggered nanoswitches incorporated into a DNA triangular prism (DTP) as a dual signal response platform to simultaneously visualize K+ and pH in lysosomes by a fluorescence method. This strategy could conveniently integrate two signal recognition modules into one probe, so as to achieve the goal of sensitive detection of two kinds of signals in the same time and space, which is suitable for the detection of various signals with the correlation of concentration. By co-imaging both K+ and H+ in lysosomes, we found that the efflux of K+ was accompanied by a decrease of pH, which is of great value in understanding lysosomal acidification. Moreover, this strategy also has broad prospects as a versatile optical sensing platform for multiplexed analysis of other biomolecules in living cells.
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ACS Nano
·
2023
·
IF 17.1
Shiyong Chu,Caoyang Shao,Jiaming Tian,Jingyang Wang,Yuan Rao,Chengrong Xu,Haoshen Zhou,Shaohua Guo
Layered oxides are widely accepted to be promising cathode candidate materials for K-ion batteries (KIBs) in terms of their rich raw materials and low price, while their further applications are restricted by sluggish kinetics and poor structural stability. Here, the high-entropy design concept is introduced into layered KIB cathodes to address the above issues, and an example of high-entropy layered K0.45Mn0.60Ni0.075Fe0.075Co0.075Ti0.10Cu0.05Mg0.025O2 (HE-KMO) is successfully prepared. Benefiting from the high-entropy oxide with multielement doping, the developed HE-KMO exhibits half-metallic oxide features with a narrow bandgap of 0.19 eV. Increased entropy can also reduce the surface energy of the {010} active facets, resulting in about 2.6 times more exposure of the {010} active facets of HE-KMO than the low-entropy K0.45MnO2 (KMO). Both can effectively improve the kinetics in terms of electron conduction and K+ diffusion. Furthermore, high entropy can inhibit space charge ordering during K+ (de)insertion, and the transition metal–oxygen covalent interaction of HE-KMO is also enhanced, leading to suppressed phase transition of HE-KMO in 1.5–4.2 V and better electrochemical stability of HE-KMO (average capacity drop of 0.20%, 200 cycles) than the low-entropy KMO (average capacity drop of 0.41%, 200 cycles) in the wide voltage window.
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ACS Applied Nano Materials
·
2026
·
IF 5.8
Chenglin Wang,Yibo Wang,Hanyang Li,Gaozhao Chen,He Liu,Wentao Hao,Fazl Ullah,Qiuyun Ouyang
Abstract To address intrinsic parity-forbidden transitions, strong electron-phonon coupling, and defect-assisted nonradiative recombination in Cs2NaInCl6 nanocrystals, K-doped Cs2NaInCl6:xK+ (x = 0−1) nanocrystal powders were synthesized via a hot-injection method. The powders were dispersed in methyl methacrylate to prepare organic glasses. The x = 0.2 sample exhibits the best performance. Nonlinear absorption was evaluated by open-aperture Z-scan measurements. Both undoped and K+-doped nanocrystals exhibit a transition from saturable absorption to reverse saturable absorption with increasing excitation energy. K+ doping significantly enhances the nonlinear absorption response. At 50 μJ, the nonlinear absorption coefficient of the K+-doped nanocrystals reaches 40 cm·GW−1, approximately 4.2 times that of the undoped nanocrystals (9.5 cm·GW−1). Meanwhile, the optical limiting threshold decreases from 4.69 to 3.53 J·cm−2. This enhancement is attributed to reduced nonradiative loss and prolonged excited-state lifetime induced by K+ incorporation, thereby facilitating carrier accumulation and strengthening excited-state absorption. In addition, the (Cs2NaInCl6:0.2K+)6/poly(methyl methacrylate) organic glass retains 97.14% of its initial nonlinear absorption response after five months. These results demonstrate that K+ doping is an effective strategy for regulating the nonlinear absorption performance of lead-free double perovskites and provide insights into the design of high-performance optical limiting and laser protection materials.
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APPLIED ENERGY
·
2023
·
IF 11.2
Juan Yi,Zhiwei Ye,Shixian Zhang,Yiheng Song,Zhilong Cao,Bin Liu,Chenjian Li,Shuang Liu,Shuai Nie,Chuanxi Xiong
Piezoelectric nanogenerators (PENGs) are mushrooming owing to demand of swift transformation of power supply from fossil fuel to green energy. Piezoelectric ceramics are enthusiastically chased because glorious PENGs demand for high piezoelectricity. Generally, brittleness of ceramics can be compensated by polymer, while the dielectric mismatch between low permittivity of polymer and high permittivity of ceramics plaguing researchers so long. Traditional contact poling is always interrupted by abrupt dielectric breakdown due to electric field concentration at interface between polymer and fillers. Here, we propose a strategy of using corona polarization instead of traditional contact polarization to insistently polarize large-area polymer composite films with high-k filler. The corona polarization technique can ignore the negative effect of local short circuit on polarization failure owing to prominent lateral insulation between deposited charges on surface of composites film, consequently obtaining well-performed piezoelectricity. Henceforth, polarization failure did not occur using corona even under poling voltage of 26 kV. The corona-poled PVDF/Y-ZnO PENG with only 15 wt% content of fillers generated output power density of ∼1064 μW/cm 3 . Our work will pilot the development of polymer composites with high-k filler and piezoelectric nanogenerators.
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FUEL
·
2020
·
IF 5.578
Hongliang Li,Hua Han,Yue Wang,Xianshu Dong,Hongli Yang,Minqiang Fan,Yang Hu,Zeyu Feng
In coal beneficiation, the clean coal would be easily contaminated with the super fine montmorillonite particles coating on it. This interaction between coal (hydrophobic) and montmorillonite (hydrophilic) surfaces is the interactions between the asymmetric systems. Previous studies detected the force between the montmorillonite and graphite or between the montmorillonite mounted tip and coal substrate to represent the interactions between 001 surface and coal. However, there is still lack of experimental direct measurement on the interaction between montmorillonite 001 surface and coal macerals. In this study, proposes methods for determinine the interactions between coal macerals and 001 surface of Na-, K- and Ca- montmorillonite directly by using an atomic force microscope (AFM). The results indicate that the 001 surface of Na- and Ca- montmorillonite served as the chaotropic and kosmotropic surface when it is adjacent to coal surfaces, with an attractive force and repulsive force occurring between them, respectively. The 001 surface of K-montmorillonite served as the chaotropic surface and kosmotropic surface while it is close to liptinite and inertinite, respectively. This chaotropic or kosmotropic property of the surface is determined by the coordination number of the cations and wettability of the hydrophobic surface simultaneously.
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JOURNAL OF POLYMER RESEARCH
·
2020
·Vol. 27
·期 11
·1-8
·
IF 2.426
Wang Qi,Pu Zejun,Zheng Xiaoyi,Tian Yuhan,Li Xinyue,Zhong Jiachun
Polyarylene ether nitrile (PEN) random copolymers were prepared from 6AF, BHPF, and 2, 6-dichlorobenzonitrile according to the nucleophilic aromatic substitution polymerization. The chemical structure of PEN random copolymers was characterized by the FT-IR and 1 H-NMR spectrum, respectively. The thermal properties of the PEN random copolymers were investigated by using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The resulting PEN copolymers have excellent thermal stability with high glass transition temperature ( T g ) ranging from 187℃ to 271℃ and the 5% weight loss temperature ( T 5% ) of PEN copolymers greater than 490℃ in nitrogen atmospheres. Meanwhile, the PEN films have excellent mechanical property, the tensile strength ranges from 55 to 95 MPa. Moreover, the dielectric properties of the PEN random copolymers were investigated by dielectric tests. The dielectric constants ( k ) and loss tangent (tan δ) of PEN (PEN-6-AF/BHPF100) film is only 2.3 and 0.03 at 1 kHz, respectively. More importantly, the dielectric properties were found to be relatively stable until the T g , which can be attributed to the existence of BHPF units in the molecular backbone.
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FUEL
·
2020
·
IF 5.578
Long Ma,Shuzhen Chen,Changlei Qin,Susu Chen,Weiyang Yuan,Xu Zhou,Jingyu Ran
Li 4 SiO 4 is a well-acknowledged CO 2 sorbent in the sorption-enhanced reforming system for low-cost H 2 production with a high purity. However, the inevitable presence of H 2 S in the biomass-derived syngas etc. could possibly affect the in-situ CO 2 adsorption significantly, which is important but has never been reported. In this work, the adsorption of CO 2 using Li 4 SiO 4 was investigated under varying H 2 S concentrations and reaction temperatures, and a series of characterization techniques were utilized to understand the effect of H 2 S and its action mechanism. The results show that the presence of H 2 S causes a rapid loss-in-capacity of Li 4 SiO 4 in capturing CO 2 during the cyclic reactions, and a higher concentration greatly exacerbates the problem. Moreover, the negative impact of H 2 S is found to have a strong relationship to the reaction temperature. It is proposed that at 325~475 °C, Li 4 SiO 4 and H 2 S react to form bits of Li 2 S and some kinds of sulfates, and at 625~775 °C, a large amount of dense KLiSO 4 is generated covering the surface of the sorbent. In contrast, at a high temperature above 925 °C, sintering of Li 4 SiO 4 plays a critical role, leading to a significant change on its microstructure.
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