INORGANIC CHEMISTRY
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2022
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IF 5.436
Xiaolong Chen,Xiangyu Chen,Xuesong Zhai,Yin Li,Wei Zhao,Wu Sun,Qinfang Zhang,Jing Feng
Internal OH– defects always cause significant depletion of excitation energy for low upconversion efficiency; however, preventing the incorporation of OH– into the crystal lattice is very difficult during the synthesis of upconversion crystals. In this work, red upconversion emission is dramatically enhanced in Er3+-sensitized hexagonal NaLuF4 (β-NaLuF4) microcrystals through a collaborative effect of ion exchange and Tm3+ doping. The ion exchange can not only maintain the morphology very well but also strongly reduce the internal OH– defects, which can enhance the upconversion luminescence due to improved excitation energy harvesting and red to green (R/G) ratio due to intense cross-relaxation. Doping of Tm3+ as an energy trapping center not only regulates the red emission output but also reduces the excitation energy loss. β-NaLuF4:Er,Tm microcrystals after ion exchange exhibit stronger red upconversion emission compared with β-NaYF4:Er,Tm and β-NaGdF4:Er,Tm counterparts. Moreover, fluorescent labeling of the fingerprint pattern printed from β-NaLuF4:Er,Tm microcrystals with stable and intense red fluorescence has been demonstrated under 980 nm excitation.
研究领域:
材料科学
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光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF RARE EARTHS
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2022
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IF 4.632
Xuesong Zhai,Yin Li,Wei Zhao,Wu Sun,Meng He,Jing Feng
In this work, monodisperse β-NaLuF 4 :Yb,Er microcrystals with intense upconversion emission were synthesized via a modified hydrothermal method . With the increase of reactant concentration, their production yield is increased obviously, and the upconversion emission intensity in β-NaLuF 4 :Yb,Er microcrystals is also enhanced significantly. The luminescence enhancement should be attributed to minimal internal OH − defects, validated by a combination of analytical X-ray diffraction (XRD), energy dispersive spectrum (EDS), and Eu 3+ structural probe measurements. We also reveal that high Na + :RE 3+ ratio in the β-NaLuF 4 :Yb,Er microcrystals prepared under Na + -rich reaction will arouse the increased repulsive energy of β-NaLuF 4 microcrystals between F − and OH − anions and then facilitate the substitution of large OH − ions by small F − ions under F − -rich reaction conditions. Minimal OH − concentrations can limit nonradiative relaxation and promote excitation energy harvesting for high upconversion efficiency. The presented results not only offer a facile method for the simultaneous production yield and luminescence intensity increase of β-NaREF 4 microcrystals, but also uncover a better insight into the upconversion emission alterations, which is favorable to broaden their practical applications.
研究领域:
材料科学
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光学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
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2024
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IF 6.7
Jinhui Song,Tianfu Zhang,Mengjiao Xing,Junfeng Zhou,Lu Tang,Jiaxin Xie,Zimin Peng,Wenyao Gu,Jianyu Tang,Suyao Liu,Tong Chang,Yi Liu,Yiwen Fang
With the potential application of biomass-derived feedstock upgradation to sustainable aviation fuels, it is essential to enhance the hydroisomerization performance of ZSM-22 zeolite while improving its resistance to residual oxygen-containing compounds. As the defect sites in the ZSM-22 zeolite, the abundant Si-OH groups are closely related to the catalytic performance and stability, serving as the main attack sites for the generated water. In this work, liquid-mediated defect-healing treatment is performed to heal Si-OH to Si-O-Si, leading to the enhancement of the crystallinity and pore connectivity without affecting the Si/Al, micropore volume, and morphology and preventing the micropores blockage and dealumination caused by conventional silylation and silication procedures. The outcome of the declined Si-OH groups is the reduction of the Lewis acid site without altering the Brønsted acidity. In the n-dodecane hydroisomerization, the catalyst obtained by the liquid-mediated defect-healing treatment route shows an increased conversion and isomer yield compared to the parent and healed catalysts prepared by other healing methods. This is mainly due to enhanced confinement of the micropore void, resulting in decreased apparent activation energy and reduced yield to multi-branched isomers prone to cracking. Furthermore, the healed catalyst exhibits improved resistance and structure stability in the hydroisomerization of feedstocks containing butanol. The work provides a prospective application of ZSM-22 zeolite in the hydroisomerization for complex and severe reactants through the essential Si-OH healing method.
研究领域:
催化化学
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材料科学
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能源化学
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
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2020
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IF 4.551
Yue Wei,Gang Li,Jiaxu Liu,Yanhui Yi,Hongchen Guo
The sluggish interfacial mass transfer usually hinders the achievement of high-efficiency catalytic transformation of biomass, especially for solvent-free immiscible reagent systems. Herein, amphiphilic hybrid Ti-containing catalysts in situ incorporated with organic groups (Cn-Ti-HMS) were developed for boosting biphasic solvent-free epoxidation of methyl oleate (MO) with H 2 O 2 . Benefiting from the mutual effect between organic/inorganic precursors, the resulting low-defect catalysts exhibit well-mediated surface hydrophilic/hydrophobic balance and porosity by incorporating alkyl groups. Such mediation effect exhibits two superiorities: i) accelerated adsorption of reactants by amphiphilicity; ii) boosted substrate or product diffusion by porosity property. As such, remarkably promoted catalytic properties were achieved when compared with conventional Ti-HMS. Typically, methyl-functionalized C1–Ti-HMS-50 displays the optimal catalytic performance with a 95% conversion of MO. Further mechanism study recognizes the dominant role of surface wettability and Si–OH defects content in influencing MO conversion and epoxidized MO selectivity.
研究领域:
催化
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材料科学
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化学工程
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环境化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）