CHINESE JOURNAL OF CATALYSIS
·
2018
·
IF 3.525
Dawei He,Danhua Yuan,Zhijia Song,Yunpeng Xu,Zhongmin Liu
Zeolite synthesis in contemporary chemical industries is predominantly conducted using organic structure-directing agents (OSDAs), which are chronically hazardous to humans and the environment. It is a growing trend to develop an eco-friendly and nuisanceless OSDA for zeolite synthesis. Herein, choline is employed as a non-toxic and green OSDA to synthesize high silica Y zeolite with SiO 2 /Al 2 O 3 ratios of 6.5–6.8. The prepared Y zeolite samples exhibited outstanding (hydro)thermal stability at ultrahigh temperature owing to the higher SiO 2 /Al 2 O 3 ratio. The XRF, SEM, 29 Si-NMR and 13 Na+ results suggested that choline plays a structure-directing role in the synthesis of Y zeolite, while the feed molar fraction of Na + is a crucial determinant for the framework SiO 2 /Al 2 O 3 ratio and the crystal morphology.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
Journal of Advanced Ceramics
·
2021
·Vol. 10
·期 6
·1326-1337
·
IF 6.707
Li Ke,Rao Jiancun,Ning Congqin
The novel dental ceramics can be fabricated at lower temperatures when sol-gel derived lithium disilicate glass ceramics (LDGC) was used as an additive for yttria stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramics. The effect of LDGC on the sintering, mechanical, and translucent properties of Y-TZP ceramics was investigated in the present study. The results showed that the LDGC additive effectively improved the densification of Y-TZP at 1100 °C, which was much lower than the sintering temperature for pure Y-TZP. When sintered at 1100 °C, the Y-TZP with 1 wt% LDGC reached a relative density of 95.45%, and prossessed a flexural strength of 482.4 MPa and a fracture toughness of 5.94 MPa·m 1/2 . Moreover, its translucency was also improved. While, the addition of LDGC could result in an escape of yttrium atoms from the grain lattice of zirconia, which induced the tetragonal-monoclinic transformation of zirconia and abnormal growth of monoclinic grains. The escaped yttrium atoms diffused into the intergranular glass phase. The results indicated that the novel Y-TZP-LDGC ceramics has a great potential to be used for all-ceramic restorations.
研究领域:
材料科学
·
牙科医学
✓ 已验证
DOI
高影响因子
ACS Applied Nano Materials
·
2021
·
IF 5.097
Jianzhong Yu,Song Ye,Huazhen Liao,Xinling Xv,Deping Wang
Silver nanoclusters (Ag NCs) are emissive centers that are characteristic of high quantum yield, tunable emission, and large Stokes shift when confined inside zeolites, and their luminescence property is closely related to the cluster size, charge state, local environment, and extra activation. In this research, we evaluated the luminescence response of Ag NCs on the extra-framework cations by considering Na-type FAU-Y (NaY) as the parent zeolite. The extra-framework cations Na+ were partially substituted with Li+ or Ca2+ through the ion-exchange method and analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FT-IR) measurements, based on which a series of MYAg (M = Na, Li, Ca) zeolites were prepared through subsequent Ag+ exchange and thermal treatment under 600 °C for 2 h. The influence of extra-framework cations on the lattice parameter of the host zeolite, the exchange efficiency of Ag+, the formation ability, and the chemical state and luminescence property of Ag NCs was studied through the combination of structural and spectral measurements. This research indicated a flexible pathway for manipulating the luminescence property of Ag NCs, and the extra-framework cation-dependent luminescence property enables the FAU-Y zeolite to become a desirable host for the stabilization of Ag NCs to achieve highly efficient tunable emission.
研究领域:
材料科学
·
光化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Haowei Liu,Tao Zheng,Tianli Hui,Rui Zhang,Xianghai Meng,Wenshuai Zhu,Haiyan Liu,Zhichang Liu
Conversion of ethanol to high-value alcohols is an attractive approach for developing renewable biofuels, the key is to develop stable and high-efficient catalysts. In this work, based on the preparation strategy of heteroatomic Beta zeolites, a bifunctional Pt-Y/Beta catalyst was prepared by solid-state ion exchange and impregnation. Through characterization techniques such as TEM, NMR and XAS, it was confirmed that the Y species were incorporated into the framework of Beta zeolite by interacting with the silanol groups located at the defect sites, while the Pt species were confirmed to be present on the surface of the zeolite in the form of dispersed nanoparticles . The unique structure form and the favorable spatial proximity of the two metallic active sites lead to a synergistic catalysis, which enable a one-step conversion of ethanol to n-butanol with exceptionally high selectivity of 68 %. In situ DRIFT characterization, ethanol-TPD and relay experiment results show that in the ethanol to n-butanol reaction, the Pt species in Pt-Y/Beta catalyst serves as the active center for the dehydrogenation of ethanol and the hydrogenation of crotonaldehyde and crotyl alcohol, while the Y species is responsible for catalyzing the condensation reaction of acetaldehyde.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2024
·
IF 5.1
Tianfeng Zhou,Haotian Duan,Zhenzhong Li,Yu Jin,Hai Liu,Yuxia Pang,Hongming Lou,Dongjie Yang,Xueqing Qiu
Steric repulsive force is the main dispersion force between cement particles. In order to improve the dispersibility of polycarboxylate superplasticizers (PCEs), we designed and synthesized a new Y-type macromonomer (YPEG) with a molecular weight of Mw = 4100 Da. A long side chain-branched polycarboxylate superplasticizer (YPCE) was successfully synthesized by employing YPEG. Several common comb PCEs having the same side chain density but different lengths, such as PCE2400 and PCE4000, are employed to compare with YPCE for evaluating the dispersion performance. The results show that YPCE has a more excellent dispersion performance than the common PCEs under different water–cement ratios. Additionally, YPCE shows stronger water reduction for concrete. Furthermore, a dynamic light scattering study elucidates that YPCE can increase the adsorbed layer thickness from 5.6 to 7.9 nm, thus forming stronger steric hindrance. Simulations using molecular dynamics are conducted to investigate the influence of the conformational transformation of PCEs from comb-type to Y-type on the adsorption configuration and radius of gyration (Rg) of PCEs on calcium silicate hydrate surface. It is observed that the side chain of YPCE remains in an extended state, and Rg fluctuates little during the fitting process. This study provides a new strategy to enhance the steric hindrance of PCEs.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Haiyin Zhan,Chenxu Li,Zixuan Cao,Ruiren Zhou,Simiao Zhang,Ziyu Guo,Qixing Zhou
Y 2 O 3 is a cost-effective and environmentally friendly wide-band gap photocatalyst with extensive application potential. However, its limited ability to be excited by visible light restricts its practical uses. In this study, we coupled the narrow bandgap semiconductor AgI with Y 2 O 3 to form a Z-scheme heterostructure , significantly promoting its photocatalytic degradation activity. Characterization and experimental results demonstrated the formation of Y-O-Ag bonds through coupling with AgI, leading to an increase in oxygen vacancies in Y 2 O 3 , which promotes the chemisorption of H 2 O and O 2 . The Y-O-Ag bond introduction promotes electron transfer , improves hole utilization, and boosts energy transfer efficiency, thus promoting the efficient generation of ·OH and 1 O 2 . The photocatalytic degradation rates of RhB and o-nitrophenol by 7.5% AgI/Y 2 O 3 were 26.5 and 4 times higher than those of pure Y 2 O 3 , respectively. This study provides theoretical support for the Z-scheme heterojunction to improve photocatalytic activity and offers efficient solutions and practical design ideas for sewage purification.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Shi Ye,Jia-Yi Sun,Yu-Hong Han,Ya-Yun Zhou,Qin-Yuan Zhang
CsPbX3 (X = Cl, Br, I) perovskite quantum dots (QDs) have emerged as competitive candidate luminescent materials in the photoelectric fields due to their superior luminescence properties. However, the major drawback such as poor resistance to temperature, moisture, and irradiation of light, especially for the red QDs with I–, hinders their practical applications. Herein, we synthesized Mn2+-doped CsPbCl3 embedded in the cage of zeolite-Y as a new orange-red phosphor for the white light-emitting diode (WLED). The composites have significantly improved resistance to both elevated temperature and water over the bare Mn2+-doped QDs. The former exhibits little degradation whereas the latter shows apparent decline upon the irradiation of lights in the orange LED devices, which are fabricated by employing each material as a color-conversion phosphor coated on a 365 nm UV chip. A WLED is also achieved with a 365 nm UV chip coated with a CsPb(Cl0.5,Br0.5)3–Y blue phosphor and a CsPb0.75Mn0.25Cl3–Y orange phosphor. The device possesses a Commission Internationale de l’Éclairage coordinate of (0.34, 0.36), a correlated color temperature of 5336 K and a color rendering index of 81.
研究领域:
材料科学
·
光电领域
✓ 已验证
产品关联
DOI
PubMed
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2021
·Vol. 45
·期 42
·19903-19916
·
IF 3.591
SongSik Pak,KwangChol Ri,Chenmin Xu,Qiuyi Ji,Dunyu Sun,Chengdu Qi,Shaogui Yang,Huan He,MyongNam Pak
The g-C3N4/Y-TiO2 Z-scheme heterojunction photocatalysts were successfully synthesized. Powder X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy were used for characterization. The photocatalytic activity of the as-prepared samples was investigated via the degradation efficiency of rhodamine B (RhB) under visible-light irradiation, and 20 mg L−1 RhB was completely degraded in 90 min. The results showed that the photocatalytic degradation of RhB conformed to pseudo-first-order kinetic fitting, and the kinetic constants of g-C3N4/Y-TiO2 were 4.27 times higher than those of g-C3N4/TiO2 and 14.18 times higher than those of Y-TiO2, respectively. The enhanced photocatalytic activity of g-C3N4/Y-TiO2 was due to the formation of a Z-scheme heterojunction by Y at the g-C3N4/TiO2 interface. Formation of the Z-scheme heterojunction resulted in the suppression of photo-generated electron–hole pair recombination and the increase of their lifetimes, which was demonstrated by the transient photocurrent response, electrochemical impedance spectroscopy, and the time-resolved photoluminescence spectra. The superoxide radical and photo-generated holes played a dominant role in the photocatalytic degradation process of RhB by g-C3N4/Y-TiO2.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Polymer Chemistry
·
2016
·Vol. 7
·期 10
·1922-1930
·
IF 5.687
Yanzhi Xu,Mengxiang Zhu,Minjie Li,Ying Ling,Haoyu Tang
Water-soluble thermoresponsive poly(γ-4-methylbenzyl-L-glutamate) bearing Y-shaped (i.e., oligo-ethylene-glycol and alkyl groups, such as 1-butyl, 1-hexyl, or 1-dodecyl) and triazolium tetrafluoroborate side-chains (PMBLG-OEG7/Cm-BF4, m = 4, 6, and 12) have been prepared by nucleophilic substitution of poly(γ-4-methylbenzyl-L-glutamate)-oligo-ethylene-glycol conjugates (PMBLG-OEG7) and various 1-alkyl bromide and ion-exchange reactions of triazolium bromide and NaBF4. Poly(γ-4-chloromethylbenzyl-L-glutamate) (PCMBLG) was derivatized into poly(γ-4-azidomethylbenzyl-L-glutamate) (PAMBLG), followed by reaction with propargyl functionalized polyethylene glycol monomethylether 350 (Pr-OEG7) via a copper-mediated 1,3-dipolar cycloaddition to yield PMBLG-OEG7. PMBLG-OEG7/Cm-BF4, m = 4, 6, and 12) adopted an α-helical conformation and showed lower critical solution temperature (LCST)-type phase behaviors in aqueous solutions. The cloud point temperature (Tcp) was significantly decreased with an increase in polymer concentration and salt (e.g., NaBF4) concentration. Elongating the alkyl chain length can further decrease the Tcp.
研究领域:
高分子化学
·
生物材料科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Nano
·
2024
·
IF 15.8
Weijun Wang,Wenqing Wang,Yaxin Chen,Mengling Lin,Yan-Ru Chen,Ruijin Zeng,Tenghang He,Zhifa Shen,Zai-Sheng Wu
A major impediment to the clinical translation of DNA tiling nanostructures is a technical bottleneck for the programmable assembly of DNA architectures with well-defined local geometry due to the inability to achieve both sufficient structural rigidity and a large framework. In this work, a Y-backbone was inserted into each face to construct a superlarge, sufficiently rigidified tetrahedral DNA nanostructure (called RDT) with extremely high efficiency. In RDT, the spatial size increased by 6.86-fold, and the structural rigidity was enhanced at least 4-fold, contributing to an ∼350-fold improvement in the resistance to nucleolytic degradation even without a protective coating. RDT can be mounted onto an artificial lipid-bilayer membrane with molecular-level precision and well-defined spatial orientation that can be validated using the fluorescence resonance energy transfer (FRET) assay. The spatial orientation of Y-shaped backbone-rigidified RDT is unachievable for conventional DNA polyhedrons and ensures a high level of precision in the geometric positioning of diverse biomolecules with an approximately homogeneous environment. In tests of RDT, surface-confined horseradish peroxidase (HRP) exhibited nearly 100% catalytic activity and targeting aptamer-immobilized gold nanoparticles showed 5.3-fold enhanced cellular internalization. Significantly, RDT exhibited a 27.5-fold enhanced structural stability in a bodily environment and did not induce detectable systemic toxicity.
研究领域:
纳米技术
·
生物化学
·
分子生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COMPOSITES PART B-ENGINEERING
·
2022
·
IF 11.322
Zizhang Zhan,Wei Sun,Shuaishuai Zhang,Qingbo Wen,Hongbo Zhang,Xiang Xiong
A (AlCrMg) x (PO 4 ) y /MgO composite(APMC) was prepared based on the acid–base reaction between MgO and chromium aluminum phosphate solution for thermal protection and insulation applications at ultrahigh-temperatures up to 2400 °C. The compositions, formation mechanisms, microstructure, mechanical properties , thermal conductivity and ablation resistance of the composite were systematically investigated. The results show that the (AlCrMg) x (PO 4 ) y /MgO composite can be consolidated in different shapes at room temperature. The compressive strength of the as-prepared porous composites is higher than 20 MPa due to the macromolecular network structure, and it can be further improved to 42 MPa via thermal treatment. After ablation by an oxyacetylene flame at 2400 ± 70 °C for 60 s, the mass and line ablation rates of the composite were 0.0195 g/s and 0.43 × 10 −3 mm/s, respectively, which are comparable to those of ultrahigh-temperature ceramics. The excellent ablation resistance can be attributed to the in situ formation of a dense protective layer composed of spinel MgCr 2 O 4 and MgO phases. Interestingly, during ablation at 2400 °C the back-side temperature of the 15 mm-thick sample was lower than 130 °C, suggesting outstanding thermal insulation performance. The temperature gradient leads to the formation of a gradated porous structure which reduces the overall thermal conductivity of the composite.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Bin Fu,Yuqiong Zhao,Shipeng Zhang,Ying Wang,Jun Liu,Guojie Zhang
Nickel-based catalysts frequently encounter significant challenges in achieving both high CO 2 conversion and superior CO selectivity during reverse water gas shift (RWGS) reactions. To address this issue, we developed a facile strategy to prepare highly dispersed Ni/CeO 2 catalysts by forming Ce 1−x Ni x O 2−y solid solutions. Under conditions of 300–600 °C, 0.1 MPa, and a gas hourly space velocity (GHSV) of 40,000 mL g cat −1 h −1 , the 5Ni/CeO 2 -A catalyst exhibited outstanding selectivity, approaching 100 %. The RWGS reaction rate reached 1332 μmol CO g Ni −1 s −1 and maintained stable for 50 h almost without deactivation. The formation of Ce 1−x Ni x O 2−y solid solution uniformly disperses numerous Ni species in the CeO 2 lattice, effectively inhibiting Ni aggregation. This highly dispersed Ni weakens CO adsorption and facilitates its direct desorption without excessive hydrogenation. Moreover, the catalyst remains well-dispersed state even after reduction. The formed Ce 1−x Ni x O 2−y solid solution generates abundant oxygen vacancies on the catalyst surface, enhancing H 2 dissociation. The catalyst’s pore size distribution is also modified, creating stacked pores that favor reactant diffusion and expose more active centers. In-situ DRIFTS experiments demonstrate that Ce-OH plays a pivotal role in CO 2 adsorption on the 5Ni/CeO 2 -A catalyst, while the stabilization of bicarbonate and formate intermediates by the highly dispersed Ni further promotes catalytic performance. This study introduces a novel preparation method and provides valuable insights for designing Ni-based catalysts with exceptional CO selectivity.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）