CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Kangchuang Li,Hua Hao,Zhonghua Yao,Minghe Cao,Hanxing Liu
Sr(Nb 0.5 Ga 0.5 ) x Ti 1-x O 3 (x = 1 %, 2 %, 3 %, 5 %) (STNG) ceramics were synthesized in nitrogen atmosphere by a solid state method. All samples exhibited a cubic perovskite structure without secondary phase. With the increase of the co-doped concentration of Nb 5+ and Ga 3+ , the grain sizes increased firstly and then decreased. The STNG ceramic with x = 3 % exhibited a colossal permittivity (CP) of 24502 and a low dielectric loss of 0.012 at 1kHz and room temperature. Compared with those samples sintered in air, the samples sintered in nitrogen atmosphere have a higher dielectric constant with lower dielectric loss. The phase structure, surface morphology, element distribution, element valence states and dielectric properties of STNG ceramics were investigated. And the mechanism of colossal permittivity was also explored, which indicated that the CP could be attributed to the formation of [ T i 4 + • e − V O • • − e • T i 4 + ] defect dipole.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2023
·
IF 10.9
Samuel Guemou,Liuting Zhang,Shuai Li,Yiqun Jiang,Tao Zhong,Zichuan Lu,Ren Zhou,Fuying Wu,Qian Li
The design of an excellent active catalyst to improve the sluggish kinetic and thermodynamic properties of magnesium hydride (MgH 2 ) remains a great challenge to achieve its practical application. In this study, a novel Ni-Nb/rGO nanocomposite catalyst was successfully prepared by one-spot hydrothermal and subsequent calcination methods. The novel Ni-Nb/rGO nanocomposite exhibits an exceptional catalytic effect on improving MgH 2 sorption properties. Specifically, the onset desorption temperature of MgH 2 + 10 wt% Ni-Nb/rGO composite is reduced to 198 °C, much lower than that of undoped MgH 2 (330 °C). Interestingly, the composite can release 5.0, 5.9, and 6.0 wt% H 2 within 10 min at 245, 260, and 275 °C, respectively. Furthermore, the dehydrogenated MgH 2 + 10 wt% Ni-Nb/rGO composite starts to absorb hydrogen even at room temperature with approximate 2.75 wt% H 2 uptake at 75 °C under 3 MPa H 2 pressure within 30 min and exhibits excellent stability by maintaining 6.0 wt% hydrogen content after 20 cycles at 300 °C. Chou's model suggests that the de/hydrogenation kinetics of Ni-Nb/rGO-modified MgH 2 switches from surface penetration model to diffusion model at lower temperatures. Additionally, the activation energies ( E a ) for the de/hydrogenation of MgH 2 + 10 wt% Ni-Nb/rGO are reduced to 57.8 kJ/mol and 33.9 kJ/mol, which are significantly lower than those of undoped MgH 2 . The work demonstrates that the addition of a novel ternary Ni-Nb/rGO catalyst is an effective strategy to not only boost the sorption kinetics of MgH 2 but also maintain its cycling property.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2019
·Vol. 30
·期 15
·14528-14537
·
IF 2.195
Zeng Yuan,Li Zhicheng,Shao Junming,Wang Xianchi,Hao Wenbin,Zhang Hong
Cu/Nb doped YFeO 3 ceramics were synthesized through wet chemical method followed by traditional ceramic sintering technology. The phase component and electrical properties of the ceramics were investigated. The XRD pattern shows that all the prepared ceramics have the orthorhombic perovskite structure with space group of P nma . The XPS analysis demonstrates the existence of Fe 2+ and Fe 3+ in the ceramics. The temperature dependence of resistivity indicates that YFeO 3 -based materials have a characteristics of negative temperature coefficient (NTC) of resistivity. The room temperature resistivities (306–1.52 × 10 5 Ω cm) and temperature sensitivity B values (2693–5395 K) can be effectively adjusted by changing the contents of Cu- and Nb- ions. According to the analysis of complex impedance spectra at various temperatures, the NTC characteristic could be attributed to grain effect and grain boundary effect. The possible conduction mechanisms are propose to hopping conduction and band conduction in grain, and thermal activation transport of charge carries in grain boundary.
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
·
IF 9
Yanping Yang,Shengchen Li,Shunli Shi,Jie Hu,Zexi Xuchen,Shunmin Ding,Dan zhao,Shengjun Deng,Weiming Xiao,Shuhua Wang,Chao Chen
Manganese oxide (MnO x ) catalysts are promising for low-temperature NH 3 -Selective Catalytic Reduction (NH 3 -SCR) with their superior catalytic performance. However, the presence of alkali metals in flue gases, particularly potassium (K), leads to catalyst deactivation and limits their industrial application. This study investigates the synergistic effects of Ce and Nb doping on the K resistance and low-temperature NH 3 -SCR activity of MnO x . The surface acidity and redox properties of MnO x were modulated by Ce and Nb modification. In addition, the phase structure, surface state and active sites of the catalysts were characterized before and after K poisoning. The results indicated that Nb 0.05 Ce 0.05 MnO x exhibited exceptional low-temperature performance, achieving over 90 % NO conversion at 125-250°C, along with significant resistance to K poisoning·NH 3 -TPD and in-situ experiments revealed that the loss of acid sites is the primary cause of K poisoning. The mechanism follows the L-H mechanism with L-acid sites as the main active sites on the catalyst surface and bridging nitrate as the key intermediate state. This research provides valuable insights into enhancing the industrial applicability of MnO x- based catalysts for low-temperature denitrification.
研究领域:
催化化学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOLID STATE ELECTROCHEMISTRY
·
2021
·Vol. 26
·期 2
·449-456
·
IF 2.647
Liu Shanshan,Li Chenyao,Wang Dongxin,Li Junyi,Yuan Rui,Che Yusi,He Jilin,Song Jianxun
In this research, the reduction mechanism of Nb(V) under various [F − ]/[Nb n+ ] ratios ( α ) was investigated by a series of electrochemical techniques, such as square wave voltammetry (SWV) and chronopotentiometry (CP). We previously studied the electrode reduction process of Nb(V) and revealed that was Nb(V) → Nb(III) → Nb(I) → Nb in NaCl-KCl molten salt. It was found in this research that the electrode reduction process of Nb(V) ion was shortened to Nb(V) → Nb(III) → Nb when α was equal to 1.0; furthermore, the electrode reduction process of Nb(V) ion transforms to Nb(V) → Nb(IV) → Nb when α was greater than or equal to 5.0. Moreover, the reaction mechanism was also discussed in this work. Metallic niobium was collected on a molybdenum electrode under the condition of higher fluoride content after electrolysis in the melt.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
ENERGY & FUELS
·
2025
·
IF 5.3
Jiapeng Lu,Chen Yan,Xin Min,Yangai Liu,Ruiyu Mi,Xiaowen Wu,Wei Wang,Zhaohui Huang,Minghao Fang
Nickel-rich layered LiNi0.8Co0.1Mn0.1O2 holds significant potential as a commercially viable cathode material. However, its widespread application is still hindered by inherent challenges, including poor structural stability, cycling performance, and rate capability. This study presents an Nb/Al codoped Li(Ni0.8Co0.1Mn0.1)0.98Nb0.01Al0.01O2 single-crystal ternary cathode material developed to overcome these challenges. The Nb and Al dopants are uniformly distributed throughout the material, resulting in the formation of an α-LiAlO2 protective layer on the surface. This protective layer effectively reduces electrolyte degradation and facilitates Li+ diffusion. Additionally, some of the TM-O bonds are replaced by Nb–O and Al–O bonds, which minimizes the intermixing of Li+ and Ni2+, thus improving the stability of the layered structure. The Nb/Al codoped nickel-rich single-crystal ternary cathode material exhibits superior cycling stability and rate performance compared to the undoped material. After 200 cycles at 1 C within the voltage window of 2.75–4.5 V, the NA-SNCM delivers a specific capacity retention rate of 76.11% (133.65 mA h g–1). Notably, the undoped counterpart displays severe microcracking, whereas the doped samples maintain intact crystallinity.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
HYDROMETALLURGY
·
2026
·
IF 6.3
Gengjin Zhang,Yanfang Huang,Longfei Jia,Tianze Chen,Yizhuang Wang,Shengpeng Su,Wenjuan Wang,Hu Sun,Guihong Han
Novel peroxo-complexation strategy was used to purify Nb-rich solution. • NbOF 5 2− transformation to NbO 2 F 5 2− greatly lowers its binding energy with MIBK. • Selectivity coefficient for Sb over Nb was enlarged by over 2300 times. • Nb 2 O 5 product met the high-purity specifications regarding Ta and Sb impurities. The efficient separation of Ta and Sb from Nb in hydrometallurgical processes remains a significant challenge due to their similar chemical behaviors. In this study, a novel peroxo-complexation strategy was introduced to enhance the selectivity of methyl isobutyl ketone (MIBK) extraction in an HF-H 2 SO 4 system. With the addition of H 2 O 2 , the extraction efficiencies of Ta and Sb reached 99.6% and 99.7%, respectively, while the co-extraction of Nb was only 2.32%. The selectivity coefficients of Sb/Nb and Ta/Nb significantly increased from 0.63 and 34.7 to 1461 and 6501, respectively. Stepwise stripping using H 2 SO 4 and pure water effectively recovered Nb and Ta/Sb from the loaded organic phase. Raman spectroscopy and quantum chemical calculations elucidated the mechanism of the enhanced separation selectivity. The peroxo-ligand selectively coordinates with Nb to transform it from NbOF 5 2− to NbO 2 F 5 2− , thereby weakening the negative surface potential of the fluorine atoms bonded to Nb. The binding energy between Nb ions and MIBK decreases from −172 kJ mol −1 to −104 kJ mol −1 , and thus the disparity in the affinity of Nb ions and Ta/Sb ions for MIBK is magnified. Overall, this peroxo-coordination approach provides an efficient and simple pathway for the effective purification of Nb solutions. Download: Download high-res image (176KB) Download: Download full-size image
✓ 已验证
产品关联
DOI
高影响因子
Journal of Energy Storage
·
2026
·
IF 10.7
Junming Han,Chunbo Guo,Fangyu Hao,Zihao Cai,Hao Zheng,Zeyi Jiang,Nien-Chu Lai
A high-purity Li 3 InCl 6 electrolyte is synthesized via a facile room-temperature liquid-phase method. • Nb 5+ doping induces lattice distortion and increases lithium vacancy concentration. • The Nb-Doped electrolyte achieves a high ionic conductivity and excellent electrochemical stability. • The assembled all-solid-state lithium battery delivers superior rate capability and long cycling life. Halide solid electrolytes hold great promise for all-solid-state lithium batteries (ASSLBs), yet achieving fast Li + transport and high electrochemical stability through scalable synthesis remains challenging. Herein, we report a facile wet-chemical route to synthesize Nb-doped Li 3 InCl 6 solid electrolytes, where a stepwise slow drying and thermal treatment protocol is adopted to regulate crystallization kinetics. By optimizing the solvent and dopant concentration, the 10% Nb-substituted sample (LIC Nb 1 ) prepared in ethanol shows optimal performance. Structural refinement and spectroscopic analysis reveal that aliovalent Nb 5+ creates Li vacancies and optimizes local lattice environments, promoting fast Li + conduction. Accordingly, LIC-Nb 1 exhibits a room-temperature ionic conductivity of 0.95 mS cm −1 , more than twice that of pristine LIC(Et) (0.44 mS cm −1 ), with a lower activation energy of 0.31 eV and enhanced electrochemical stability. ASSLBs based on LIC-Nb 1 delivers substantially improved rate capability and cycling stability relative to pristine LIC-based cells. At 30 °C, the LIC-Nb 1 -based cell shows stable charge/discharge behavior over 2–4.4 V (vs. Li/Li + ), affording an initial discharge capacity of 182.4 mAh g −1 , and an initial Coulombic efficiency of 91.02%. Under the more demanding rate and prolonged cycling evaluations conducted at 60 °C, the capacity retention of LIC-Nb 1 -based cell after 30 cycles at 0.1C under 100% depth of discharge reaches 83.5%, compared with 66.8% for the LIC(Et)-based counterpart. This work systematically clarifies the solvent effect on the crystal structure and ionic conductivity of LIC electrolytes, proposes a crystallization kinetics modulation strategy to eliminate structural defects, and validates the practical application potential of Nb-doped LIC electrolytes in high-voltage ASSLBs. These findings highlight the integrated strategy of kinetic regulation and heteroatom doping as an effective strategy for engineering high-performance halide solid electrolytes toward advanced all-solid-state lithium batteries. Download: Download high-res image (226KB) Download: Download full-size image
✓ 已验证
DOI
高影响因子
Molecular Catalysis
·
2026
·
IF 4.3
Dandan Zuo,Wuyu Wang,Miaojia Song,Peng Zheng,Sa Li,Qi Zhang,Xinghua Zhang,Longlong Ma
A ternary Cu-Nb/Al-MCM-41 catalyst achieves 99.60 % 2-methylfuran selectivity at 160 °C under atmospheric H2. • Al incorporation enhances metal dispersion and generates balanced Brønsted-Lewis acidity for controlled C O hydrogenolysis. • Nb promotion enables efficient H2 activation and strengthens Cu-Nb interfacial electronic coupling. • The catalyst exhibits excellent long-term stability and can operate continuously in a fixed bed for 500 h. The selective hydrodeoxygenation (HDO) of furfural (FAL) into 2-methylfuran (2-MF) is a crucial transformation for upgrading lignocellulosic biomass into liquid fuels. Herein, a series of Cu-Nb catalysts supported on mesoporous MCM-41 were developed. Over the optimized Cu-Nb/Al-MCM-41 catalyst, FAL was completely converted and the selectivity of 2-MF was 99.60 % at only 160 °C under ambient hydrogen pressure. Structural analyses revealed that Al incorporation reinforced metal-support interactions, enhanced Cu dispersion, and producing moderate Brønsted-Lewis acid sites, which synergistically facilitated hydrogen transfer and selective C O bond cleavage. In situ DRIFTS and XPS measurements confirmed a tandem hydrogenation-dehydration pathway proceeding via furfuryl-alcohol (FOL) intermediates, where Nb promoted H 2 activation and Al-derived acid centers accelerated dehydration at interfacial Cu-Nb-Al sites. The catalyst maintained high activity and selectivity during 500 h time-on-stream in a fixed-bed reactor, although slight deactivation was observed after prolonged operation. These findings establish a clear structure-function correlation between electronic modulation and acid-metal synergy, offering a sustainable strategy for efficiently producing furan-based biofuels under mild conditions. Download: Download high-res image (291KB) Download: Download full-size image
✓ 已验证
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2026
·Vol. 109
·期 6
·e70904
·
IF 4.2
Xinzi Zhong,Quanneng Zhang,Ji Zou,Keyu Gong,Zhipeng Zhang,Jingjing Liu,Huayue Liang,Shuaihang Qiu,Weimin Wang,Zhengyi Fu
Multicomponent oxide ceramics yield great promises in next-generation thermal protection systems according to their high potential for thermal stability and ablation resistance, but their protective mechanisms remain unclear. In this study, the five multicomponent A 6 B 2 O 17 (A = Zr, Hf; B = Nb, Ta) oxide ceramics with different atomic concentrations, respectively, at A- and B-sites, were prepared via a solid-state reaction with a rapid cooling process. Their phase, structural evolutions, and the properties under high-temperature treatment and dynamic ablations were investigated to reveal thermal stability and anti-ablation mechanisms. Only the (Hf 1/2 Zr 1/2 ) 6 (Ta 1/2 Nb 1/2 ) 2 O 17 with equal molar ratio both at A- and B-sites maintained the A 6 B 2 O 17 phase after heat treatment at 1773 K for 25 h; the other samples underwent phase separation behaviors. In addition, the (Hf 3/4 Zr 1/4 ) 6 (Ta 2/3 Nb 1/3 ) 2 O 17 ceramic showed excellent ablation resistance (∼2500 K, 100 s) with the thinnest oxide layer. This property is attributed to the formation of “skeleton-filler phase” protective composite layer, as the (Zr, Hf)O 2 “skeleton” owns high melting point and low volatility to resist thermal gas erosion, and the A n B 2 O 2n+5 family fills defects and hinders the penetrations of O 2 . This study expects to offer design for advanced thermal barriers suitable for the next-generation hypersonic vehicles and reusable spacecraft.
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Huicai Xie,Quanyi Liu,Xiaohua Luo,Shengcan Ma,Xinqiang Gao,Zhenxing Li,Zhaojun Mo,Jun Shen
For more practical applications, research on magnetic refrigeration has been gradually focused on developing refrigerants with large magnetocaloric effect (MCE) under low magnetic fields (≤2 T). EuTiO 3 exhibits considerable low-field MCE near ordering temperature, meanwhile the magnetic switch from antiferromagnetic to ferromagnetic (AFM-FM) in it provides the feasibility of improving the magnetocaloric performance. In this study, a series of Eu(Ti,Nb,M)O 3 (M=Cu or Zn) compounds were synthesized, and the crystal structure, magnetic properties together with cryogenic MCEs were investigated in detail. The co-substitution contributes to an FM coupling domination in all the compounds. Besides, significantly enhanced and giant low-field MCEs were detected in these compounds. Under the field change of 1 T, all the samples possess remarkable magnetic entropy change (>15 J·kg -1 ·K -1 ) around 5 K without hysteresis. The corresponding refrigerating capacities are calculated to be 68.0, 72.6, 76.0, and 69.6 J·kg -1 , respectively, exhibiting an increase of 149–178% than EuTiO 3 . The outstanding magnetocaloric performances make the Eu(Ti,Nb,M)O 3 (M=Cu or Zn) compounds competitive candidates for cryogenic magnetic refrigeration.
研究领域:
材料科学
·
凝聚态物理
·
功能材料
·
低温工程
·
磁学
✓ 已验证
DOI
高影响因子
IONICS
·
2026
·
IF 2.6
Yang Hao,Guo Jianling,Xue Juanjuan,Zhang Jingpeng,Liang Guangchuan,Wang Yong
This study successfully prepared high-density LiFePO 4 /C composite materials using a ternary co-doping strategy of Nb 2 O 5 , TiO 2 , and V 2 O 5 , combined with particle size optimization and control techniques. The substitution of Nb⁵⁺ for Li⁺ positions can widen the diffusion channels for Li⁺ and enhance its diffusion kinetics. The replacement of Fe²⁺ by Ti⁴⁺ can stabilize the crystal structure, reduce volume changes during charge-discharge processes, and improve cycling stability. The substitution of Fe²⁺ by V 4⁺ and the introduction of electron defects can increase electronic conductivity. The synergistic co-doping of Nb⁵⁺, Ti⁴⁺, and V 4⁺ increased the electrical conductivity of the LFP material from 2.0 × 10 − 1 to 2.6 × 10 − 1 S cm − 1 and the Li⁺ diffusion coefficient from 7.65 × 10 − 13 to 2.39 × 10 − 12 cm 2 s − 1 . Moreover, by optimizing the particle size distribution and adopting a non-uniform particle grading strategy, small particles can efficiently fill the gaps between large particles, reducing porosity and further increasing the compaction density. The final Li₀.₉₉₀Nb₀.₀₁₀Fe₀.₉₉₀Ti₀.₀₀₅V₀.₀₀₅PO₄ material achieved an industry-leading compaction density of 2.72 g cm − 3 under a pressure of 226 MPa. Electrochemical tests showed that the discharge capacities at 0.2 C and 5 C rates were 166.2 mAh g − 1 and 142.4 mAh g − 1 , respectively, and the capacity retention rate after 1000 cycles at 5 C was 91.34%. The assembled 14,500 cylindrical battery exhibited excellent volumetric energy density (0.2 C: 1166.27 Wh L − 1 , 1 C: 1109.62 Wh L − 1 ). This research provides an effective material design strategy for the development of high-energy-density lithium iron phosphate batteries.
✓ 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）