JOURNAL OF RARE EARTHS
·
2022
·
IF 4.632
Pan Liang,Lianqing Li,Tong Shen,Wenli Lian,Zhihong Liu
In this work, through a facile method of low-temperature (only 350 °C) self-reduction, 1D nano-sized M 2 B 5 O 9 Cl:Eu 2+ (M = Sr, Ca) blue phosphors with highly efficient performance can be obtained. The crystal structure, morphology and photoluminescence (PL) properties including thermal stability of M 2 B 5 O 9 Cl:Eu 2+ (M = Sr, Ca) phosphors were investigated. The M 2 B 5 O 9 Cl:Eu 2+ (M = Sr, Ca) phosphors show broad band excitation spectra and narrow band emission spectra . The photoluminescence quantum yields (PLQY) of M 2 B 5 O 9 Cl:Eu 2+ (M = Sr, Ca) are as high as 98% and 87.2%, respectively. Furthermore, the color purities of M 2 B 5 O 9 Cl:Eu 2+ (M = Sr, Ca) can reach 99.1% and 93.2%, respectively. When heated up to 150 °C, the emission intensities of M 2 B 5 O 9 Cl:Eu 2+ (M = Sr, Ca) phosphors can still keep 72.7% and 80.0%, respectively. Finally, the above-mentioned phosphors exhibit outstanding performance when manufacturing WLEDs.
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高影响因子
APPLIED CATALYSIS A-GENERAL
·
2023
·
IF 5.5
Cheng Cang Li,Da Jian Li,Shu Tian Yin,Ze Zhen Wang,Chen Lan Liu,Chun Hui Zhou
Glycerol can be converted to allyl alcohol via deoxydehydration using molybdenum-vanadium, rhenium and iron based catalysts. However, the dehydration causes severe coking at strong acid sites on the surface of catalyst. Molybdenum-vanadium oxide supported on calcium oxide-intercalated montmorillonite (MoV-CaMMT) was prepared by oxalate anion intercalation followed by impregnation. MoV-CaMMT displayed the best catalytic performance of 86.5% glycerol conversion and good stability in 5 h. Correlating the results of XRD, XPS and TG analysis, it can be demonstrated that the addition of CaO in the catalyst preparation is conducive to the crystallization and dispersion of vanadium oxides, and reduces the acid strength, while the presence of a few vanadium dioxide and the stable conversion of V 4+ and V 5+ are the reasons for enhancing coking-resistance of MoV-CaMMT. Additionally, NH 3 -TPD analysis proved the coexistence of weak and strong acid sites in MoVO x , which are conducive to the formation of acetol.
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高影响因子
FUEL
·
2023
·
IF 7.4
Xiaoshan Dong,Jian Wang,Fawei Lin,Jian Li,Tianxiao Yu,Beibei Yan,Guanyi Chen
Photothermal steam reforming (PTR) has emerged as an attractive approach for catalytic tar removal, due to the excitation of the photothermal synergistic effect. However, the role of oxygen species in PTR is still unclear. In this paper, the effect of alkaline earth metals (Ca and Sr) A-site-substitution on perovskite LaNi 0.6 Mn 0.5 O 3 was investigated to reveal the role of oxygen species in PTR. The substitution of alkaline earth metals into perovskite lattice affected the dispersion of nickel and significantly adjusted the active oxygen species content on the catalyst surface. Oxygen species are crucial to the carbon deposition behavior of catalysts in PTR. La 0.7 Ca 0.3 Ni 0.6 Mn 0.5 O 3 was rich in reactive oxygen species, which effectively inhibited the deposition and graphitization of coke, resulting in its good coke resistance and catalytic stability in PTR. Ultraviolet–visible light (UV–vis) supported the formation of oxygen vacancies and the dissociation of H 2 O to hydroxyl radicals through the photochemical reaction, which ultimately increased the surface adsorbed oxygen contents. Meanwhile, UV–vis promoted the migration and reaction of lattice oxygen. The photoactivation of oxygen species by UV–vis effectively enriched active oxygen species and improved the coke resistance, which resulted in enhanced catalytic stability of PTR at low-temperature.
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高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Tianxing Gong,Tingyu Li,Lisha Meng,Yadong Chen,Tao Wu,Jingqiu Zhou,Guoxiu Lu,Zhiguo Wang
Native bone is piezoelectric in nature and generates abundant surface charges under mechanical compression, which regulate osteoblast proliferation, differentiation, adhesion, and so on. Poly (vinylidene fluoride) (PVDF) is becoming one of the most popular piezoelectric polymers because of its easy processability and good biocompatibility. Unfortunately, because only the β and γ crystal phases of PVDF have piezoelectricity, post-treatments, for example, polarizing at high temperature, are required to enhance the piezoelectricity of PVDF scaffolds after fabrication. In this study, we reported a phase-separation-hydration method to fabricate a calcium phosphate silicate (CPS)-doped PVDF scaffold. Our method fabricated a better piezoelectric scaffold than native bone without further processing (∼ 3 pC/N vs. 0.7 pC/N). In addition, the scaffold was mechanically compatible (∼ 7 MPa) with the cancellous bone with sufficient porosity (∼ 45%) to facilitate osteoblast infiltration and bone ingrowth. The in vitro biocompatibility analyses proved that the prepared CPS-PVDF scaffold was biocompatible with osteoblast cells and encouraged osteoblast redifferentiation. In conclusion, our results suggest that this CPS-PVDF scaffold is a promising candidate for bone tissue engineering applications.
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高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Handan Liu,Yanyan Liu,Dan Xu,Long Chen,Wen Guo,Tiantian Gu,Feng Yu,Gang Wang
Ti 3 C 2 T x , a member of the MXene, has attracted extensive interest because of its high conductivity, unique two-dimensional (2D) structure and intrinsic pseudocapacitance for supercapacitors. Flexible and freestanding Ti 3 C 2 T x films are promising electrodes for functioned supercapacitors used in wearable and portable electronic devices. However, the severe self-restacking of 2D Ti 3 C 2 T x nanosheets restraints their practical application. Herein, freestanding and flexible three-dimensional (3D) cross-linked Ti 3 C 2 T x -Ca-SA (sodium alginate) films with expanded Ti 3 C 2 T x interlayer spacing are reported. The expanded interlayer spacing allows more electrolyte ions to quickly intercalate providing more intercalation pseudocapacitance, while the 3D cross-linked microstructure ensures a continuous conductive network facilitating charges transport. Attributing to the unique structure, the Ti 3 C 2 T x -Ca-SA film delivers an outstanding areal capacitance (633 mF cm −2 at 5 mV s −1 ). Meanwhile, the assembled all-solid-state pseudocapacitor shows good flexibility and capacity stability under various bending conditions. The device exhibits a high energy density up to 12.6 µWh cm −2 at the power density of 375 µW cm −2 and excellent cycling stability, which are much better than prior reported state-of-the-art supercapacitors. This research exploits a simple method to optimize the structure of MXene as state-of-the-art electrodes for high-performance flexible energy-storage devices.
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PubMed
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2021
·Vol. 28
·期 23
·30312-30322
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IF 4.223
Wang Yingya,Zhang Hanbing,Yaseen Muhammad,Tong Zhangfa,Chen Ninghua,Shi Huazhen
In order to endow alkaline Ca-bentonite (ACB) with magnetic separation ability, simultaneously obtain better magnetic stability and stronger removal capacity of heavy metal cations; magnetic alkaline Ca-bentonite/carboxymethylcellulose-chitosan film (MACB/C-C) was prepared by organic modification of magnetic alkaline Ca-bentonite (MACB) using non-toxic carboxymethylcellulose and chitosan. Textural characterization results revealed that magnetic Fe 3 O 4 nanoparticles were successfully immobilized on ACB and modified with C-C. The functionalized layer of C-C concurrently enhanced the stability of Fe 3 O 4 and removal performances of heavy metal cations. Adsorption results indicated that MACB/C-C exhibited thorough separation from aqueous solution and greater uptake ability for Pb(II) and Cd(II) (483 mg·g −1 and 123 mg·g −1 ) than the nascent MACB (335 mg·g −1 and 76 mg·g −1 ), respectively, at pH 5 and 25 °C temperature. The adsorption of Pb(II) and Cd(II) on MACB/C-C mainly occurred via surface precipitation and complexation when pH > 2. MACB/C-C could be efficiently recycled with marginal decrease in adsorption capacity. The current approach credited to the convenient operation, simplified synthesis, and high efficiency of MACB/C-C could be deemed as a promising alternative for the removal of heavy metal cations from wastewater.
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PubMed
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2021
·
IF 5.302
Bing Liu,Ke Sha,Meng Fei Zhou,Kai Xin Song,Yu Hui Huang,Cheng Chao Hu
Two novel low- ε r gallates MGa 2 O 4 (M = Ca, Sr) have been synthesized via a standard solid-state reaction method. According to the X-ray diffraction results, CaGa 2 O 4 crystallizes in space group Pna2 1 with an orthorhombic symmetry, while SrGa 2 O 4 belongs to the monoclinic P2 1 / c system. Both ceramics show ever-improving microstructures with the increasing sintering temperature . The optimal microwave dielectric properties ( ε r = 9.2, Qf = 66,000 GHz, τ f =–85 ppm/°C for SrGa 2 O 4 and ε r = 10.6, Qf = 15,400 GHz, τ f =–58 ppm/°C for CaGa 2 O 4 ) are obtained when sintered at 1275 °C. A patch antenna is fabricated using SrGa 2 O 4 ceramics as the substrate, which realizes a return loss of –19.94 dB and total efficiency of –1.38 dB (72.8 % in power ratio) at 4.84 GHz. The exceptional performances indicate that SrGa 2 O 4 ceramics are promising candidates for antenna applications at the Sub-6 GHz band.
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高影响因子
ENERGY CONVERSION AND MANAGEMENT
·
2020
·
IF 8.208
Rui Han,Jihui Gao,Siyu Wei,Fei Sun,Qingling Liu,Yukun Qin
Thermochemical energy storage based on the Calcium-Looping process characterized high energy density, low cost, and scalability, which is an advantageous candidate for the heat storage systems of Concentrated Solar Power plants. The main disadvantage of Calcium-Looping technology is the rapid decrease in the reactivity of CaO during cycling due to sintering. Many methods have been developed to synthesize high-cycling-behavior CaO-based materials. However, the state-of-the-art synthesized CaO-based materials remain far from the requirements due to the lack of consideration from an application perspective, which not only demands high-cycling-behavior but also needs to consider volumetric energy density. In this work, dense CaO/Al 2 O 3 composites were fabricated using the space-confined chemical vapor deposition method and considering both stability and volumetric energy density. Among different Ca-precursors, calcium formate does not expand during calcination, thus possesses a relatively dense structure, and taken together with the deposition of Al 2 O 3 on the surface of CaO grains obtained composites possessing high density and excellent stability. The optimized composite with 10 mol.% Al achieves a high volumetric energy density of 2.07 GJ/m 3 after 20 cycles, which is 1.58, 4.31, and 6.68 times of the capacity of limestone-derived CaO, sol–gel based CaO/Al 2 O 3 composites, and wet-mixing based CaO/Al 2 O 3 composites, respectively. This study presents a design principle for CaO-based heat storage materials, which are becoming denser and more stable.
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高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2020
·Vol. 31
·期 11
·8464-8471
·
IF 2.22
Si Shufang,Deng Hongmei,Wang Tiantian,Yang Pingxiong,Chu Junhao
Perovskite compounds Bi 0.7 A 0.3 FeO 3−δ (BAFO) (A = Ca, Sr, Pb, and Ba) with improved optical and magnetic properties have been synthesized by solid-state method. The effect of bivalent ions substitution on the phase transition, microstructure, optical, and magnetic properties are investigated in detail. X-ray diffraction and Raman scattering spectra analyses indicate the phase transition from rhombohedral to cubic in doped samples and the coexistence of the two phases in BBFO, inducing strong lattice distortions. A blue shift observed in d–d transitions energies can reveal the decreased internal chemical pressure, thus leading to the slight increase in bandgaps of BSFO, BPFO, and BBFO. While, narrowed bandgap of 1.96 eV can be found in BCFO for the increased tailing of the conduction band edge into the gap. Besides, room-temperature ferromagnetism has been observed in Sr-, Pb-, and Ba-doped samples which can be resulted from the suppression of spiral structure of BFO. These results lay a solid foundation on further exploring the potential abilities of BFO ceramics as multiferroic photovoltaic materials.
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Catalysis Science & Technology
·
2020
·Vol. 10
·期 17
·5829-5839
·
IF 5.721
Hanlin Chen,Gaoling Wei,Xiaoliang Liang,Peng Liu,Yunfei Xi,Jianxi Zhu
Thermal catalytic oxidation is regarded as an effective technique to eliminate volatile organic compounds (VOCs), whereby perovskite-type oxides have been reported as low-cost and highly efficient transition metal catalysts. In this study, we employ two facile modification methods, i.e., Ca substitution and citric acid etching, to further improve the catalytic activity of LaCoO3 perovskite for toluene oxidation. The Ca-substituted LaCoO3 (La0.9Ca0.1CoO3) and citric acid-etched LaCoO3 (LaCoO3–CA) show T90 values at 220 and 215 °C, respectively, which are substantially lower than that of pristine LaCoO3 (305 °C). When LaCoO3 is modified by both Ca substitution and citric acid etching, i.e., La0.9Ca0.1CoO3–CA, the T90 further decreases to 202 °C, even lower than that of the commercial catalyst 0.5 wt% Pt/Al2O3 (208 °C). In terms of specific reaction rate at 200 °C, the activity of the above catalysts is also enhanced as follows: LaCoO3 (0.14 μmol s−1 m−2) < La0.9Ca0.1CoO3 (0.31 μmol s−1 m−2) < LaCoO3–CA (0.47 μmol s−1 m−2) < La0.9Ca0.1CoO3–CA (0.63 μmol s−1 m−2). The effects of Ca substitution and citric acid etching are discussed in light of the crystal structure, morphology, and lattice defects. On the one hand, Ca substitution and citric acid etching increase the specific surface area and pore volume, which facilitate the contact between toluene and active sites. On the other hand, these methods produce more oxygen vacancies, enhance the reducibility, and facilitate the adsorption of oxygen. The above merits result in the increase in the specific reaction rate. The modified catalysts show a better water resistance than pristine LaCoO3. As verified in the H2O-TPD characterization, this phenomenon is ascribed to the generation of surface hydroxyl groups, which are beneficial for toluene oxidation at high humidity.
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高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2019
·
IF 4.561
Hengxin Fang,Zhixu Tang,Xinjuan Liu,Yongli Huang,Chang Q. Sun
It has been a long pursuit to discriminate the ionic roles of mono- and di-valent salt solutions in modulating the hydrogen bonding network and solution properties. We attended this issue by examining the effect of concentrated YX 2 (Y Mg, Ca, Sr; X Cl, Br) solvation on O:H O bonds transition from the mode of ordinary water to hydration in terms of the number fraction f YX2 ( C ) and the segmental O:H O bond phonon stiffness shift Δω(C) with C being the solute concentration. The invariant df Y ( C ) / dC at C ≤ <0.05 suggests that the small Y 2+ forms a constantly-sized hydration droplet with weak responding to interference of other ions because its hydrating H 2 O dipoles screen mostly its electric field. However, the number inadequacy of the highly-ordered hydrating H 2 O dipoles partially screens the large X − . The X − ↔ X − electrostatic repulsion weakens its electric field. The concentration-trend consistency of the f YX2 ( C ), the solution conductivity σ YX2 ( C ), and surface stress (contact angle) θ YX2 ( C ) for YX 2 solutions clarifies their common origin of ionic polarization. However, the Jones–Dale notion disobedience of the viscosity η YX2 ( C ) suggests the dominance of the inter-ion repulsion.
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高影响因子
THERMOCHIMICA ACTA
·
2017
·
IF 2.236
Mei Wang,Xianghai Song,Jianchun Jiang,Jianling Xia,Shouhai Li,Mei Li
Hydroxyl and nitrogen rich groups-containing tung-oil-based Ca/Zn (Ca-HTMA-1, Zn-HTMA-1, Ca-HTMA-2 and Zn-HTMA-2) and polyol thermal stabilizers (HTMA-1 and HTMA-2) were successfully synthesized from tung-maleic anhydride (TMA). The thermal stability tests show that CaSt 2 /Zn-HTMA-2/HTMA-2 displays the best thermal stability for poly(vinyl chloride) (PVC). The superior performance is attributed to the synergistic effect of CaSt 2 , Zn-HTMA-2 and HTMA-2, which is originated from the simultaneous introduction of hydroxyl and nitrogen rich groups into the Zn-HTMA-2 and HTMA-2 structures. The nitrogen rich groups can absorb the hydrogen chloride released during the PVC degradation process, which helps to inhibit the “autocatalytic effect” and lead to better long term thermal stability. Besides, hydroxyl groups can form stable chelates with ZnCl 2 to avoid “zinc-burning” during the later PVC degradation. Besides the better stabilization performance, CaSt 2 /Zn-HTMA-2/HTMA-2 also displays comparable plasticization performance for PVC compared with other stabilizers. A possible stabilizing mechanism of PVC/CaSt 2 /Zn-HTMA-2/HTMA-2 system was presented.
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高影响因子
危险品化学品经营许可证（带存储）