MINERALS ENGINEERING
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2026
·
IF 6
Shaoyang Chang,Boqi Wang,Mingjun Rao,Zhao Yang,Zhongshuai Jia,Haijiao Xie
This study proposes a crystal-phase-mediated strategy for the efficient synthesis of niobium carbide (NbC) from model niobium-bearing phases. By investigating the different carbonization behaviors of four representative niobium phases (niobium oxide, pyrochlore, columbite, and aeschynite), pyrochlore exhibited optimal carbonization capability due to its lowest activation energy (84.4 kJ·mol −1 ) and low Nb-O bond strength. We employed CaF 2 and Na 2 CO 3 as additives to convert refractory phases into a highly reactive pyrochlore intermediate (NaCaNb 2 O 6 F), achieving a conversion ratio of over 93% below 1100 ℃. This intermediate enables the efficient in situ synthesis of NbC with a carbonization ratio exceeding 92% at 1100 ℃ (based on selective leaching, estimated error ± 5%), about 200 ℃ lower than in direct carbonization. This additive-induced phase transformation pathway significantly lowers the energy barrier for NbC production, demonstrating a potential low-temperature pathway that may inform future strategies for the synthesis of niobium carbide, though further validation on natural ores is required.
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高影响因子
Journal of Materials Chemistry A
·
2026
·
IF 9.2
Yaning Liu,Da Yang,Rui Xu,Yijue Wang,Liuyi Hu,Tianqi Yang,Min Fan,Meiqing Feng,Jianping Xu,Zhen Xiao,Ruyi Fang,Jun Zhang,Xinhui Xia,Hui Huang,Xiayin Yao,Wenkui Zhang,Yang Xia
The advancement of all-solid-state lithium metal batteries (ASSLMBs) with high energy density is significantly constrained by the inherent drawbacks of solid polymer electrolytes (SPEs), such as low room-temperature ionic conductivity, inadequate mechanical strength to prevent lithium dendrite growth, and unstable interfaces between electrodes and electrolytes.To overcome these limitations, this study introduces a synergistic modification strategy for poly(ethylene oxide) (PEO)-based SPEs by incorporating calcium fluoride (CaF2), aiming to concurrently improve bulk electrolyte properties and interfacial stability. The introduction of CaF2 effectively inhibited the crystallization of PEO by steric hindrance and Lewis acid, which made the ionic conductivity of the electrolyte reach 8.49 × 10-5 S cm-1 at 40°C (70% higher than that of the original electrolyte) and the lithium-ion migration number increased to 0.34.The composite electrolyte also demonstrates improved mechanical robustness (yield strength of 1.61 MPa) and electrochemical stability window (with decomposition voltage elevated to 5.01 V), enabling a critical current density of 0.8 mA cm-2 . Theoretical and experimental investigations reveal that CaF2 promotes the formation of a hybrid solid electrolyte interphase (SEI) enriched with LiF and Ca-Li alloys, which guides uniform lithium deposition. As a result, Li symmetric cells achieve stable cycling over 1600 hours, and LiFePO4||Li full cells retain 98.1% of their initial capacity after 300 cycles at 0.5 C. This work offers a scalable pathway for designing dendrite-suppressing SPEs through dual optimization of bulk and interfacial characteristics.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
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IF 6.2
Yifan Zhang,Xianwei Hu,Fengguo Liu,Jiaxin Yang,Liyu Chen,Wenju Tao,Aimin Liu,Zhongning Shi,Zhaowen Wang
In the present study, the reaction process and reaction mechanism of the aluminothermic reduction of NaVO 3 to prepare aluminum-vanadium intermediate alloy were investigated by experimental analysis and quantum chemical calculations. The results of thermal analysis and isothermal experiments indicated that the aluminothermic reduction of NaVO 3 was a multi-step process and temperature played a critical role in this process. The aluminum-vanadium intermediate alloy was generated when the temperature exceeded 963 ºC, and it could be further separated from the reduction product after the addition of slag-forming agents (CaO and CaF 2 ) at 1600 ºC. Furthermore, an atomic-level insight into the reaction between aluminum and NaVO 3 was explored based on the electrostatic potential (ESP) analysis of the reactivity of NaVO 3 . The results showed that the aluminum atom first interacted with NaVO 3 to form an intermediate complex through electrostatic interaction , and then NaVO 3 was reduced to NaVO 2 under the continuous action of aluminum. Further, the newly formed NaVO 2 was consequently converted to aluminum-vanadium intermediate alloy under the continuous action of aluminum atoms. These theoretical results were essentially consistent with the experimental data, which provided a fundamental understanding about the reaction mechanism of NaVO 3 with Al. Moreover, the aluminothermic reduction of NaVO 3 also provided a feasible and environmentally friendly metallurgical approach for preparing aluminum-vanadium intermediate alloy.
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高影响因子
JOURNAL OF RARE EARTHS
·
2023
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IF 4.9
Daguang Li,Jiahao Cui,Yanhui Dong,Hao Cui,Dan Zhao,Weiping Qin
In order to improve the multi-ion cooperative transition, we proposed and exploited a novel nanoscale effect, namely the nanoshell effect in bulk materials. Based on the effect, an optimal material structure was designed by coating the surfaces of CaF 2 :Yb 3+ micron size particles with ZrO 2 . An about 2 times higher intensity of cooperative luminescence is observed upon laser excitation at 980 nm. Dynamical analysis exhibits that the novel effect plays a key role in improving the performance of cooperative transitions. Our results also suggest that the nanoshell effect in bulk materials is likely to be significant in some special cases, which have not been reported yet in the literature.
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高影响因子
ChemCatChem
·
2023
·Vol. 15
·期 5
·e202201352
·
IF 4.5
Qingpo Peng,Yongjun Jiang,Bei-Bei Xu,Xiuge Zhao,Sheng Dai,Ye-Feng Yao,Zhenshan Hou
Graphical Zr oxo cluster bifunctional catalyst : The Zr oxo cluster [Zr 6 O 4 (OH) 4 (HSCH 2 CH 2 COO) 12 ] 2 has been developed, and then the molecular catalyst with Lewis acid and Brönsted acid sites were attained by the oxidation of the sulfhydryl group of the Zr oxo cluster with H 2 O 2 . The resulting bifunctional catalyst showed a superior catalytic activity for alcoholysis of furfural to alkyl levulinates. A novel dodecanuclear Zr oxo cluster [Zr 6 O 4 (OH) 4 (HSCH 2 CH 2 COO) 12 ] 2 (ZrO-SH-10) has been constructed under the room temperature, followed by oxidation of the sulfhydryl group with H 2 O 2 to achieve a bifunctional catalyst with Lewis acid and Brönsted acid sites. The characterization of catalysts indicated that {Zr 6 O 4 } cluster core can be stabilized with a shell of carboxylate ligands, and the resulting ZrO-SO 3 H was formed as a discrete molecular catalyst, exhibiting superior activity and recyclability for the cascade conversion of furfural to alkyl levulinate by the integration of transfer hydrogenation and alcoholysis in n-butanol. The yield of n-butyl levulinate can achieve as high as 91 % under the optimum conditions. Meanwhile, no leaching of the active species was found, which confirmed the structure of the Zr oxo cluster was air and moisture-stable. On the basis of the studies on the reaction kinetics and isotope tracking, the reaction mechanism was proposed accordingly.
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高影响因子
FUEL
·
2022
·
IF 8.035
Huifa Zhang,Shaolin Wang,Huixian Zhang,Lingrui Cui,Fahai Cao
Ethyl levulinate (EL), as a potential fuel additive and versatile biomass-based platform molecule, has been the focus in the field of sustainable chemistry. In this contribution, a series of economic and environmental friendly biomass-derived P doped carbon catalysts were developed in this study for synthesis of EL from renewable furfural alcohol (FAL) in a hot ethanol medium. The carbon catalyst, P-C-800, synthesized via carbonizing the phytic acid at 800 °C, exhibited a good catalytic activity in alcoholysis of FAL to EL. The highest yield of EL could be 79.7% with a complete conversion of FAL at 140 °C in 6 h. Moreover, P-C-800 could be recovered efficiently and reused multiple times with sustained catalytic activity. It was revealed further by the detailed catalyst characterization and systematic evaluation of catalytic performance that both the acid content and surface area of the P-C-800 were crucial for the alcoholysis of FAL to EL.
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高影响因子
JOURNAL OF RARE EARTHS
·
2022
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IF 4.632
Yusheng Yang,Tuoyao Wang,Ran Zhao,Shuyan Zhang,Zengwu Zhao
Neodymium oxyfluoride has received much attention in the fields of anionic solid electrolytes , luminescent , catalytic and magnetic materials because of its structure combined advantages of rare-earth cations with F – and O 2– anions. In this work, neodynium oxyfluoride was synthesized by the reaction between neodymium oxide and four fluoride media with different fluoride ion activities . The synthesis processes in molten LiF–CaF 2 –NdF 3 , LiF–NdF 3 , NaF–CaF 2 -NdF 3 and NaF–KF–NdF 3 are observed in situ by a confocal scanning laser microscope. The expansion of neodymium oxide particle is observed in the LiF–CaF 2 –NdF 3 , LiF–NdF 3 , and NaF–KF–NdF 3 melts, and the growth of needle crystals on neodymium oxide particle is clearly observed in molten NaF–CaF 2 –NdF 3 . Based on scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analyses of products, neodynium oxyfluoride was successfully synthesized in the four fluoride media. The neodynium oxyfluoride generated in the LiF–CaF 2 –NdF 3 , LiF–NdF 3 , and NaF–KF–NdF 3 melts is a tetragonal structure. However, in molten NaF–CaF 2 –NdF 3 , neodynium oxyfluoride with a rhombohedral structure is formed. It is suggested that the substitution of Na(I) and Ca(II) for Nd(III) can transform NdOF from tetragonal structure to rhombohedral structure. The growth rate of needle crystals generated in molten NaF–CaF 2 –NdF 3 was calculated based on the result of a confocal scanning laser microscope, and it is found that the reaction kinetics of crystal formation is zero-order reaction. The effect of fluoride media on the structure and morphology of formed NdOF were evaluated by XRD, X-ray photoelectron spectroscopy (XPS) and SEM. The neodymium oxyfluoride prepared in the fluoride media with high fluoride ion activity has low binding energy of F 1s. The ratio of adsorbed oxygen to lattice oxygen for neodymium oxyfluoride prepared in molten LiF-NdF 3 is larger than those in the other three fluoride media, so it can have better catalytic performance.
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高影响因子
ENERGY
·
2022
·
IF 8.857
Yanwu Ji,Yunlan Sun,Baozhong Zhu,Jianzhong Liu,Yuxin Wu
Aluminum (Al) powder as an additive can enhance the specific impulse of propellants. However, it is hard to completely burn due to its aggregates in the combustion of propellants. To improve the combustion of Al powder, calcium fluoride (CaF 2 ) was added to micron-sized Al powder to form the Al/CaF 2 mixture, whose thermal behaviors, ignition and combustion performance, and combustion products were investigated. Micron-sized Al powder with CaF 2 addition can decrease its ignition delay time and increase its self-sustaining combustion time. The corresponding values can be decreased by more than 65% and increased by more than 16%, respectively. Compared with micron-sized Al powder, an obvious gas-phase combustion occurs in the Al/CaF 2 mixture. The agglomeration mechanism of Al combustion in the Al/CaF 2 mixture were analyzed. On the one hand, the uneven distribution of oxidant leads to a pressure difference during combustion to accelerate Al agglomeration; on the other hand, the melting-agglomeration-combustion process occurs because the melting temperature and the ignition temperature of Al have a big difference. In addition, an improved Al combustion mechanism was established.
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高影响因子
INTEGRATED FERROELECTRICS
·
2022
·
IF 0.836
Zhifen Fu,Chang Li,Chen Chen,Yubin She,Zhongyi Yang
low-fired Li2ZnTi3O8 ceramics were fabricated by a solid-state reaction method for developing LTCC applications. TLBBC mixed sintering aid was used to improve the sintering stability. X-ray diffraction analyses demonstrated that specimens corresponded well to the cubic crystal symmetry structure of Li2ZnTi3O8, accompanying with a little of impure phase Ca3Ti2O7 and LiBO2. The sintering temperatures of Li2ZnTi3O8 ceramics were lowered to 950 °C due to the formation of low melting point LiBO2. At x = 3, Li2ZnTi3O8 ceramics exhibited an microwave dielectric properties with εr = 21.0, tanδ = 5.76 × 10−4, Q × f = 14750 GHz, τf = −11.5 ppm/°C at 950 °C.
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高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Xuan Liu,Dian Zhang,Rongrong Ma,Yu Wang,Xiaofeng Yang,Yijun Liu
With the rapid development of hypersonic vehicles and broadband wave-transparent radome, Si 3 N 4 porous ceramics (Si 3 N 4 -PC) have attracted attention due to their excellent intrinsic properties of Si 3 N 4 and high porosity. However, its high porosity results in low strength and toughness, which are fundamental properties for radome. Reaction bonded (RB) Si 3 N 4 -PC has advantages of dielectric properties and cost over general phase transformation sintering (PTS) and sintered reaction bonded (SRB) Si 3 N 4 -PC while it has been neglected in recent years. In this study, RB and SRB Si 3 N 4 -PC prepared by non-aqueous gelcasting and the influence of Si powders ingredient on their properties are discussed in order to illuminate the potential of RB Si 3 N 4 -PC in wave-transparent materials. The results show that RB Si 3 N 4 -PC with dual-granularity ingredients of 5 μm & 45 μm produces a two-tier tissue of framework of coarse whiskers enhanced by a network of tiny whiskers. SRB Si 3 N 4 -PC evolves into a two-tier tissue of framework of columnar and rod-like grains joining together to brace each other. The two-tier microscopic tissue strongly reinforces and toughens the structure and results in higher σ F and γ wof . As a result, the RB and SRB Si 3 N 4 -PC of dual-granularity of 5 μm & 45 μm obtain the maximum σ F of 109.94 MPa and 119.56 MPa as well as maximum γ wof of 990.74 J m -2 and 1167.88 J m -2 , respectively. Furthermore, the ε′ and tanδ of RB and SRB Si 3 N 4 -PC of dual-granularity of 5 μm & 45 μm are about 4.20 and 4.52 as well as 7.01 × 10 -3 and 22.90 × 10 -3 , respectively. It is concluded that RB Si 3 N 4 -PC of dual-granularity has good mechanical and dielectric properties, which are favorable for radome.
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高影响因子
International Journal of Applied Ceramic Technology
·
2022
·Vol. 19
·期 4
·2083-2092
·
IF 2.328
Zixuan Chang,Zihe Li,Xinran Liu,Xu Zhang,Shikang Xiao,Yuhang Tian,Aijun Li,Jingde Zhang,Jianzhang Li,Guifang Han
Mullite-bonded porous SiC ceramics sintered in air by gelcasting are still challenges due to the high porosity induced severe oxidation of SiC, which results in the formation of large amount of detrimental cristobalite phase. Here in this work, small amounts of Y 2 O 3 and CaF 2 were added in SiC and Al(OH) 3 raw materials as sintering additives for the in situ growth of mullite reinforcement. This additive system promoted the reaction between oxidation-derived SiO 2 from SiC and Al 2 O 3 decomposed from Al(OH) 3 to mullite phase. Almost no cristobalite phase was detected when sintered at 1450℃/2 h with CaF 2 addition of more than 2.0 wt%. Mullite whisker reinforcement was in situ formed due to the gas reaction mechanism caused by CaF 2 addition. Thus obtained porous SiC ceramics exhibited a flexural strength of 67.6 MPa at porosity of 41.3%, which maintained exceeding 36 MPa after 8 h corrosion in 10 wt% NaOH 80℃ solution, being the best performance up to now. This high performance of porous SiC was attributed to the additive induces proper phase control and in situ formation of whisker-like mullite reinforcement.
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高影响因子
Optical Materials Express
·
2022
·Vol. 12
·期 10
·4117-4132
·
IF 3.074
Zihan Zhao,Zihan Zhao,Ran Zhang,Ran Zhang,Hao Song,Yanjie Zhang,Yanjie Zhang,Yanjie Zhang,Xiuping Wu,Desheng Li,Bing Li,Bing Li
As blue emitting component in phosphor-converted white-light-emitting-diodes (pc-wLEDs) encapsulated with near-ultraviolet (NUV) chips, Eu2+ activated fluorapatite structure phosphors play key roles because of strong structural stability and excellent photoluminescent properties. A series of M5(PO4)3F: Eu2+ (M = Ca, Sr) samples have been newly prepared by deposition-precipitation process (DP) and exhibited a 6.7-fold enhancement of photoluminescent (PL) intensity due to the highly dispersed Eu2+ luminescence centers when compared with the reference samples synthesized via traditional solid-state reaction method (SSR). Detailed analysis of crystal field around Eu2+ and the nonlinear fitting of PL spectra concludes that Eu2+ activators with the 4f6 → 4f75d transition preferentially replace Ca1 in 4f symmetry sites leading to a fitted peak at 446 nm and the other sites of 6h are contributed to the 479 nm emitting of Eu2+ ions. Remarkably, tunable chromaticity of DP-M5(PO4)3F: Eu2+ with high color purity (97.79%) retains steady photoelectric converting and full width at half maxima (FWHM) of 46 nm in the device of DP-FAp: 0.03Eu2+@365 nm LED under diverse driving currents, which perfectly satisfies the requirements of excitation light source for oral photocuring materials. Further, the 123.4% color gamut of National Television System Committee (NTSC) standard is efficiently obtained by matching Sr5(PO4)3F: Eu2+, CsPbBr3 and Lu3Al5O12: Mn4+ phosphors with a 365 nm chip (1 W) to achieve high-quality white light (CRI value reaches to 86, CCT is 7107 K and CIE chromaticity coordinate arrives at (0.292, 0.376), indicating a potential candidate for dentistry curing light and high-quality NUV excited pc-wLEDs.
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高影响因子
危险品化学品经营许可证（带存储）