Advanced Science
·
2023
·Vol. 10
·期 28
·2302882
·
IF 15.1
Yanan Huang,Jibing Shen,Shuai Lin,Wenhai Song,Xuebin Zhu,Yuping Sun
High-quality few-layer M 4 C 3 T x (M = V, Nb, Ta) MXenes are very important for applications and are necessary for clarifying their physicochemical properties. However, the difficulty in etching for themselves and the existence of MC/MC 1−δ and M-Al alloy impurities in their M 4 AlC 3 precursors seriously hinder the achievement of defect-free few-layer M 4 C 3 T x (M = V, Nb, Ta) MXenes nanosheets. Herein, three different defect-free few-layer M 4 C 3 T x (M = V, Nb, Ta) nanosheets are obtained by using a universal synthesis strategy of calcination, selective etching, intercalation, and exfoliation. Comprehensive characterizations confirm their defect-free few-layer structure feature, large interlayer spacing (1.702–1.955 nm), types of functional groups (–OH, –F, –O), and abundant valance states (M 5+ , M 4+ , M 3+ , M 2+ , M 0 ). M 4 C 3 T x (M = V, Nb, Ta) free-standing films obtained by vacuum filtration of few-layer M 4 C 3 T x inks show good hydrophilia, high thermostability, and conductivity. A roadmap on synthesis of defect-free few-layer M 4 C 3 T x (M = V, Nb, Ta) nanosheets are proposed and three key points are summarized. This work provides detailed guidelines for the synthesis of other defect-free few-layer MXenes nanosheets, but also will stimulate extensive functional explorations for M 4 C 3 T x (M = V, Nb, Ta) MXenes nanosheets in the future.
研究领域:
材料科学
·
化学
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DOI
高影响因子
Journal of Superconductivity and Novel Magnetism
·
2023
·Vol. 36
·期 7
·1737-1750
·
IF 1.8
Shan Shuo,Li Jie,Li Pengwei,Wang Yonglun,Pi Siwen,Zhao Xuan
BaFe 12− x Nb x O 19 ( x = 0.00, 0.04, 0.08, 0.12, 0.16, and 0.20) with a nominal composition for M-type hexagonal barium ferrite was prepared using solid-state sintering methods. The microstructure and magnetic properties of hexaferrite were characterized using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, field-emission scanning electron microscopy (FESEM), and vibrating-sample magnetometry (VSM). XRD results revealed that the crystal structure of barium ferrite remained intact after Nb doping, maintaining a single barium ferrite phase. FESEM confirmed the hexagonal crystal structure of the sample. Energy-dispersive X-ray spectroscopy showed increased Nb content and decreased Fe content without the formation of other elements. FTIR revealed bands at 598 and 445 cm −1 corresponding to tetrahedral and octahedral clusters, respectively. The VSM test showed that the saturation magnetization ( M s ), residual magnetization ( M r ), and coercivity ( H c ) initially increased and then decreased with increasing Nb doping, reaching maximum values of 92.297 emu/g, 44.256 emu/g, and 3367.53 Oe, respectively, at x = 0.08.
研究领域:
材料科学
·
磁学
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DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2026
·
IF 5.1
Liu Chen,Yutong Guo,Rantao Dong,Wenjing Song,Ling Huang,Weiping Fang,Weikun Lai
The competitive adsorption and activation of H 2 and NH 3 molecules presents a fundamental challenge in catalytic reductive amination for sustainable amine synthesis. In this study, we address this issue by constructing a Ni/NbW 0.3 catalyst featuring a W-O-Nb composite oxide support designed to selectively enhance NH 3 adsorption and activation. Comprehensive characterization confirms that W doping creates a unique NbW x O (5/2+3x) structure with abundant W-O-Nb bridges, which generates strong Brønsted acid sites. These sites significantly enhance NH 3 protonation, thereby selectively promoting the rate-determining hydroammonolysis step by enhancing nucleophilic addition on the Schiff base intermediate. Hence, the Ni/NbW 0.3 catalyst delivers 99.9% yield of furfurylamine from the reductive amination of furfural, with a formation rate of 0.025 mol·g⁻ 1 ·h⁻ 1 under mild conditions (60 °C, 3 MPa H 2 , 0.4 MPa NH 3 ). Kinetic analyses reveal that the W-O-Nb structure substantially reduces both the activation energy (26.9 kJ·mol⁻ 1 ) and NH 3 reaction order (0.58), while poisoning experiments verify the essential role of Brønsted acid sites. The catalyst also demonstrates broad substrate adaptability and excellent recyclability. This work provides fundamental insights into the relationship between acid site engineering and reductive amination kinetics, establishing the W-O-Nb heterostructure design as an effective strategy for developing advanced amination catalysts.
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高影响因子
MICROCHIMICA ACTA
·
2021
·Vol. 188
·期 2
·1-11
·
IF 5.833
Liu Bin,Wang Baichun,Yan Yinghua,Tang Keqi,Ding Chuan-Fan
A strategy for effectively enriching global phosphopeptides was successfully developed by using ammonia methyl phosphate (APA) as a novel chelating ligand and Ti 4+ and Nb 5+ as double functional ions (referred to as Fe 3 O 4 @mSiO 2 @APA@Ti 4+ /Nb 5+ ). With the advantage of large specific surface area (151.1 m 2 /g), preeminent immobilized ability for metal ions (about 8% of total atoms), and unbiased enrichment towards phosphopeptides, Fe 3 O 4 @mSiO 2 @APA@Ti 4+ /Nb 5+ displays high selectivity (maximum mass ratio β-casein to BSA is 1:1500), low limit of detection (LOD, as low as 0.05 fmol), good relative standard deviation (RSD, lower than 7%), recovery rate of 87% ( 18 O isotope labeling method), outstanding phosphopeptide loading capacity (330 μg/mg), and at least five times re-use abilities. In the examination of the actual sample, 24 phosphopeptides were successfully detected in saliva and 4 phosphopeptides were also selectively extracted from human serum. All experiments have shown that Fe 3 O 4 @mSiO 2 @APA@Ti 4+ /Nb 5+ exhibits exciting potential in view of the challenge of low abundance of phosphopeptides.
Graphical abstract
研究领域:
生物化学
·
蛋白质组学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2017
·
IF 2.986
Shao-Feng Duan,Zhi-Hao Zhao,Rui-Fang Ge,Xin-Yu Kang,Yu-Kai Lv,Hongqiang Wang,Yejing Dai
0.8Bi 0.5 Na 0.5 Ti (1- x ) Nb x O 3 −0.2Sr 0.85 Bi 0.1 TiO 3 (BNT-SBT- x Nb, x = 0.00, 0.01, 0.02, and 0.03) piezoelectric ceramics were prepared by traditional solid state reaction and the influence of Nb substitution on the phase structure, ferroelectric , piezoelectric, and electric-field-induced strain properties in BNT-SBT ceramics were studied. XRD results exhibited that Nb 5+ ions could fully diffuse into BNT-SBT structure to form a solid solution when x = 0.01. P-E loops and S-E curves suggested that the ferroelectric phase transformed to ergodic relaxor state (FE-to-ER) with the increasing the amount of Nb additive, indicating the ferroelectric long-ranged order was disturbed by the excess of Nb. With increasing Nb doping, phase transition temperature from normal ferroelectric to ergodic relaxor (short for T F-R ) could be reduced from 120 °C to 40 °C. Furthermore, for sample with x = 0.01, the normalized strain d 33 * got a maximum value ~571 pm/V due to the phase transition from ergodic relaxor to ferroelectric (ER-to-FE) under electric field.
研究领域:
材料科学
·
物理学
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产品关联
DOI
高影响因子
Small Structures
·
2022
·Vol. 4
·期 1
·2200161
·
IF 11.343
Lu Chen,Youbing Li,Ke Chen,Xiaojing Bai,Mian Li,Shiyu Du,Zhifang Chai,Qing Huang
Entropy stabilization is an effective method to design and explore MAX phases with outstanding properties via tuning constituent elements and crystal structures, which have received considerable critical attention. Currently, some medium-/high-entropy (ME/HE) MAX phases, whose A layers are composed of Al, S, and magnetic elements, are reported, while few discussions about ME/HE-MAX phases with other A elements (e.g., Sn) are conducted. Herein, fully dense ME/HE-MAX phase bulks ((TiVNb) 2 SnC, (TiVNbZr) 2 SnC, and (TiVNbZrHf) 2 SnC) are designed and synthesized because of the chemical diversity of MAX phases. The results of Rietveld refinement of X-ray diffraction, scanning electron microscopy, and high-resolution scanning transmission electron microscopy-affiliated energy-dispersive spectrometer analysis comprehensively verify the crystal structure of ME/HE-MAX phases. Both the electrical conductivity and the charge carrier mobility are significantly lower than the reported correlation ternary MAX phases, due to the electron scattering and structural defects in ME/HE-MAX phase crystal structures. Similarly, the electron contribution of thermal conductivity is gradually declining; on the contrary, the phonon plays an increasingly dominant role as temperature increases. Owing to the richness in composition of MAX phases, herein, a composition design route for discovering new MAX phases and tuning their properties is indicated.
研究领域:
材料科学
·
凝聚态物理
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Zhangyi Huang,Zhengwei Zhu,Mingyu Su,Yang Shi,Mao Deng,Ruichong Chen,Zhijun Wang,Zhi Zhou,Jianqi Qi,Haomin Wang
This study investigated the high-temperature oxidation behaviors of TMC ceramics. The results indicate that the high-temperature oxidation curves of the four TMC ceramics follow a parabolic law, suggesting a diffusion-controlled process. The activation energies for the oxidation of TaC, NbC, TiC, and ZrC ceramics are 105.4, 124.3, 169.3, and 78.7 kJ/mol, respectively, with oxidation rate constants at 1000 °C of 16.84, 40.45, 0.18, and 14.43 mg 2 /cm 4 ·h for each ceramic, respectively. The temperatures at which the ceramics disintegrate into fragments in high-temperature air are 800, 800, >1000, and 600 °C, respectively. The anti-oxidation performance of the four TMC ceramics ranks as follows: TiC > TaC > NbC > ZrC. In comparison to the reported high-entropy carbide ceramics, the TiC ceramic in this study demonstrates superior anti-oxidation performance due to dense TiO 2 layer formation, characterized by significantly low oxidation rates and excellent structural stability.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Results in Surfaces and Interfaces
·
2025
·
IF 4.4
Xin Liu,Jinshan Zhang,Xin Wang,Xu Zheng,Yong Du,Meichen Pan,Chen Liu,Hisahiro Einaga,Hajime Hojo,Pengwei Huo
With the increasingly stringent requirements for the treatment of industrial nitrogen oxides (NO x ), ammonia selective catalytic reduction (NH 3 -SCR) has emerged as the most widely adopted denitrification technology in industrial settings. A series of CeNbO x nano-catalyst with varying Nb compositions were synthesized via the solvothermal method for NH 3 -SCR. All the CeNbO x samples presented considerable NO x conversion, exceeding 80% within a broad temperature window of 200-350°C. In addition, the optimal sample shown high stability and strong resistance to SO 2 /H 2 O at 225°C. The influence of Nb element on structural properties of the CeNbO x samples was investigated and elucidated using multiple characterization techniques. The NH 3 -SCR process was further studied by in situ infrared Fourier transform spectroscopy ( in situ FTIR ), temperature-programmed reduction with H 2 (H 2 -TPR) and X-ray photoelectron spectroscopy (XPS), which revealed that the improved NO x conversion can be attributed to the role of Nb in suppressing the crystal growth of CeO 2 , promoting the adsorption of oxygen species, increasing the distribution of Ce and improving the redox ability.
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DOI
高影响因子
Scientific Reports
·
2017
·Vol. 7
·期 1
·1-9
·
IF 4.259
Ke Shanming,Li Tao,Ye Mao,Lin Peng,Yuan Wenxiang,Zeng Xierong,Chen Lang,Huang Haitao
(In + Nb) co-doped TiO 2 (TINO) rutile is an emerging material with a colossal dielectric permittivity (CP) and a low dielectric loss over wide temperature and frequency ranges. The electrical inhomogeneous nature of TINO ceramics is demonstrated by direct local current probing with high-resolution conductive atomic force microscopy (cAFM). The CP response in TINO is found to originate from the electron-pinned defect dipole induced conductive cluster effect and the electrode effect. Two types of dielectric relaxations are simultaneously observed due to these two effects. With the given synthesis condition, we found TINO shows a highly leaky feature that impairs its application as a dielectric material. However, the fast-temperature-rising phenomenon found in this work may open a new door for TINO to be applied as a potential electrothermal material with high efficiency, oxidation-proof, high temperature stability, and energy saving.
研究领域:
材料科学
·
电介质物理
✓ 已验证
DOI
PubMed
高影响因子
RSC Advances
·
2022
·Vol. 12
·期 34
·22070-22081
·
IF 4.036
Xin Fu,Ruisong Li,Yucang Zhang
This study explores an aerosol-assisted method to prepare an efficient support for the Pt catalyst of polymer electrolyte membrane fuel cells (PEMFCs). Titania nanoparticles and mesoporous niobium-doped titania nanoparticles were prepared by aerosol-assisted self-assembly using titanium(IV) isopropoxide and niobium(V) ethoxide as the titanium and niobium sources for application as non-carbon supports for the platinum electrocatalyst. The structural characteristics and electrochemical properties of the supports were investigated by transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, electron paramagnetic resonance, inductively coupled plasma optical emission spectrometry, and dynamic light scattering. The Brunauer–Emmett–Teller method was used to calculate the specific surface areas of the samples, and the pore size distribution was also examined. The results demonstrated that under a radial concentration gradient, the aerosol droplets self-assembled into a spherical shape, and mesoporous supports were obtained after subsequent removal of the surfactant cetyltrimethylammonium bromide by annealing and washing. The hydrothermal technique was then used to deposit platinum on the TiO2-based supports. The electrical conductivity of the non-carbon support was enhanced by the strong metal–support interaction effect between the platinum catalyst particles and the porous niobium-doped TiO2 support. The half-wave potential, electrochemical surface area, mass activity, and specific activity of the obtained Pt/Nb-TiO2 catalyst all surpassed those of commercial Pt/C.
研究领域:
材料科学
·
电化学
·
催化
·
纳米技术
·
能源材料
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2026
·
IF 6.7
Qiannan Huang,Pengping Li,Yu Wei,Xinxing Zhang,Mingfeng Zhong,Pingan Liu,Hui Wang,Zhijie Zhang
Multilayer piezoelectric ceramics employing base metals such as copper as inner electrodes are ideal for components like micro-displacement actuators and ultrasonic motors, which require materials possessing high piezoelectric performance, high Curie temperature, and low sintering temperature. In this study, by introducing a ternary composite additive of Li₂CO₃-CuO-Nb₂O₅ into the 0.075Pb(Mn 1/3 Sb 2/3 )O 3 -0.925Pb(Zr 0.48 Ti 0.52 )O 3 (PMS-PZT) system, PMS–PZT ceramics with excellent overall properties were successfully fabricated at a sintering temperature of 950 °C, exhibiting d 33 = 361.2 pC/N, Tc= 339.8 ℃, tanδ= 0.6%, Q m = 668.8, k p = 0.65. The effects of sintering temperature on the structure and properties of the ceramics were systematically investigated. The synergistic action of Li 2 CO 3 and CuO effectively reduced the sintering temperature and facilitated the incorporation of Nb into the B-site at relatively low temperatures, thereby significantly enhancing the piezoelectric performance and Curie temperature of the material. This work not only provides an effective low‑temperature sintering approach for the PMS–PZT ceramic system, but also offers important references for the selection of material systems and additives in the development of multilayer piezoelectric devices.
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DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2026
·
IF 3.1
Haihua Wang,Haonan Wang,Kewei Shu,Chaoxian Chen,Qing Liu,Rui Cao,Jiaheng Li,Xing Yang,Zhuyu Li
Owing to its high lithium-ion conductivity, the cubic garnet-phase material Li 7 La 3 Zr 2 O 12 (LLZO) is a widely adopted key component in the fabrication of composite solid-state electrolytes (CSSEs). Nevertheless, the advancement of all-solid-state lithium batteries (ASSLBs) is still hindered by two major challenges: the high intrinsic crystallinity of poly(ethylene oxide) (PEO) and poor interfacial stability. Herein, cubic garnet Li 6.3 La 2.7 Ba 0.3 ZrNbO 12 (LLBZNO) featuring Ba and Nb co-doping was first prepared by a conventional solid-state method. Following this, the material was dispersed within a PEO matrix to construct composite solid-state electrolytes. Adding LLBZNO served to decrease PEO's crystallinity while enhancing its mechanical flexibility and bolstering its interfacial compatibility with lithium metal. The optimized membrane demonstrated superior properties, including a high Li + transference number of 0.75 (at 60°C) and an extended electrochemical stability window of up to 5.1 V (vs. Li/Li + ) under the present testing conditions. It also showed an excellent ability to suppress dendrites, facilitating stable cycling at 0.1 mA cm −2 for 1500 h without short-circuiting. Furthermore, the LFP/LLBZNO–PEO/Li battery delivered a high discharge capacity of 101.6 mA h g −1 after 300 cycles at 1°C with nearly 99% coulombic efficiency. These findings highlight that LLBZNO-PEO composite solid electrolytes possess superior ionic transport, electrochemical stability, and mechanical robustness, providing a viable pathway toward the advancement of next-generation high-performance ASSLBs.
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DOI
高影响因子
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