Nature Communications
·
2024
·Vol. 15
·期 1
·1-12
·
IF 14.7
Deng Xianyu,Zhang Jianjun,Qi Kezhen,Liang Guijie,Xu Feiyan,Yu Jiaguo
Constructing S-scheme heterojunctions proves proficient in achieving the spatial separation of potent photogenerated charge carriers for their participation in photoreactions. Nonetheless, the restricted contact areas between two phases within S-scheme heterostructures lead to inefficient interfacial charge transport, resulting in low photocatalytic efficiency from a kinetic perspective. Here, In 2 O 3 /Nb 2 O 5 S-scheme heterojunctions are fabricated through a straightforward one-step electrospinning technique, enabling intimate contact between the two phases and thereby fostering ultrafast interfacial electron transfer (<10 ps), as analyzed via femtosecond transient absorption spectroscopy. As a result, powerful photo-electrons and holes accumulate in the Nb 2 O 5 conduction band and In 2 O 3 valence band, respectively, exhibiting extended long lifetimes and facilitating their involvement in subsequent photoreactions. Combined with the efficient chemisorption and activation of stable CO 2 on the Nb 2 O 5 , the resulting In 2 O 3 /Nb 2 O 5 hybrid nanofibers demonstrate improved photocatalytic performance for CO 2 conversion.
研究领域:
材料科学
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光催化
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纳米技术
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Wenqian Zhang,Li Xiao,Jiangfeng Zheng,Yuelian Zhong,Bo Shi,Han Chen,Haikuo Fu
The electrochemical properties and thermal stability of the LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622) material have been significantly improved by Nb 2 O 5 nanocoating. The electrochemical properties were researched systematically by various electrochemical tests, and the molar ratio of Nb 2 O 5 to NCM622 was evaluated as 0.5 mol%. Results showed that Nb 2 O 5 nanocoated sample exhibited good cyclic performance, whose capacity retention was 92.36%, whereas that of the bare NCM was only 87.59% after 200 cycles under 1C at 25 °C. In addition, the Nb 2 O 5 surface-coated sample exhibited a good discharge capacity of 164.05 mAh g −1 after 200 cycles under 1C at 60 °C. The result owing to the nano coating of Nb 2 O 5 , which greatly increased the thermal stability, thereby maintaining remarkable specific capacity even in high-temperature environments. The modified sample could maintain a relatively complete structure after cycling, whereas the bare sample had already collapsed. Based on the transmission electron microscopic images, the thickness of the coating layer was about 15 nm. The nanocoating of Nb 2 O 5 was prepared by solid-phase reaction. This method is simple and convenient, which is conducive to industrial production and commercialisation promotion. The Nb 2 O 5 surface coating can enhance the electrochemical properties of the cathode materials , as well as strengthen the thermal and structural stability, which can extend the battery life.
研究领域:
材料科学
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电化学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Yuda Lin,Shenghui Zheng,Yiheng Chen,Liting Qiu
Monoclinic Nb 2 O 5 (H–Nb 2 O 5 ) as an prospect anode material for lithium ion batteries due to its high theoretical specific capacity of 250 mAh g -1 and a safe working voltage in the range of 1–3 V, but the inherent low electron conductance greatly limits its high-rate performance. In this paper, we synthesized F-doped Nb 2 O 5 with S/F co-doped carbon composites (F–Nb 2 O 5 @SFC) by simple high-temperature annealing method, XPS and EPR analysis results show that the composites has abundant of oxygen vacancies. Under the dual effects of F − doping and oxygen vacancy, the free electron concentration of Nb 2 O 5 structure is greatly increased, and the conductive network provided by SFC accelerates the electron transport process, thus, the obtained F–Nb 2 O 5 @SFC material achieves excellent conductivity. In addition, the charge density difference results indicate that the unbalanced charge distribution around oxygen vacancies provides additional Li + active sites, and the constructed electric field accelerates the transmission of Li + . The fast Li + /electron transfer kinetics of the F–Nb 2 O 5 @SFC electrode has achieved excellent storage performance, with a reversible specific capacity of 165 mAh g -1 at 1A g -1 after 600 cycles and a high-rate capacity of 130 mAh g -1 at 10A g -1 .
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Nano Materials
·
2018
·
IF 0
Deli Shen,Weifeng Zhang,Yafeng Li,Antonio Abate,Mingdeng Wei
In a typical high-performance perovskite solar cell (PSC), the electron-transporting layer (ETL) plays a critical role in facilitating the transportation of the photogenerated carriers from perovskite to electrode. In the present work, the solution-processed Nb2O5 film is successfully prepared to serve as an alternative for replacing the overwhelmingly dominated TiO2 ETL with a facile deposition approach. By adjusting the spin-coating process of the precursor solution, the best power conversion efficiency of 19.2% is achieved in the Nb2O5-based planar PSC when the thickness of C–Nb2O5 ETL is about 100 nm. The characterization including ultraviolet photoelectron spectroscopy, electronic impedance spectroscopy, and photoluminescence spectrum results elucidate that the impressive photovoltaic performances can be attributed to the proper Nb2O5 ETL conductive band, the lower charge recombination rate, the more efficient extraction, and transportation of the photogenerated carriers from the perovskite absorber.
研究领域:
材料科学
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能源科学
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光伏技术
✓ 已验证
产品关联
DOI
ACS Applied Materials & Interfaces
·
2022
·
IF 10.383
Piaoyun Yang,Yijing Fan,Keyang Hu,Lei Jiang,Lun Tan,Zhao Wang,Ang Li,Shulin Yang,Yongming Hu,Haoshuang Gu
The research and development of low-power-consumption and room-temperature hydrogen sensors are of great significance for the safe application of hydrogen energy. Herein, orthorhombic Nb2O5–x nanobelts are prepared through a combined procedure of hydrothermal, ion exchange, and annealing treatment in Ar. The topological transformation process results in the formation of abundant surface defects including chemical defects such as Nb4+, oxygen vacancies, and disordered microregions, which lead to the abnormal p-type conducting and hydrogen sensing behavior. Moreover, the orthorhombic Nb2O5–x nanobelts exhibit fast and sensitive room-temperature hydrogen sensing performance, which shows greater advancement than the monoclinic, tetragonal, and hexagonal Nb2O5 one-dimensional (1D) nanostructures. The response time and lowest limit of detection of the as-fabricated room-temperature sensor decrease to 28 s and 3.5 ppm, respectively. The sensor also exhibits a highly selective hydrogen response against CO, CH4, ethanol, H2S, and NH3. The hydrogen response of the Nb2O5–x nanobelts can be attributed to the redox reaction between hydrogen and preadsorbed oxygens. The defective surface structure and the prolonged dimension of the nanobelts give rise to the highly reactive surface and the suppression of the negative nanojunction effect, which greatly improves the sensing performance. The orthorhombic lattice structure can also promote gas adsorption and diffusion behavior due to its specific catalytic and pathway effect. The results of this work can be helpful for the rational design and defect engineering of the Nb2O5-based 1D nanostructures for room-temperature hydrogen sensing applications.
研究领域:
材料科学
·
传感器技术
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2021
·Vol. 96
·期 6
·1553-1560
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IF 3.174
Sibo Li,Jiaxun Zhang,Hualiang An,Guirong Wang,Xinqiang Zhao,Yanji Wang
BACKGROUND The reaction integration of butanal self-condensation and successive hydrogenation (that is, one-step synthesis of 2-ethylhexanol from butanal) is an efficiency way to simply process flow and reduce energy consumption for the commercial manufacture of 2-ethylhexanol (2EHO). In the present work, a NiO-MnO 2 /Nb 2 O 5 -TiO 2 catalyst was prepared for the integration reaction to reach a high 2-ethylhexanol selectivity. Furthermore, the reaction integration was investigated kinetically for the next scale-up. RESULTS A 2EHO selectivity of 90.0% was achieved at a complete conversion of butanal with the help of reduction-in-reaction technique in this reaction integration. The reaction rate of butanal is determined by the reversible aldol self-condensation reaction and its direct hydrogenation reaction. The reaction order with respect to butanal in the two reactions is, respectively, 2.004 and 1.004. The activation energy of the hydrogenation reaction is higher than that of the forward reaction of the self-condensation, suggesting the suppressive effect the reaction integration on the direct hydrogenation. CONCLUSION The reaction integration promotes butanal self-condensation and successive hydrogenation and it suppresses butanal direct hydrogenation by using NiO-MnO 2 /Nb 2 O 5 -TiO 2 catalyst with the help of reduction-in-reaction technique, giving rise to a pretty high selectivity of 2-ethylhexanol. The establishment of the integration reaction kinetics will lay the foundation for reactor design and analysis. © 2021 Society of Chemical Industry
研究领域:
化学工程
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催化化学
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反应动力学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
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2022
·
IF 9.794
Di Wang,Zihan Zhang,Daxu Zhang,Zhicheng Zheng,Gen Chen,Ning Zhang,Xiaohe Liu,Renzhi Ma
Nb 2 O 5 has attracted great attention as a promising anode material for lithium-ion batteries (LIBs) due to relatively high rate-capacity, fast charge/discharge ability and excellent cycling performance. Unfortunately, the poor electron conductivity restricts its application. In this work, we report an effective method to synthesize large-size Nb 2 O 5 nanosheets wrapped within carbon layer (denoted as Nb 2 O 5 @C) by using layered K 4 Nb 6 O 17 (abbreviated as KN) as the templates of dopamine polymerization, followed by the carbonization . It is demonstrated that dopamine not only serves as the carbon source, but also promotes the phase transition and the morphology transition. The obtained Nb 2 O 5 @C nanosheets with enhanced electron conductivity deliver outstanding rate capability (485, 372, 304, 267 and 232 mAh g −1 at the current density of 0.1, 0.2, 0.5, 1 and 2 A g −1 , respectively) with a low capacity fading-rate of about 0.02% after 1000 cycles at 2 A g −1 . This work may provide a helpful strategy in developing the high-rate lithium-ion storage applications for other related materials.
研究领域:
材料科学
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电化学
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纳米技术
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能量存储
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Xuxu Wang,Ying Bai,Ruxiu He,Fen Yao,Limin Chang,Ping Nie
Metastable orthorhombic niobium pentoxide (T-Nb 2 O 5 ) with fast lithium storage capability and safe operating voltage is recognized as suitable anode material for high power density lithium-ion batteries (LIBs). While, the T-Nb 2 O 5 also suffers from low electrical conductivity in practical applications. In this work, the electrochemical performance of T-Nb 2 O 5 is enhanced by constructing a free-standing electrode and introducing the N-doped carbon substrate. The free-standing electrode consisting of the network-structured Nb 2 O 5 layer and porous carbon cloth (PCC) avoids the use of binders and benefits the electron transport. In addition, the introduction of N-doped carbon substrate is also beneficial to enhance the electronic conductivity of the Nb 2 O 5 . When used as the anode for LIBs , the PCC@Nb 2 O 5 demonstrates excellent long cycle life and rate performance, with a specific capacity of over 150 mA h g −1 after 3200 cycles at a current density of 1000 mA g −1 . This strategy of constructing free-standing electrodes provides new options for obtaining high-performance Nb 2 O 5 anode electrodes.
研究领域:
材料科学
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电化学
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能源存储
✓ 已验证
产品关联
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2019
·Vol. 7
·期 2
·437-446
·
IF 5.934
Yuwei Wang,Xianggui Kong,Meihong Jiang,Fazhi Zhang,Xiaodong Lei
A bifunctional ZnIn2S4/Nb2O5 (ZIS/NbO) photocatalyst was constructed by growing Nb2O5 nanospheres on the petals of ZnIn2S4 microspheres via a facile hydrothermal approach. The composite possessed a direct Z-scheme heterostructure that was confirmed by in situ irradiated X-ray photoelectron spectroscopy (ISI-XPS) and electron spin resonance (ESR) measurements. Owing to the good charge separation efficiency in the Z-scheme system, the lifetime of charge carriers in ZIS/NbO was obviously prolonged. Thus, the rate of hydrogen evolution for optimized ZIS/NbO was 2.8 and 1.8 times higher than that of Nb2O5 and ZnIn2S4, respectively. Furthermore, the ZIS/NbO also showed good performance for the oxidation of biomass-derived intermediate 5-hydroxymethylfurfural (HMF) to value-added products. More importantly, the coupled photocatalytic H2 reduction and HMF oxidation were achieved on the ZIS/NbO Z-scheme heterostructure at the same time. Due to the presence of a direct Z-scheme heterojunction that prevents the recombination of photogenerated electrons and holes in the composite, the ZIS/NbO displayed excellent photocatalytic performance. Our findings are expected to offer a broad optical window for fabricating bifunctional heterostructured composites for coupled photocatalytic reduction and oxidation.
研究领域:
材料科学
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环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Xiaohui Wu,Yulan Jing,Yuanxun Li,Hua Su
The comprehensive properties and sintering temperature of microwave dielectric ceramics are the key factors limiting their practical application. In this work, a novel strategy of complex (Co 1/3 Nb 2/3 ) 4+ ions substituted and adding glass (Li 2 O-B 2 O 3 - SiO 2 -CaO-Al 2 O 3 : LBSCA) was proposed to greatly enhance the microwave dielectric properties of Ba 3 Ti 4- x (Co 1/3 Nb 2/3 ) x Nb 4 O 21 (0 ≤ x ≤ 12 mol%, x CN-BTN) ceramics. A new ceramic of (Co 1/3 Nb 2/3 ) 4+ substitution improved hexagonal phase BTN was successfully fabricated and systematically investigated. As the increased of (Co 1/3 Nb 2/3 ) 4+ ions concentration, the Q× f was greatly increased because of higher packing fraction, and the reduction in the [Nb1/Ti1O 6 ] octahedral distortion caused great changes of τ f . Besides, the P-V-L theory revealed that the Ti/Nb ratio greatly contributed in permittivity ε r , and the Nb-O bonds mainly affected dielectric loss, especially in Nb(1)-O2(1) bond. As a result, the superior microwave dielectric properties were obtained in 6CN-BTN ceramic sintered at 950 °C: ε r ∼40.99 ± 0.48, Q× f ∼17,310 ± 565 GHz, and τ f ∼8.62 ± 4.34 ppm/°C. More encouragingly, 6CN-BTN showed good compatibility with silver, making it a promising K 40 LTCC material for filter and dielectric resonators . This study presented a new strategy to improve the properties of BTN-based materials by complex ions substitution, which was expected to provide a general approach for the design of advanced microwave dielectric ceramics for other material systems.
研究领域:
材料科学
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电子工程
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2025
·
IF 5.6
Longdi Ma,Yinxiang Han,Xiwen Chen,Yuran Chen,Liqiang Wang,Yangyang Fan,Xuemin Liang,Yapeng Kong
The molten salts electro-deoxidation process, also known as the FFC-Cambridge process, offers substantial potential for the environmentally friendly synthesis of niobium powder in a relatively short process. However, this process suffers from uncontrolled intermediate particle coarsening and the resultant sluggish oxygen-ion diffusion kinetics. To address this, we engineered a novel hierarchically porous Nb 2 O 5 (HPS-Nb 2 O 5 ) cathode with interconnected macropores (∼10 2 μm), mesopores (∼10 1 μm), and micropores (submicron). Electrochemical analyses coupled with potentiostatic electrolysis reveal a four-step reduction pathway of Nb 2 O 5 in molten Na 3 AlF 6 -K 3 AlF 6 -AlF 3 salts: Nb 2 O 5 →Na 2 Nb 8 O 21 /NbO 2 →NbO→Nb, where solid-state oxygen diffusion remains rate-limiting. The novel cathode pore architecture optimizes the solid-liquid interfaces between the cathode and the electrolyte, facilitating uniform insertion of Na⁺/F⁻ ions into cathode particles to generate intermediate particles. Consequently, rhombohedral Na 2 Nb 8 O 21 intermediate with uniform size and morphology was formed, thereby effectively preventing the excessive coarsening of intermediate particles and associated oxygen diffusion path elongation that occurs in the conventional electro-deoxidation processes. Remarkably, complete reduction of 1 g Nb 2 O 5 to Nb powder was achieved in only 1.5 h at 2.5 V. This represents an 8-13-fold efficiency enhancement over the reported processes. The resultant niobium powder exhibits uniform submicron particles (200–500 nm) with near-spherical morphology. This pore-structure-regulated strategy overcomes fundamental bottlenecks in the FFC process and offers broad applicability for the efficient preparation of diverse refractory metals and alloys.
研究领域:
材料科学
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电化学
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冶金学
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纳米技术
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Zhengyan Hao,Zhiwei Zhang,Xijia Yang,Xuesong Li,Yang Gao,Liying Wang,Yuxin Huang,Wei Lü
Zinc-ion hybrid supercapacitors (ZIHSCs) have garnered widespread attention due to their integration of the excellent characteristics of both batteries and capacitors. This study employs a synergistic strategy combining hydrothermal and high-temperature calcination methods to construct a nanosphere-structured T-Nb 2 O 5 composite anode material coated with reduced graphene oxide (rGO) on a flexible carbon cloth (CC) substrate (T-Nb 2 O 5 /rGO@CC), in conjunction with a hierarchical super-mesoporous activated carbon cathode (ACcp@CC) derived from discarded citrus peel. The rGO coating structure suppresses the volume expansion of the internal nanostructure caused by charging and discharging, effectively enhancing mechanical stability. At the same time, the three-dimensional conductive network of rGO effectively compensates for the poor intrinsic conductivity of Nb 2 O 5 . The constructed ZIHSC delivers a capacitance of 718.56 mF cm −2 at 1 mA cm −2 , and achieves a maximum energy density of 399.20 μWh cm −2 at 1 mW cm −2 . Furthermore, after 50,000 ultralong-cycle, the capacity retention rate is 104.17 %. The assembled flexible device not only possesses excellent mechanical properties but also delivers a specific capacitance of 389.89 mF cm −2 at 1 mA cm −2 , providing long-term power for various electronic devices. This study provides a solid theoretical reference for the design of stable composite structures and the investigation of ultra-long cycling performance in niobium-based electrode materials.
研究领域:
材料科学
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电化学
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储能技术
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纳米技术
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复合材料
✓ 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）