CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Yan Xue,Wenye Deng,Yi Liu,Jinyang Li,Ni Ai,Pengjun Zhao,Aimin Chang,Huimin Zhang,Yongxin Xie
A series of LaAl 1- x Nb x O 3 (0 ≤ x ≤ 0.100) samples were synthesized via the solid phase method. Characterization techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) confirmed the formation of a solid solution in LaAl 1- x Nb x O 3 (0 ≤ x ≤ 0.100) materials without the emergence of additional phases following Nb doping. Transmission electron microscopy (TEM) revealed distinct lattice fringes with a d value of 0.274 nm, corresponding to the (110) plane of LaAlO 3 (PDF #82–0478). The introduction of Nb dopant caused distortions in the cell parameters of LaAlO 3 due to ionic radius size effects, changes in Nb valence, fluctuations in oxygen vacancy concentration and Coulomb forces. Specifically, the lattice exhibited a shrinkage for 0 ≤ x ≤ 0.025, expansion for 0.025 < x ≤ 0.075, and subsequent shrinkage for 0.075 < x ≤ 0.100. Resistance measurements indicated that LaAl 1- x Nb x O 3 (0 ≤ x ≤ 0.100) materials exhibited favorable negative temperature coefficient (NTC) characteristics in the temperature range of 600 °C–1400 °C. Hall measurements revealed that the materials functioned as P-type semiconductors with hole carriers, and Nb doping enhanced carrier concentration. Aging tests demonstrated that the aging drift rate of LaAl 0.9 Nb 0.1 O 3 could be as low as 0.906% after aging it at 1000 °C for 500 h, a crucial parameter for practical applications of LaAl 1- x Nb x O 3 (0 ≤ x ≤ 0.100) materials in high-temperature NTC applications.
研究领域:
材料科学
·
电子工程
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产品关联
DOI
高影响因子
iScience
·
2023
·
IF 5.8
Ying Zhang,Yuying Wan,Xiaoxu Liu,Kai Chen,Ke Chu
Electrocatalytic reduction of nitrite to ammonia (NO 2 RR) is considered as an appealing route to simultaneously achieve sustainable ammonia production and abate hazardous nitrite pollution. Herein, atomically Nb-doped NiO nanoflowers are designed as a high-performance NO 2 RR catalyst, which exhibits the highest NH 3 -Faradaic efficiency of 92.4% with an NH 3 yield rate of 200.5 μmol h -1 cm -2 at -0.6 V RHE. Theoretical calculations unravel that Nb dopants can act as Lewis acid sites to render effective NO 2 - activation, decreased protonation energy barriers, and restricted hydrogen evolution, ultimately leading to a high NO 2 RR selectivity and activity.
研究领域:
材料科学
·
环境科学
·
催化化学
✓ 已验证
DOI
PubMed
高影响因子
Inorganic Chemistry Frontiers
·
2018
·Vol. 5
·期 5
·1126-1132
·
IF 5.106
Congjie Lv,Yi Peng,Jing Yang,Xiaochuan Duan,Jianmin Ma,Taihong Wang
Nb-Doped LiNi0.4Co0.2Mn0.4O2 (Nb-NCM) nanobelts have been successfully fabricated for the first time through a facile electrospinning method by the delicate control of PAN pyrolysis and Nb-NCM formation (including nucleation and subsequent growth processes). According to the experimental evidence from temperature-dependent characterization and isolation of the intermediates, the formation of nanobelts undergoes a morphology evolution from nanofibres to nanotubes, and finally to the nanobelts composed of subunit nanoparticles. When used as a cathode for lithium-ion batteries, the as-electrospun Nb-NCM nanobelts exhibit superior electrochemical performances, which could be attributed to their unique features, such as their 1D nanostructure, well-crystallized nature and Nb-doping. These features can improve the ionic conductivity of Nb-NCM nanobelts and stabilize the electrode/electrolyte interface. Therefore, the 1D Nb-NCM nanobelts developed in this study not only provide an excellent model to investigate the fabrication of multi-element oxides using the electrospinning method, but also open up a facile route for designing 1D layered cathodes with a complex component for high performance lithium-ion batteries.
研究领域:
材料科学
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纳米技术
·
电化学
·
能源存储
·
无机合成
✓ 已验证
DOI
高影响因子
Surfaces and Interfaces
·
2025
·
IF 6.3
Xu Xiang,Yi Zhu,Junding Zheng,Ying Li,Tao Zhang,Ju Gao,Hongfang Zhang
Harnessing contact electrification to drive redox reactions offers a promising, illumination-independent route for wastewater remediation. However, the interfacial mechanisms governing tribocatalytic efficiency remain unclear. Here, Nb-doped SrTiO₃ (0.25–2 mol %) was systematically investigated under Tribo-, Light-, Dark-, and combined Tribo-Light conditions to elucidate the role of electronic structure and field screening on performance. Mott–Schottky and Kelvin probe force microscopy (KPFM) analyses reveal that increasing Nb content raises the Fermi level and compresses the Debye screening length (λ D ) from ≈ 6 nm (0.25 % Nb) to ≈ 4.5 nm (2 % Nb). EIS confirms this shortening through reduced space-charge resistance, while zeta-potential measurements show consistently moderate negative values (≈ –25 to –30 mV), excluding adsorbed species as the dominant factor. An optimal λ D window of 5.5–6.0 nm at 0.25–0.5 % Nb balances donor concentration and interfacial field penetration, enabling efficient electron extraction and radical generation. Consequently, 0.25 % Nb–SrTiO₃ achieves 90 % RhB degradation in 24 h (Tribo-only) and complete MB removal within 2 h (Tribo-Light), whereas 2 % Nb over-screens the surface field and suppresses reactivity. These findings identify the Debye length as a quantitative descriptor for tribocatalytic design, providing a mechanistic basis for engineering high-efficiency, bias-free catalysts for environmental remediation.
研究领域:
材料科学
·
催化
·
环境工程
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表面科学
·
能源材料
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2019
·Vol. 103
·期 5
·2970-2974
·
IF 3.094
Honghua Liu,Bin Du,Yanhui Chu
The polymer-derived-ceramic (PDC) route has been widely used to fabricate the transition-metal carbides (TMCs). Previously reported works focused mainly on the synthesis of the single or binary TMCs, while the synthesis of the ternary or more component TMCs was rarely reported. Herein, a class of the ternary TMCs, namely (Nb 1/3 Zr 1/3 Ta 1/3 )C solid-solution ceramics, was successfully synthesized via PDC route for the first time. The as-synthesized ceramics exhibited the particle-like morphology with an average particle size of ~250 nm and showed a single rock-salt crystal structure of metal carbides. At the same time, they had high compositional uniformity from nanoscale to microscale. In addition, they possessed low-oxygen impurity content of 0.79 wt% and moderate-carbon impurity content of 8.98 wt%. Such work provides a novel route to fabricate the ternary or more component TMCs.
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS & DESIGN
·
2017
·
IF 4.364
Puhong Wen,Lili Ai,Taotao Liu,Dengwei Hu,Fangyi Yao
The regular orthorhombic Nb 2 O 5 (O-Nb 2 O 5 ) rectangle nanosheets dominantly exposed (010) facet are synthesized by a hydrothermal topological reaction with a precursor of K 4 Nb 6 O 17 ·4.5H 2 O (KNbO). The structure and morphology of the samples obtained at different temperatures and pH values of reacting solution are investigated. The results suggest that there are two topological reactions in this process. One is the acid-exchanging reaction transforming into H 4 Nb 6 O 17 ·3H 2 O (HNbO) nanosheets from KNbO rectangle nanosheets , and the other is dehydration reaction transforming into O-Nb 2 O 5 rectangle nanosheets from HNbO nanosheets. And the {010} facets of O-Nb 2 O 5 crystal are transformed from the {010} facets of HNbO crystal in the ingenious topological reaction. The photoelectric performance of the obtained O-Nb 2 O 5 nanosheets is evaluated by decomposing water to H 2 under 370 nm UV light illumination and measuring the accompanying photocurrent . The photocurrent density is 680 nA·cm − 2 generated by splitting water with O-Nb 2 O 5 nanosheets as photocatalyst , and it is 4.3 times of the contrast sample. The result indicates that the (010) facet of O-Nb 2 O 5 is one of the highest photocatalytic active surfaces and shows high photoelectric conversion efficiency. Thus, the O-Nb 2 O 5 nanosheets dominantly exposed (010) facet have potential applications in photocatalyst and photoelectric nanodevices .
研究领域:
材料科学
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光催化
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纳米材料
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无机化学
·
能源材料
✓ 已验证
DOI
高影响因子
MATERIALS CHARACTERIZATION
·
2024
·
IF 4.8
Wenya Li,Yongsheng Liu,Jingxin Li,Yejie Cao
(Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )B 2 -SiC ceramics with an open porosity of only 0.49 % were successfully fabricated in this work by the reactive melt infiltration (RMI) method. Air plasma flame ablation behavior of (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )B 2 -SiC ceramics under 2300 °C temperature exhibited excellent resistance with mass and linear ablation rates of 3.66 mg/s and 0.88 μm/s, respectively. During ablation, the transition from continuous melting sublimation of Si and oxidation of SiC to oxidation of (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )B 2 occurred. The uphill diffusion of Ti atoms transited (Ti,Zr,Hf,Nb,Ta)O x to Ti(Nb x Ta 1-x ) 2 O 7 while Zr 0.5 Hf 0.5 O 2 continuously precipitated. A multicomponent oxide layer of (Ti,Zr,Hf,Nb,Ta)O x along with (Zr,Hf) 6 Ta 2 O 17 , (Hf,Zr)(TiO 4 ) 2 , and (Zr,Hf) x (Ti,Ta) 1-x O embedded in SiO 2 melt was eventually formed on the ceramic surface. This oxide layer was spread above the high melting point Zr 0.5 Hf 0.5 O 2 , Ti(Nb x Ta 1-x ) 2 O, and low oxygen content (Ti,Zr,Hf,Nb,Ta)O x to form a stable, dense, and high viscosity protective layer.
研究领域:
材料科学
·
航空航天材料
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产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Lei Wang,Xudong Liu,Mu Zhang,Xiaoguo Bi,Zhixin Ma,Jinsheng Li,Jialin Chen,Xudong Sun
(Nb 0.5 Ga 0.5 ) x Ti 1−x O 2 (x = 0.05%,0.2%,0.5%,1%,5%) single crystals were prepared by Verneuil method. Even if the doping amount is 0.05%, the dielectric permittivity (ε′) is obviously higher than that of pure rutile TiO 2 (260), reaching more than 10 4 . As the doping amount x increase, the ε′ increases, and reaches the maximum value when x = 5%, but the dielectric loss increases correspondingly. The best dielectric performance (ε′=1.0 ×10 5 , tanδ=0.034 under 1 kHz) is obtained when the doping amount is 0.5%. Even at 10 6 Hz, the dielectric loss is only 0.019, much lower than the reported ceramic samples. This may be due to the fact crystalline materials can effectively reduce defects such as grain boundary, second phase, porosity and segregation. The dielectric spectra, impedance analysis, XPS and DC bias results show that the colossal permittivity (CP) properties could be attributed to EPDD polarization. With the increase of doping concentration (>1%), the hopping polarization occurs, resulting in a slight increase in dielectric loss. These results indicate that TiO 2 crystal materials with lower dielectric loss are good candidates for dielectric materials. Taking TiO 2 crystal as the research object, we can have a clearer understanding of the origin of TiO 2 dielectric properties and the influence of doping ion content, which is of great significance to the development of TiO 2 -based dielectric materials.
研究领域:
材料科学
·
介电材料
·
晶体生长
·
固体物理
✓ 已验证
DOI
高影响因子
Cell Reports Physical Science
·
2025
·
IF 7.3
Zhongzhe Wei,Xu Liu,Mingxuan Wang,Yao Lv,Songtao Huang,Jing Wang,Ming Jiang,Zhixiang Yang,Zihao Yao,Sheng Dai,Xiaonian Li,Jianguo Wang
The semi-hydrogenation of alkynes represents a paramount chemical transformation in the synthesis of fine chemicals and pharmaceuticals. However, the structural evolution of active sites during the reaction remains elusive. Here, we constructed a self-adaptive Pd/Nb 2 O 5 catalyst for efficient semi-hydrogenation of alkynes. Mechanistic studies disclose that Pd/Nb 2 O 5 intelligently modulates its structure in response to the specific alkyne type, efficiently preventing Pd poisoning by weakening the strong adsorption of alkynes. During the hydrogenation of aliphatic alkynes, the Pd/Nb 2 O 5 interface undergoes dynamic changes, generating oxygen vacancies (O v ) in situ through hydrogen spillover. In contrast, for the case of reactants of aromatic alkynes, the interface sites remain relatively stable. Coverage-dependent kinetics reveal that the dynamic O v formation of Pd/Nb 2 O 5 is determined by the distinct adsorption mechanism of aromatic and aliphatic alkynes. Due to the evolving interface, Pd/Nb 2 O 5 exhibits a high turnover frequency value of 55,338 h −1 , breaking the linear scaling relationships.
研究领域:
催化
·
化学反应工程
·
材料科学
·
有机合成
✓ 已验证
产品关联
DOI
高影响因子
Crystals
·
2024
·Vol. 14
·期 5
·419
·
IF 2.4
Yifei Wang,Xiaoyang Chen
The demands of low-Curie-temperature (~−10 °C) positive temperature coefficient (PTC) thermistors are increasing in advanced precision integrated circuits and other industries. In this paper, the Nb-doped Ba0.55Sr0.45TiO3(BST)-based PTC resistivity materials are reported. The effects of the sintering process, especially the cooling rate on the PTC properties of the material, are investigated. The results indicate that the Ba0.55Sr0.45Ti0.9985Nb0.0015O3composition of the prepared PTC ceramics demonstrates promising PTC characteristics. These include a Curie temperature as low as −13 °C, a high temperature coefficient of 0.296 at −3.4 °C, a large enough resistivity change of 3.1 over a narrow phase transition temperature range of approximately 38 °C, and moderate resistivity below the Curie temperature. Such properties suggest that the Ba0.55Sr0.45Ti0.9985Nb0.0015O3ceramics are likely suitable for use in thermal management systems designed for low-temperature control.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Nano
·
2026
·
IF 16
Huafeng Fu,Shiteng Long,Jia Hu,Jiehua Li,Hansong Xue,Yu’an Chen,Fusheng Pan
To address the challenges of high hydrogen release temperatures, sluggish kinetics, and inadequate cycling performance of magnesium hydride (MgH2), we developed the niobium-based bimetallic compound catalyst CuNb2O6 with excellent catalytic performance. It was found that the MgH2/CuNb2O6 composite material achieved 4.28 wt % hydrogen uptake within 10 min at 100 °C, and even at a lower temperature of 50 °C, it has 2 wt % hydrogen absorption capacity within 60 min, showing excellent hydrogen absorption performance. For hydrogen desorption, the MgH2/CuNb2O6 composite material demonstrated exceptional midtemperature hydrogen release kinetics, with 4.65 wt % hydrogen released within 20 min at 225 °C. The apparent activation energy for hydrogen release of MgH2/CuNb2O6 was determined to be 50.95 kJ/mol, which was approximately 66.4% less than that of ball-milled magnesium hydride. Cyclic testing further confirmed the stability of the MgH2/CuNb2O6 composite, with its hydrogen storage capacity stabilizing at 5.21 wt % after 50 cycles. Catalytic mechanism studies revealed that the MgH2/CuNb2O6 composite undergoes in situ reconstruction of multiple-phase catalytically active species, which effectively improved the hydrogen storage performance of MgH2. This work innovatively constructed a representative Mg2Cu@NbO2 heterojunction, and the results showed that hydrogen molecules were significantly activated at the interface, demonstrating the synergistic catalytic effect between the Cu and Nb species. This study provides a possible approach for designing high-efficiency catalysts for magnesium-based hydrogen storage materials.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF LUMINESCENCE
·
2019
·
IF 2.961
Su Zhang,Lingling Lv,Hongjie Wang,Chongyang Zhu,Ran Pang,Jing Feng,Da Li,Guanyu Liu,Lihong Jiang,Chengyu Li
The 0.8CaWO 4 -0.2EuMO 4 (M = Nb, Ta) solid solution and Eu 3+ , Ta 5+ and Nb 5+ single doped CaWO 4 were prepared by a high-temperature solid state reaction technique. Experiments show that the addition of Nb 5+ and Ta 5+ can increase the red luminescence of Eu 3+ in CaWO 4 . In this paper, the composition and structure of solid solution were analyzed by X ray diffraction (XRD), Fourier transform infrared spectrum and Raman spectrum analysis. The luminescence properties of the solid solution were studied by means of stable photoluminescent spectra, diffuse reflectance spectra (DRS), fluorescent decay curves and variable temperature spectra. By combining structural analysis, J-O theoretical calculation and experimental results, we believe that the significant improvement of the emission efficiency comes from the decrease of non-radiation relaxation rate.
研究领域:
材料科学
·
光学
✓ 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）