CERAMICS INTERNATIONAL
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2024
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IF 5.1
Ying Li,Yong Hong Ma,Aihua Mao,Xiwei Qi
A series of transparent (1- y )La 2 O 3 –Ga 2 O 3 - y Sm 2 O 3 - x Eu 2 O 3 (where x = 0, 0.02, 0.04, 0.06, 0.08, 0.10, 0.12, 0.14, and y = 0, 0.04) were successfully synthesized using a containerless solidification process. Co-doping with Sm 3+ and Eu 3+ enhanced the energy absorption of Eu 3+ , notably improving the characteristic emission peak 5 D 0 - 7 F 2 of Eu 3+ . The peak emission intensity for y = 0.04 was observed at x = 0.08, attributable to the concentration quenching of Eu 3+ ions. As the concentration of Eu 3+ increased, the energy transfer effect on emission intensity diminished. Attributed to the energy transfer between Sm 3+ and Eu 3+ , Sm 3+ may primarily serve as the sensitizer, and Eu 3+ as the activator. According to the Dexter theory, which suggests that the interaction between activator ions and their adjacent ions is the primary mechanism of energy transfer and quenching among Eu 3+ ions and adjacent ions, an increase in Eu 3+ concentration leads to a decrease in the distance between Eu 3+ and adjacent ions, strengthening their interaction, and potentially inducing concentration quenching. Furthermore, with an increase in Eu 3+ concentration, the CIE chromaticity coordinates for the samples co-doped with Sm 3+ and Eu 3+ shifted significantly, enhancing the color purity of the emitted light and bringing it closer to the NTSC color standard coordinates (0.67, 0.33).
研究领域:
材料科学
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光学
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JOURNAL OF NON-CRYSTALLINE SOLIDS
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2024
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IF 3.2
Zhichao Jin,Zhongli Zhu
A series of SiO 2 -B 2 O 3 -ZnO-La 2 O 3 -BaO (SBZLBa) glasses doped with Dy 3+ and Eu 3+ were synthesized using the melt-quenching technique. Their optical characteristics and potential applications in W-LED devices were investigated. The structural effects resulting from doping the glass with Dy 3+ and Eu 3+ ions were elucidated through infrared spectroscopy and an examination of the physical properties. The variations in emission intensity within the fluorescence spectrum validated the sensitizing effect of Dy 3+ on Eu 3+ within the glass matrix. By manipulating the transitions of both Dy 3+ and Eu 3+ , the excitation wavelength was altered, enabling the realization of cool white, neutral white, and warm white luminescence, thus accommodating the diverse requirements for white light emission in lighting applications. After incorporating 1.0 mol% of Dy 2 O 3 and 0.8 mol% of Eu 2 O 3 , respectively, the glass exhibited CIE coordinates of (0.3332, 0.3535), positioning it within the white light spectrum and in close proximity to the ideal white light coordinates of (0.33, 0.33). The SBZLBa-Dy 2 O 3 –0.8Eu 2 O 3 glass exhibited a quantum yield of 5.98 %. It has been demonstrated through acid and alkali resistance tests that this glass possesses excellent chemical stability. Additionally, temperature-dependent emission spectra have revealed that the luminous intensity of the glass maintains over 85 % of its room temperature value at 185 °C, with Eα determined to be 0.2387 eV.
研究领域:
材料科学
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光学工程
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JOURNAL OF THE AMERICAN CERAMIC SOCIETY
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2026
·Vol. 109
·期 5
·e70871
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IF 4.2
Jingkai Zhou,Gang Qu,Yeli Chen,Dandan Huang
The isothermal phase equilibria of the Gd 2 O 3 –La 2 O 3 –ZrO 2 ternary system were experimentally determined at 1773 and 1573 K using a solid-phase reaction method. Continuous solid solutions of pyrochlore-type compounds (namely, Gd 2 Zr 2 O 7 and La 2 Zr 2 O 7 ) were confirmed across the ternary system, represented as La 2- x Gd x Zr 2 O 7 . The solubility limit of La 2 O 3 in the cubic fluorite ZrO 2 phase basically remains constant with decreasing temperature. The Gd 2 O 3 –La 2 O 3 –ZrO 2 ternary system was assessed by the CALculation of PHAse Diagrams (CALPHAD) method. The compound energy formalism (CEF) implemented was employed for thermodynamic descriptions of all phases within the CALPHAD method. A set of self-consistent thermodynamic parameters for the Gd 2 O 3 –La 2 O 3 –ZrO 2 system was derived.
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APPLIED CATALYSIS A-GENERAL
·
2018
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IF 4.521
Yajin Li,Jiaxiong Liu,Dehua He
The trans-esterification of glycerol and dimethyl carbonate (DMC) for the synthesis of glycerol carbonate was investigated over a series of Li-La 2 O 3 catalysts with different Li contents under mild reaction conditions. Li-La 2 O 3 catalysts were prepared by simple precipitation and impregnation methods, and characterized using ICP, XRD, BET, XPS, CO 2 -TPD and TEM techniques. It was found that the basicity of La 2 O 3 was obviously changed and the interaction between Li and La 2 O 3 occurred after doping Li component, and the catalytic activity of Li-La 2 O 3 was highly relevant to the strength and content of basic sites on the catalysts. Li doping influenced the crystal phase growth of La 2 O 3 , and also changed the exposed crystal planes of the Li-La 2 O 3 catalysts. The highest catalytic performance was obtained over 3.50Li-La 2 O 3 catalyst calcined at 600 °C for 5 h. The glycerol conversion of 94.4% and glycerol carbonate selectivity of 92.1% were obtained over this catalyst under the proper reaction conditions of 85 °C, 3 h, and the molar ratio of glycerol and DMC being 1/3 with using 0.1 g 3.50Li-La 2 O 3 catalyst.
研究领域:
化学工程
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催化材料科学
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
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IF 7.312
Jinshan Song,Nengwei Ma,Wenqing Chen,Jianmeng Chen,Qizhou Dai
In this study, a magnetic Fe 3 O 4 @SiO 2 @La 2 O 3 nano-catalyst with a core–shell structure was synthesized to improve the efficiency of catalytic ozonation of cinnamyl alcohol. The structure, morphology, and elemental composition of the catalyst were analyzed with the help of catalyst characterization methods. The mechanism of strengthened degradation efficiency and mineralization of cinnamyl alcohol in catalytic ozonation system in the existence of the catalyst were further discussed according to the analysis results. The results showed that the Fe 3 O 4 @SiO 2 @La 2 O 3 catalyst can not only greatly improve the degradation of cinnamyl alcohol, but also has good reusability and stability. And its economic efficiency is relatively good. The degradation rate of cinnamyl alcohol could reach up to 99.8% at 30 min, and the COD could be removed by 28.5% at 60 min with the help of the catalyst. The degradation efficiency of cinnamyl alcohol by ozone oxidation alone was only 52.1% at 30 min, and the COD removal rate was only 24.2% at 60 min in the same experimental conditions. Besides, the possible degradation pathway and degradation mechanism of cinnamyl alcohol were proposed according to the intermediate products detected by gas chromatography-mass spectrometry.
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Journal of Materials Research and Technology-JMR&T
·
2023
·
IF 6.4
Yuyu Liu,Wei Jiang,Zheng Chen,Quan Xu,Zhiliang Zhang,Jianying He
Due to the intrinsically ultrahigh cooling rate and thermal gradient during laser melting deposition (LMD), columnar-to-equiaxed transition (CET) of grains has been a significant challenge in titanium-based alloys. In this study, two strategies, including the optimization of processing parameters and the addition of ceramics particles, were utilized to promote the CET of Ti6Al4V. The optimal processing parameters of Ti6Al4V were confirmed by response surface methodology (RSM). The width of prior β grains effectively decreases under the minimum dilution of single track. Besides, different contents of TiB 2 and La 2 O 3 were added to Ti6Al4V powder and the in situ (TiB + La 2 O 3 )/Ti6Al4V composites were manufactured using the identified optimal processing parameters. In situ TiB whiskers segregating at the grain boundaries tailor the coarse columnar to equiaxed grains with La 2 O 3 particles dispersed in the composites. With increasing formation of the reinforcements, equiaxed grain size decreases from 23.3 to 11.9 μm. The ultimate tensile strength of the components was improved by 19.6% and 26.4% compared to that of Ti6Al4V. This work provides systematic solutions to suppress the coarse columnar grains and refine the microstructure for titanium-based alloys.
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ANALYTICAL CHEMISTRY
·
2023
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IF 7.4
Jiaxi Hu,Cheng Chen,Xiaobin Xie,Lichun Zhang,Hongjie Song,Yi Lv
With the intensification of explosive-based terrorism attack and environmental concerns, the innovation of high-efficiency and portable sensors for facile, rapid, and reliable monitoring of explosives has become one of the major demands in societies. Herein, a reliable and easy-to-use cataluminescence sensor system based on Dy3+ doping La2O3 nanorod catalysts has been developed for the identification and detection of six types of military explosive vapors, including homologous compounds and even isomers. The efficient discrimination is to make full use of the thermodynamic and kinetic information that can be extracted from the catalytic oxidation process of explosive molecules on various sensing materials, that is, the response signal and response time to generate the fingerprint of each target compound, while the rapid detection of the strategy can be manifested in response toward six military explosive vapors within 2.5 s and recover within 4 s. Meanwhile, the quantitative analysis of the explosives by the sensor system was realized based on 0.8%Dy:La2O3 with optimal catalytic activity, and the detection limits of NB, m-MNT, m-DNB, PNT, DNT, and TNT can reach 0.62, 0.49, 0.63, 0.38, 0.023, and 0.067 μg mL–1. In this research, we also constructed a novel sensor device and detection platform for explosive monitoring, which is of great significance for providing a new sensing principle for the efficient identification of explosives.
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PubMed
高影响因子
Catalysts
·
2023
·Vol. 13
·期 2
·298
·
IF 3.9
Haoting Yan,Yongwang Ren,Renkun Zhang,Feixiang Chang,Qinhong Wei,Jing Xu
It is a challenging task for selective hydrogenation of cinnamaldehyde (CAL) to hydrocinnamaldehyde (HCAL) without additional by-product formation. In this work, a La2O3supported high Ni content nanoparticle catalyst was prepared for CAL selective hydrogenation. Meanwhile, Co-La2O3catalysts were used as a reference catalyst. XRD, TEM, STEM-HAADF, XPS, and H2-TPR measurements were used to investigate the physicochemical properties of Ni-La2O3catalysts. The experimental results confirmed that the CAL conversion and HCAL selectivity were effectively promoted with the increase of Ni loading amounts. At a Ni/La molar ratio of four, a high HCAL selectivity of 87.4% was obtained at a CAL conversion of 88.1% under mild reaction conditions. The catalyst was recycled five times without activity loss. Combined with various characterizations, it could be inferred that the good hydrogen adsorption and dissociation capacity of Ni and the presence of a certain amount of oxygen vacancies on the La2O3support have a positive effect on the improvement of HCAL selectivity. This work provided an effective path to design transition-metal-based supported oxide catalyst for the cinnamaldehyde hydrogenation to hydrocinnamaldehyde.
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FUEL PROCESSING TECHNOLOGY
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2020
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IF 4.982
Zhige Zhang,Guofeng Zhao,Guican Bi,Yunyv Guo,Jun Xie
A monolithic silicon carbide foam (SiC-foam) structured nickel and lanthanum oxide (Ni-La 2 O 3 ) nanocomposite catalyst is developed via reducing the nickel oxide and lanthanum oxide (NiO-La 2 O 3 ) precursor that can be grown onto SiC-foam surface by depositing the needed citric acid gel followed by calcination at 750 °C. By taking the advantages of homogeneous component-distribution and strong Ni-La 2 O 3 interactions in the Ni-La 2 O 3 nanocomposites, this catalyst delivers much enhanced coke-depositing/Ni-sintering resistance than the unmodified counterpart of Ni-La 2 O 3 /alumina (Al 2 O 3 ) in the titled reaction. At 850 °C, a weight hourly space velocity (WSHV) is set as 24,000 mL CH4-CO2 g Cat −1 h −1 , methane/carbon dioxide (CH 4 /CO 2 ) conversions of 71/85% are initially achieved on the Ni-La 2 O 3 /SiC-foam catalyst followed by progressively decreased to 60/72% within 50 h (h), but remain almost unchanged for the next 50 h. On the contrary, the CH 4 /CO 2 conversions on the Ni-La 2 O 3 /Al 2 O 3 catalyst rapidly drop from 49/71% to 24/40% within only 25 h due to its serious Ni-sintering and coke deposition.
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MATERIALS CHARACTERIZATION
·
2026
·
IF 6.2
Peng-Cheng Cai,Xin-Wen Zhou,Xiao-Ming Dang,Zhen-Qi Shi,Guo-Hua Zhang
HERF creates hierarchical substructures with 66.3% LAGBs in ODS-W. • La 2 O 3 particles stabilize grain boundaries and impede dislocation motion. • The forged alloy reaches 1204 MPa UTS and 4.9% elongation at 200 °C. • Tensile BDTT is at or below 100 °C, with ductility retained to 600 °C. • CPFEM and TEM reveal continuous slip transfer and broad stress redistribution. Oxide-dispersion-strengthened tungsten (ODS-W) alloys are promising candidates for fusion energy and other extreme environments, yet their application remains limited by low-temperature brittleness, weak strain hardening and grain-boundary cracking. Oxide particles can pin grain boundaries and suppress coarsening, but excessive intergranular enrichment may also promote local stress concentration and intergranular fracture. Here we develop a multiscale microstructure design strategy that combines bottom-up powder synthesis with top-down high-energy-rate forging (HERF). Nanoscale W-1 wt% La 2 O 3 composite powders were prepared by spray drying, carbothermic pre-reduction and hydrogen deep deoxygenation, followed by low-temperature hydrogen sintering. Subsequent HERF reconstructed the W matrix into an elongated hierarchical structure containing dense sub structures and dislocation networks. The characteristic structural size decreased from 2.72 to 0.81 μm, while the fraction of LAGBs increased from 3.8% to 66.3%. The forged alloy showed measurable tensile ductility at 100 °C, indicating a brittle-to-ductile transition temperature (BDTT) below 100 °C. It achieved an ultimate tensile strength of 1204 MPa and a total elongation of 4.9% at 200 °C, while maintaining a favorable strength-ductility balance from 100 to 600 °C. Multiscale characterization combined with DFT, MD and CPFEM simulations shows that La 2 O 3 stabilizes the refined microstructure through grain-boundary pinning, while intragranular particles, forged substructures and dislocation networks promote dislocation storage, plastic-strain transfer and stress redistribution. These coupled effects suppress premature crack initiation and enable wide-temperature strength-ductility synergy in ODS-W. Download: Download high-res image (272KB) Download: Download full-size image
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ChemistrySelect
·
2023
·Vol. 8
·期 40
·e202302286
·
IF 2.1
Yaxin Gu,Yi Fang,Huayi Cai,Shaobo Yang,Song Yan,Rongjuan Zhang,Chaochao Cao,Chengchun Tang
Graphical Novel lanthanum modified porous BN composites (BN−La−X) were successfully prepared and applied to remove fluoride contamination in aquatic environment effectively. Fluorine contamination has caused great harm to humans and the environment. In this study, novel lanthanum modified porous boron nitride (porous BN) composites (BN−La−X) were successfully prepared and applied to remove fluoride from water. The results indicated that lanthanum was present on the surface of BN in the form of amorphous La 2 O 3 . BN−La-4 has excellent adsorption performance, and its removal of fluoride is much more effective than that of porous BN with good cyclic regeneration ability. In addition, the fluoride adsorption by BN−La-4 could reach adsorption equilibrium within 2 h and the adsorption kinetics was conformed to the pseudo-second-order model. The maximum adsorption capacity of BN−La-4 was calculated from the Langmuir model to be 80.04 mg g −1 , which was better than most related adsorbents. Furthermore, the presence of anions and pH values affected the removal of fluoride. The adsorption mechanisms were consisted of electrostatic attraction, ion exchange between hydroxyl and fluorine ions, and the formation of coordination complexes between lanthanide ions and fluoride ions. In summary, La 2 O 3 modified porous boron nitride composite is a promising adsorbent for the removal of fluoride contamination in aquatic environment.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2017
·
IF 3.582
Yiqun Jiang,Xiulin Fan,Xuezhang Xiao,Xu Huang,Meijia Liu,Shouquan Li,Hongwei Ge,Lixin Chen
Formic acid (FA, HCOOH), a convenient and safe hydrogen storage material, has the great potential for fuel cell applications . However, hydrogen generation of FA is inefficient in the presence of heterogeneous catalysts at relatively low temperatures, which remains a big challenge. Herein, La 2 O 3 -modified highly dispersed AuPd alloy nanoparticles (AuPd La 2 O 3 ) with small particle size have been successfully anchored on carbon nanotubes (CNTs) by a facile co-reduction route. Moreover, the catalyst exhibits excellent catalytic activity and 100% hydrogen selectivity for hydrogen generation in the formic acid/sodium formate (FA/SF) system with the initial turnover frequency (TOF) value of 589 mol H 2 mol −1 catalyst h −1 at 50 °C and 280 mol H 2 mol −1 catalyst h −1 even at room temperature (25 °C). The present Au 0.3 Pd 0.7 -(La 2 O 3 ) 0.6 /CNTs with superior catalysis on FA dehydrogenation without any CO generation at room temperature can not only pave the way for practical application of hydrogen storage system, but also can be extended to other catalysis system.
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