JOURNAL OF INCLUSION PHENOMENA AND MACROCYCLIC CHEMISTRY
·
2017
·Vol. 90
·期 1
·149-155
·
IF 1.095
Dong Peng,Li Zeyu,Ji Dong,Wang Xiaorui,Yun Hongfei,Du Zhisong,Bian Jie,Li Guixian
Modified Y type catalyst (M-Y) shows great potential for the preparation of toluene attribute to catalyst topology and synergistic effect of Lewis acid and Brönsted acid in the alkylation reaction. However, it still remains a big challenge to build a reaction mechanism. Thereby, based on the study of HZSM-5, H-beta and M-Y catalysts structure and physical properties, a plausible reaction mechanism was proposed. The samples were characterized by X-ray diffraction, N 2 adsorption/desorption, Fourier transform infrared absorption spectra and Pyridine adsorption infrared. The activity of catalysts was tested in benzene alkylation with methanol and was found to be in the following increasing order: Na-Y (no effect) < H-Y << HZSM-5 < H-beta < M-Y.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2022
·
IF 5.876
Bo Meng,Shenyong Ren,Xinyue Zhang,Kang Chen,Wenkai Wei,Qiaoxia Guo,Baojian Shen
Brønsted acid of zeolite Y plays an important role in catalytic cracking reaction. However the proportion of strong Brønsted acid in conventional zeolite Y is small which limits the efficiency of transformation. This work described a way to achieve the goal of significant increasing the density of strong Brønsted acid via introducing Zr 4+ into the framework of zeolite Y. The density of strong Brønsted acidity increased from 0.085 (HY) to 0.208 mmol/g ([Zr,Al]-HY). Systematic characterization results showed that the introduction of Zr 4+ could produce more Si(1Al) but less Si(3Al) and Si(2Al) species in zeolite which was responsible for the high density of Brønsted acid. And abundant mesopores were also formed during the Zr 4+ implanting. For the catalytic cracking results of n-octane, the conversion on [Zr,Al]-HY was 1.67 times of that on conventional HY. The apparent activation energy of cracking n-octane on [Zr,Al]-HY was reduced to 73.3%, which indicated that the increase of strong Brønsted acid had significant effect on catalytic cracking. On the other hand, a large number of mesoporous structures of [Zr,Al]-HY provided a good foundation for the catalytic cracking of steric hindered 1.3.5-triisopropylbenzene (1,3,5-TIPB).
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2015
·Vol. 3
·期 33
·17217-17223
·
IF 7.443
Liang Huang,Xiang Gao,Qiang Dong,Zhimi Hu,Xu Xiao,Tianqi Li,Yongliang Cheng,Bin Yao,Jun Wan,Dong Ding,Zheng Ling,Jieshan Qiu,Jun Zhou
Pseudocapacitors, which store charge through fast reversible redox reactions occuring at the surface of the electrode, could offer higher specific capacitance than electrochemical double-layer capacitors (EDLCs). However, the prime pseudocapacitive phase, transition metal oxides usually have poor electronic conductivity, limiting their practical application. Here, we fabricated highly conductive HxMoO3−y nanobelts as electrode materials for pseudocapacitors. This electrode has demonstrated great electrochemical activity in various aqueous cation solutions with the highest volumetric capacitance of over 350 F cm−3. Significantly, this electrode has high specific capacitance as well as excellent cycling stability in sea water. Moreover, this hybrid composite also exhibits remarkable ion electrosorptive capacity (4 mg g−1) as a desalination electrode.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2021
·Vol. 11
·期 5
·2866-2871
·
IF 3.361
Hui Cheng,Yanfeng Yin,Jianbo Tang,Donghua Fan,Jan J. Huang,Shengye Jin
All-inorganic perovskite materials have emerged as highly promising materials for solar cells and photoelectronic applications. However, the poor stability of perovskites in ambient conditions significantly hampers their practical applications. In this work, we report a three-step synthesis of size tunable CsPbX3 (X = Br, Cl, or I) quantum dots (QDs) embedded in zeolite-Y (CsPbX3-Y), which involves efficient chemical transformation of non-luminescent Cs4PbX6 to highly luminescent CsPbX3 by stripping CsX through an interfacial reaction with water. We show that the size and the emission of CsPbX3 in CsPbX3-Y can be tuned by the amount of water added as well as the halide composition. More importantly, the as-prepared CsPbX3-Y show significantly enhanced stability against moisture upon protection by zeolite-Y. This work not only reports a new pathway for the preparation of highly luminescent CsPbX3 but also provided new insights into the chemical transformation behavior and stabilization mechanism of these emerging perovskites.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2021
·
IF 4.311
Yingjie Fei,Chunying Zhu,Taotao Fu,Xiqun Gao,Youguang Ma
The breakup flow patterns, the neck dynamics and the tip dynamics of bubbles stabilized by adsorptive nanoparticles in microfluidic Y-junction were investigated. Three flow patterns were observed in the Y-junction: non-breakup, breakup with partial obstruction, and breakup with permanent obstruction. Compared with bubbles stabilized only by surfactants (conventional bubbles), bubbles stabilized by nanoparticles (hardening bubbles) are more difficult to breakup. The breakup process with partial obstruction could be divided into three stages: squeezing, transition and pinch-off. Nanoparticles have little effect on the squeezing stage, but could greatly prolong the transition stage while accelerate the pinch-off stage. The difference between hardening and conventional bubbles is weakened, even disappears as the dispersion flow rate increases. Besides, the “rigid” surface of hardening bubbles could cause the decrease of the curvature of daughter bubble tips and the tunnels between the daughter bubbles and the channel wall in comparison with conventional bubbles.
研究领域:
流体力学
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纳米技术
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界面化学
✓ 已验证
DOI
高影响因子
Materials
·
2023
·Vol. 16
·期 10
·3671
·
IF 3.4
Xiangqian Kong,Zhihua Qiu,Lina Wu,Yunfei Lei,Lisheng Chi
Rare earth luminescent materials demonstrate significant advantages in lighting and energy saving, and detection etc. In this paper, a series of Ca2Ga2(Ge1-xSix)O7:y%Eu2+phosphors were synthesized by high-temperature solid-state reaction and characterized by X-ray diffraction and luminescence spectroscopy methods. The powder X-ray diffraction patterns reveal that all the phosphors are isostructural with a space group ofP4¯21m. The excitation spectra of Ca2Ga2(Ge1-xSix)O7:1%Eu2+phosphors exhibit significant overlapping of the host and the Eu2+absorption bands, which facilitates Eu2+absorbing the energy to increase its luminescence efficiency when excited by visible photons. The emission spectra show that the Eu2+doped phosphors have a broad emission band with a peak centered at 510 nm arising from the 4f65d1→4f7transition. Variable temperature fluorescence reveals that the phosphor has a strong luminescence at low temperature but has a severe thermal quenching effect when temperature rises. The optimal Ca2Ga2(Ge0.5Si0.5)O7:1.0%Eu2+phosphor shows promise for application in the field of fingerprint identification based on the experimental results.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Nano Materials
·
2020
·
IF 0
Cederick Cyril Amoo,Mingquan Li,Aqsa Noreen,Yajie Fu,Elton Maturura,Ce Du,Ruiqin Yang,Xinhua Gao,Chuang Xing,Noritatsu Tsubaki
Keen interest is taken in zeolite-encapsulated metal nanoparticles (NPs) owing to their excellent performance and ultrastability in heterogeneous catalysis. Herein, we propose a simple and efficient method to contain Fe NPs within zeolite Y microcrystals. First, a low-pressure technique was developed to successfully synthesize the zeolite Y microcrystals. The technique was then invoked, using Fe NPs fixed in nanosized C spheres as a precursor, to prepare zeolite Y-embedded Fe composite catalysts. The C spheres served as a template that restricted Fe NP growth within zeolite Y. Above all, the successful confinement of small Fe NPs within the microcrystals of zeolite Y enhanced the catalyst activity with 36.2% selectivity for light olefins (C2–C4=) at a CO conversion of 91.2% during evaluation in Fischer–Tropsch synthesis. The techniques presented in this work open up a new avenue worth exploiting for the synthesis of nano/microcrystalline materials and highly active metal–zeolite composites in heterogeneous catalysis.
研究领域:
材料科学
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催化化学
✓ 已验证
DOI
RSC Advances
·
2018
·Vol. 8
·期 44
·25057-25064
·
IF 2.936
Wei Wan,Jia-Yi Sun,Shi Ye,Qin-yuan Zhang
Graphitic carbon nitride (g-C3N4) has aroused broad interest in the field of photocatalysis and luminescence as a kind of metal-free semiconductor with a suitable band gap of ∼2.7 eV. The properties largely depend on the polymerization degree of g-C3N4. This research exploits the nanocages of zeolite-Y to confine the polymerization of the melamine monomer to form g-C3N4. The composites are achieved via a facile two-step method, i.e., melamine–Na+ ion exchange reaction in the cage of the zeolite and subsequent calcination. BET measurement and transmission electron microscopy (TEM) confirm that the g-C3N4 is encapsulated in zeolite-Y, and the polymerization degree can be controlled by the melamine contents exchanged with Na+ in the cages of zeolite-Y. Photoluminescence and vibration spectroscopy also show the features of g-C3N4 with different polymerization degrees in the zeolite-Y composites. This research gives a perspective of fabricating subnanoscale g-C3N4 in porous zeolite, which may find potential applications in photocatalysis and optoelectronics.
研究领域:
材料科学
·
光学
·
催化化学
✓ 已验证
DOI
PubMed
高影响因子
RSC Advances
·
2015
·Vol. 6
·期 1
·778-785
·
IF 3.84
Huajun Li,Yining Wu,Xiaoda Wang,Chunying Zhu,Taotao Fu,Youguang Ma
This paper is mainly focused on the investigation of the magnetofluidic control of the breakup of ferrofluid droplets in a symmetric Y-junction. The asymmetric breakup of the ferrofluid droplet or non-breakup with filtering the mother droplet into a desired branch to separate it from the satellite droplet was implemented by an external magnetic field. The breakup processes of ferrofluid droplets with and without the magnetic field were studied systematically. The influences of both the flow rate ratio between the continuous phase and dispersed phase and the magnetic flux density on the sizes of daughter droplets were determined. It was found that the attractive magnetic force shifted the mass center of mother droplet in the upstream main channel, which accordingly facilitated the asymmetric breakup of the droplet at the downstream Y-junction. A power function correlation for precisely predicting the sizes of daughter droplets was proposed by introducing the magnetic Bond number (Bom). Moreover, we also found that the controllable magnetic force could promote the pattern transition between the breakup and non-breakup of ferrofluid droplets.
研究领域:
微流体力学
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材料科学
·
流体力学
✓ 已验证
产品关联
DOI
高影响因子
Nature Communications
·
2024
·Vol. 15
·期 1
·1-18
·
IF 14.7
Zhang Yan,Shen Jiayi,Xie Famin,Liu Zhiwei,Yin Fangfang,Cheng Mingxiu,Wang Liang,Cai Meiting,Herzog Herbert,Wu Ping,Zhang Zhi,Zhan Cheng,Liu Tiemin
Resistance to stress is a key determinant for mammalian functioning. While many studies have revealed neural circuits and substrates responsible for initiating and mediating stress responses, little is known about how the brain resists to stress and prevents overreactions. Here, we identified a previously uncharacterized neuropeptide Y (NPY) neuronal population in the dorsal raphe nucleus and ventrolateral periaqueductal gray region (DRN/vlPAG) with anxiolytic effects in male mice. NPY DRN/vlPAG neurons are rapidly activated by various stressful stimuli. Inhibiting these neurons exacerbated hypophagic and anxiety responses during stress, while activation significantly ameliorates acute stress-induced hypophagia and anxiety levels and transmits positive valence. Furthermore, NPY DRN/vlPAG neurons exert differential but synergic anxiolytic effects via inhibitory projections to the paraventricular thalamic nucleus (PVT) and the lateral hypothalamic area (LH). Together, our findings reveal a feedforward inhibition neural mechanism underlying stress resistance and suggest NPY DRN/vlPAG neurons as a potential therapeutic target for stress-related disorders.
研究领域:
神经科学
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应激生物学
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行为神经科学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Materials Research and Technology-JMR&T
·
2024
·
IF 6.2
Bo Ma,Zhiqin Wen,Jiedong Qin,Taoyi Lu,Li Tang,Zhenyu Wu,Yuhong Zhao
In this paper, in order to improve the mechanical properties of high-entropy fluorite oxides (HEFOs), five equimolar multicomponent oxides were synthesized by solid-phase reaction method by using element Y replacing one of the five cations in (Ce 0.2 Zr 0.2 La 0.2 Sm 0.2 Nd 0.2 )O 2- δ . The substitution of La, Sm or Nd in (Ce 0.2 Zr 0.2 La 0.2 Sm 0.2 Nd 0.2 )O 2- δ with Y element are able to form single-phase HEFOs at 1600 °C, while Ce 4+ and Zr 4+ replaced by Y 3+ contains a large number of secondary phase. The former three components are almost dense and smooth, and all the elements are uniformly distributed with no obvious segregation and agglomeration. The Ce 3+ concentration of Y-substituted Sm HEFOs is calculated to be 13.7%, yielding a nominal composition of (Ce 0.2 Zr 0.2 Y 0.2 Sm 0.2 Nd 0.2 )O 1.6863 . In addition, the HEFOs have the best mechanical properties with Vickers hardnesses, flexural strengths and fracture toughnesses of 15.12 GPa, 101.1 MPa and 7.88 MPa-mm 1/2 , respectively, which have potential applications in high-performance structural materials.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2025
·
IF 4.3
Zehui Shang,Yinan Liu,Chunying Zhu,Taotao Fu,Xiqun Gao,Youguang Ma
The breakup of water-in-water droplets in a Y-junction microchannel was experimentally investigated, focusing on the unobstructed breakup mode due to its broad applicability. This process was divided into four stages: entering, squeezing, pinch-off, and filament rupture, based on the evolution of the neck width and its thinning rate. In the entering stage, neck thinning accelerates with increasing dispersed-phase flow rate Q d , droplet length l 0 , and two-phase viscosity ratio λ , and slows down with increasing continuous phase flow rate Q c . In the squeezing stage, the minimum neck width follows a power-law relation with time. The thinning rate increases with higher Q d , l 0 , and λ , whereas increasing Q c inhibits thinning. In the pinch-off stage, neck width decreases linearly with time, and the thinning is enhanced by higher Q c , Q d , and l 0 , but remains nearly independent of λ . The filament rupture stage follows a power-law thinning trend, and exhibits similar parameter dependencies, though satellite droplets may form at high Q d and Q c , and show increased instability at low viscosity. These findings offer insights into neck dynamics and interfacial rupture in low interfacial tension systems.
研究领域:
流体力学
·
微流控技术
·
软物质物理
·
界面科学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）