AIP Advances
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2022
·Vol. 12
·期 5
·
IF 1.697
Tu Huan,Zhao Guoying,Hou Jingshan,Liu Yufeng,Zhou Yan,Zhang Ganghua,Sun Hong-Tao,Li Ji-Guang,Fang Yongzheng
White light emitting diodes (LEDs) suffer from two most common drawbacks: the deficiency of the red component and the poor thermal stability of silicone. Ce 3+ -doped garnet phosphors with tailor-made luminescence properties can be achieved by variations in {A}, {B}, and {C} cation sites. Herein, a simultaneous ion co-substitution design strategy has been adopted to synthesize a series of (Y, Ca) 3 (Al, Mg) 2 (Al, Si) 3 O 12 garnet phosphors and corresponding phosphor-in-glass (PiG) films. The co-substitution is finely restricted to the assigned sites. The emission peak is shifted from 529 to 565 nm, which is beneficial to obtain low color temperatures and high color rendering using a single phosphor for white LEDs. By employing the as-synthesized phosphor, the corresponding PiG films were fabricated by the low temperature co-sintering technology using the SiO 2 –B 2 O 3 –ZnO–Na 2 O glass system characterized with excellent thermal stability and moisture resistance. The morphological and elemental analyses demonstrated that the as-made phosphor powders were uniformly distributed in the glass host without any interfacial reactions. Finally, modular white LEDs with a high color rendering (Ra = 82.7) is achieved through the as-synthesized PiG film on an InGaN blue chip. This study may open up a facile approach to obtain high quality luminescence based on the mono-luminescence center, avoiding excitation energy wastage and low quantum efficiency aroused by multi-luminescence centers or color compensation phosphors in glass.
研究领域:
材料科学
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光电子学
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固态照明
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无机化学
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应用物理学
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2019
·
IF 4.084
Yinghui Sun,Guojie Zhang,Ying Xu,Riguang Zhang
The catalytic activity of DRM reaction over 1M-1Co-1Ce/AC-N (M = Ca and Mg) catalysts was investigated at 800 °C and under atmospheric pressure. By promoting N-doped activated carbon supported Co-Ce catalysts with alkaline-earth metals to obtain catalysts with better catalytic performance is the main purpose of study. The catalysts were prepared by wet-impregnation method and the influence of impregnation sequence on catalytic performance was also studied. The characterization was conducted using TPR, TPD , XPS, TEM and Raman. The catalyst 1Ca-1Co-1Ce/AC-N promoted with Ca and prepared by co-impregnation exhibited higher catalytic activity than unmodified. This was mainly due to the stronger interaction between metal and support as well as better active metals dispersion. The 1Ca-1Co-1Ce/AC-N catalysts also displayed excellent stability and XPS results indicated that higher Ce 3+ /Ce 4+ and O β /(O α +O β ) ratios were observed on this catalyst. However, the catalyst 1Co-1Ce/1Ca/AC-N prepared with sequential impregnation exhibited poor stability. In addition, the TEM of the spent catalysts revealed that there were a large number of carbons were generated on active metal surface.
研究领域:
催化化学
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能源化学
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材料化学
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环境化学
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化学工程
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SEPARATION AND PURIFICATION TECHNOLOGY
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2020
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IF 5.774
Zheng Zhang,Xiao Du,Qiang Wang,Fengfeng Gao,Tongtong Jin,Xiaogang Hao,Pengfei Ma,Jun Li,Guoqing Guan
A scalable three-dimensional (3D) porous composite electroactive film consisting of λ-MnO 2 , reduced graphene oxide (rGO) and calcium alginate (Ca-alg) was successfully fabricated and employed for the selective extraction of Li + ions with low concentration via an electrochemically switched ion exchange (ESIX) technology. The Li + ion adsorption capacity of the obtained λ-MnO 2 /rGO/Ca-alg composite electroactive film reached as high as 32.7 mg g −1 and more than 90% of its equilibrium adsorption capacity was achieved in 1 h. The λ-MnO 2 /rGO/Ca-alg composite electroactive film displayed evident selectivity towards Li + ions. The separation factors for Li + /Na + and Li + /Mg 2+ reached 1040.57 and 358.96, respectively, while tested in simulated brine. The composite film also showed superior electrochemical stability, and the normalized ion exchange capacity retained at 98.3% of its initial value even after 100 successive cycles. The excellent Li + ion recovery performance of the obtained composite film should be attributed to its low ion transfer resistance owing to the porous network structure and the potential-responsive ion-pumping effect in the ESIX process. In addition, a large-scale of such a composite electroactive film could be effectively fabricated by controlling the spreading area of the mixed solution consisting of λ-MnO 2 , rGO and alginate binder. It is expected that such a scalable 3D porous composite film could be a promising alternative for the recovery of lithium ions from salt lake brine.
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POLYMER DEGRADATION AND STABILITY
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2017
·
IF 3.386
Mei Wang,Xianghai Song,Jianchun Jiang,Jianling Xia,Mei Li
N-(2-amino ethyl) tung maleamic acid (AETMA) and N-(2-amino phenyl) tung maleamic acid (APTMA) were prepared from the ammonolysis of ethidene diamine (ED) and p-phenylenediamine (PPD) respectively with tung-maleic anhydride (TMA). Then LAETMA-Ca, LAPTMA-Ca, LABTMA-Zn and LAPTMA-Zn were separately synthesized through a one-step method and characterized by Fourier transform infrared spectrometry (FTIR), 1 H nuclear magnetic resonance (NMR) and inductively coupled plasma atomic emission spectroscopy (ICP-AES). LAETMA-Ca/LAETMA-Zn and LAPTMA-Ca/LAPTMA-Zn were both used as thermal stabilizers of polyvinyl chloride (PVC) and investigated using Congo red test, thermal aging test, ultraviolet-visible spectrometry, thermogravimetric analysis (TGA), TGA-FTIR, and TGA–mass spectrometry (MS). Their stabilizing efficiencies were compared with other common stabilizers. Dynamic mechanical of the PVC compounds were also studied. The LAPTMA-Ca/LAPTMA-Zn exhibits excellent long-term stability and better plasticization performance for PVC than other stabilizers, and thus can partly replace di(2-ethylhexyl) terephthalate in the processing of PVC. The mechanism underlying the stabilizing action of LAPTMA-Ca/LAPTMA-Zn is suggested.
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CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Jianwei Dao,Zihao Han,Zhihao Jiang,Tiqun Wei,Junlin Xue,Bin Wang,Sicheng Yi,Liang Yang
Narrow-band red phosphors excited by near-ultraviolet light (n-UV) are significant for enhancing the R9 index and can produce high color rendering white LEDs. A range of KSr 1-x-y Ca y PO 4 :xEu 3+ red phosphors were synthesized by high-temperature solid-state reaction method. We investigated the effects of partially substituting Sr 2+ ions with Ca 2+ ions on the phosphors' crystal structure, photoluminescence and thermal stability. Significantly, incorporating Ca 2+ ions enhances the luminescent properties and thermal stability. Under n-UV light excitation, all samples exhibit red emission around 614 nm, corresponding to the 5 D 0 → 7 F 2 transition of Eu 3+ ions. At the doping concentration of Eu 3+ ions (x = 0.08), an optimal KSr 0.52 Ca 0.4 PO 4 :0.08Eu 3+ (y = 0.4) sample was obtained. The excitation wavelength exhibited a slight violet shift from 398 nm to 396 nm. At 150 °C, the luminescence intensity of KSr 0.92 PO 4 :0.08Eu 3+ remains 80.1 % of its value at room temperature, while that of KSr 0.52 Ca 0.4 PO 4 :0.08Eu 3+ reaches 89.7 %. White LED device can be fabricated by combining the as-prepared KSr 0.52 Ca 0.4 PO 4 :0.08Eu 3+ red phosphor with commercial BaMgAl 10 O 17 :Eu 2+ blue and (Ba, Sr) 2 SiO 4 :Eu 2+ green phosphors, along with encapsulation using n-UV LED chip (395–400 nm). The device emits bright white light and exhibits a high color rendering index (Ra = 87.6, R9 = 89.8) and suitable correlated color temperature (CCT = 5523 K) at 300 mA drive current. The results demonstrate that this work provides new application prospects for the fabrication of high color rendering white LEDs using n-UV light.
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CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Xiao Wang,Bingcheng Lin,Jian Wang,Yunfeng Ma,Rong Jin,Guorui Liu,Minghui Zheng
Four inhibitors (CaO, CaS, CH 4 N 2 S, and (NH 4 ) 2 SO 4 ) were employed to inhibit the formation of multiple unintentional persistent organic pollutants (POPs) and environmentally persistent free radicals (EPFRs) using anthracene as a precursor, with CuCl 2 serving as both a transition metal catalyst and chlorine source. The inhibition mechanisms were elucidated in terms of chlorine immobilization, catalyst deactivation, and free radical regulation. The inhibition efficiency of the four inhibitors on polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polychlorinated naphthalenes (PCNs) ranged from 64.7 % to 98.4 %, with the corresponding inhibition rates on toxic equivalency quantity ranging from 86.3 % to 99.7 %. The distribution of homologs shifted towards less chlorinated species, indicating effective suppression of chlorination. Calcium- and nitrogen-containing compounds consumed chlorine sources by forming CaCl 2 , CaClOH, and NH 4 Cl, while sulfur-containing compounds deactivated catalysts by forming CuSO 4 . EPFRs derived from anthracene were identified as carbon-centered anthracene-type and anthraquinone-type radicals. Positive correlations were observed between POPs and EPFRs concentrations, suggesting the pivotal role of organic free radicals as intermediates in POPs formation. Anthraquinones derived from anthracene underwent decomposition, recombination and chlorination, leading to the formation of PCDD/Fs and PCBs. The addition of inhibitors reduced EPFRs concentrations by 74.2–95.1 %. Sulfur- and nitrogen-containing inhibitors generated radicals that attacked POPs precursors and intermediates, forming heteroatomic compounds and inhibiting POPs formation. These findings enhanced the understanding of the source control mechanisms of POPs and provided theoretical and technical support for the synergistic inhibition of POPs and EPFRs in industrial thermal processes.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Xiaolan Chen,Tian Wang,Wanzheng Lu,Tianxiang Cao,Mingzhe Xue,Bing Li,Cunman Zhang
A modified solution method was applied to synthesize cubic garnet solid-state electrolyte Li 7 La 3 Zr 2 O 12 (LLZO) and Li 6.45 Ca 0.05 La 2.95 Ta 0.6 Zr 1.4 O 12 (LCLTZO). The synergetic doping of Ca and Ta is found to induce the formation of cubic LCLZTO with high ionic conductivity of 4.03 × 10 −4 S cm −1 while LLZO without substitution exhibits tetragonal phase with low conductivity. A Li-S cell with sulfur cathode and as-prepared LCLTZO solid electrolyte “separator” was conducted to deliver large initial discharge capacity of 1090 mAh g −1 with high initial Coulombic efficiency up to 92%. Cell with LCLTZO also exhibited better cycling performance at 0.2 C and extremely high Coulombic efficiency (close to 100%) than the cell without solid electrolyte. Better rate performance was also achieved at lower rate (0.2 C, 0.5 C and 1 C) by cell with LCLTZO although it lost advantages at higher rate of 2 C and 5 C due to the limitation of ionic conductivity of LCLTZO. Energy dispersive X-ray spectroscopy (EDS) provided direct evidence that LCLTZO solid electrolyte greatly suppressed the shuttle effect generated by polysulfides . The electrochemical impedance spectroscopy was applied to discuss the difference between cells with and without LCLTZO during the discharge process. Charge transfer reaction referred to soluble polysulfides was found to be slower in cell with LCLTZO than that in cell without solid electrolyte.
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Materials Today
·
2025
·
IF 22
Haiping Luo,Shenglan Zhou,Wenjie Deng,Jiahao Liu,Jiaqing Peng,Bo Li,Zhihua Xiong,Wei Wang,Xinyu Ye
Fe 3+ is a promising near-infrared (NIR) activator ion due to its tunable emission and non-toxicity, which has attracted growing interest. However, developing high-performance broadband NIR-emitting phosphors based on Fe 3+ remains a significant challenge. In this work, we present Fe 3+ -activated A 2 LuSbO 6 (A = Ba/Sr/Ca) double perovskite phosphors, which exhibit unusually long-wavelength NIR emission (>850 nm). By adopting a cation substitution strategy at the A-site, we designed the gradual replacement of large-radius ions with small-radius ions, achieving controllable tuning of emission from 847 nm to 937 nm. This substitution process simultaneously reduces structural symmetry and induces octahedral distortion, which breaks the spin-forbidden transition of Fe 3+ and enhances luminescence performance. However, the continuous emission redshift leads to a large Stokes shift, which suppresses Fe 3+ luminescence. The combined effect of these two factors results in optimal luminescence efficiency in Sr 2 LuSbO 6 :1.0 %Fe 3+ (SLSO) sample, with internal/external quantum efficiencies (IQE/EQE) of 94.8 %/54.5 %. To further enhance luminescence performance, we introduced the rare-earth Yb 3+ , establishing an efficient Fe 3+ →Yb 3+ energy transfer (ET) channel that reduces non-radiative transition losses. Compared with the Yb 3+ -free sample, the SLSO:1.0 %Fe 3+ , 3.0 %Yb 3+ sample exhibits a broadened FWHM from 115 nm to 180 nm, enhanced IQE and EQE of 98.1 % and 56.4 %, respectively, and 13 % improved thermal stability. Finally, a pc-LED device based on the SLSO:1.0 %Fe 3+ , 3.0 %Yb 3+ phosphor demonstrates potential for applications in NIR spectroscopy analysis, night vision, biomedical imaging, and other fields. This work lays a foundation for further research on strategies to regulation the optical properties of Fe 3+ -activated NIR phosphors.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2025
·Vol. 36
·期 18
·1-16
·
IF 2.8
Yang Zaizhi,Shen Yalong,Zhu Yuan,Jiang Xiaoming,Liu Rui,Yang Zhen,Wang Shouliang,Xu Dong
Flash sintering has revolutionized the field of advanced ceramic preparation with the low heating temperature and extremely short sintering time. The difference of doped ions radius can influence the defect structure and resistivity of the sample through lattice distortion, subsequently altering the parameters and dielectric properties of flash sintering samples. By flash sintering technology, co-doped TiO 2 ceramics with the acceptor ions (Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ ) and donor ions (Nb 5+ ) were successfully prepared at 1100 °C for 24 min. According to the blackbody radiation model, Mg 2+ and Nb 5+ co-doped TiO 2 ceramics exhibit the highest surface temperature at the moment of flash sintering, approximately 1852 °C. Additionally, the co-doped TiO 2 ceramics with Ba 2+ and Nb 5+ ions exhibit the strongest polarization effect, with a dielectric constant above 10 5 . The acceptor ions with larger ions increase oxygen vacancies by enhancing the stability of defect complexes. The excellent giant dielectric properties are attributed to the combined action of the electron-pinned defect dipole effect and the internal barrier layer capacitor effect.
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高影响因子
Frontiers in Bioengineering and Biotechnology
·
2022
·
IF 6.064
Xinming Feng,Yujin Cao,Wei Liu,Mo Xian
Fluoride plays an important role in the fields of materials and medicine. Compared with chemical synthesis, fluorinases are natural catalysts with more application potential, which provide a green and effective way to obtain organofluorine. However, the application of fluorinases is limited by certain factors, such as the limited number of enzymes and their low activity. In this work, two new fluorinases from Amycolatopsis sp. CA-128772 and Methanosaeta sp. PtaU1.Bin055 were identified by gene mining and named Fam and Fme, respectively. The activities of these two enzymes were reported for the first time, and Fme showed good thermal stability, which was different from the reported fluorinases. In addition, the activity toward natural substrate of Fam was improved by site-directed mutagenesis, the catalytic efficiency ( k cat /K m ) of the best mutant containing two amino acid substitutions (T72A and S164G) toward the substrate S-adenosyl-L-methionine was improved by 2.2-fold compared to the wild-type. Structural modeling analysis revealed that the main reason for the increased enzyme activity might be the formation of a new substrate channel. Experimental evidence suggests that the substrate channel may indeed play a key role in regulating the function of the fluorinases.
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PubMed
高影响因子
Gels
·
2022
·Vol. 8
·期 6
·331
·
IF 4.432
Jiayan Shen,Shutong Du,Ziyao Xu,Tiansheng Gan,Stephan Handschuh-Wang,Xueli Zhang
Artificial shape-morphing hydrogels are emerging toward various applications, spanning from electronic skins to healthcare. However, the low freezing and drying tolerance of hydrogels hinder their practical applications in challenging environments, such as subzero temperatures and arid conditions. Herein, we report on a shape-morphing system of tough organohydrogels enabled by the spatially encoded rigid structures and its applications in conformal packaging of “island–bridge” stretchable electronics. To validate this method, programmable shape morphing of Fe (III) ion-stiffened Ca-alginate/polyacrylamide (PAAm) tough organohydrogels down to −50 °C, with long-term preservation of their 3D shapes at arid or even vacuum conditions, was successfully demonstrated, respectively. To further illustrate the potency of this approach, the as-made organohydrogels were employed as a material for the conformal packaging of non-stretchable rigid electronic components and highly stretchable liquid metal (galinstan) conductors, forming a so-called “island–bridge” stretchable circuit. The conformal packaging well addresses the mechanical mismatch between components with different elastic moduli. As such, the as-made stretchable shape-morphing device exhibits a remarkably high mechanical durability that can withstand strains as high as 1000% and possesses long-term stability required for applications under challenging conditions.Keywords:organohydrogels;anti-freezing;shape-morphing;tough hydrogels;flexible electronics
研究领域:
材料科学
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柔性电子
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生物医学工程
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聚合物科学
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DOI
PubMed
高影响因子
Russian Journal of Physical Chemistry A
·
2022
·Vol. 96
·期 8
·1761-1767
·
IF 0.791
Chen Yu,Liu Miao
Abstract A modified polyacrylamide gel route with urea used as fuel was used to synthesize the MFe 2 O 4 (M = Mg, Ca, Ba) iron oxides with high adsorption capacity for removal of Cd(II) from water treatment. The phase structure, functional group, porous structure and adsorption performance of MFe 2 O 4 (M = Mg, Ca, Ba) iron oxides were characterized by X-ray-diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), N 2 adsorption–desorption isotherm and 721 spectrophotometer. The result indicates that the phase forming temperature of MFe 2 O 4 , the content of carbonate ion in MFe 2 O 4 increases with the increasing of the radius of M-site metal ion. The E g value, BET surface area and adsorption capacity for removal of Cd(II) from water treatment decreases with the increasing of the radius of M-site metal ion. The experimental isotherm of MFe 2 O 4 (M = Mg, Ca, Ba) iron oxides were described by the Langmuir model. MgFe 2 O 4 iron oxide exhibits a best adsorption performance for removal of Cd(II) from water treatment by the adsorption process, with a maximum adsorption capacity of ca. 221.36 mg/g than that of other iron oxides. The present synthetic route could be possibly extended to synthesize other porous metal oxide materials with special porous structures for various applications.
研究领域:
环境科学
·
材料科学
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