JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Fang Xu,Dainan Zhang,Gang Wang,Huaiwu Zhang,Yan Yang,Yulong Liao,Lichuan Jin,Yiheng Rao,Jie Li,Fei Xie,Gongwen Gan
NiCuZn ferrite ceramics with high permeability and low magnetic loss have great values in high frequency applications. Here, we synthesized uniform and compact NiCuZn ferrites with small grains (about 1.5 μm) at 875 ° C via adjusting additive amount of Nb 2 O 5 and Bi 2 O 3 . The influence of Bi 2 O 3 additives on the microstructure and magnetic properties of NiCuZn ferrite, especially for grain growth and grain size, have been investigated. SEM results indicated that Nb 2 O 5 can obviously suppress grain growth when a small amount of Bi 2 O 3 was added. Also, the liquid phase of Bi 2 O 3 only can promote movement of grain boundary and reduce porosities between grains. Thus, a NiCuZn ferrite with high permeability ( μ i ′ = 472.79), high saturation flux density ( B s = 0.313 T), high Q value (66.3) and low coercivity ( H c = 94.75 A/m) was obtained when 0.25 wt % Nb 2 O 5 -0.50 wt % Bi 2 O 3 was added. It is proved that improvement of compactness can enhance magnetic properties even though grain growth was suppressed. However, over much Bi 2 O 3 (more than 1.00 wt %) reduced the magnetic properties due to deterioration of grains uniformity and existence of non-magnetic Bi 2 O 3 liquid phase. Such a low temperature solid phase synthesis method (i.e., adding composite additive with different melting point oxide) should also facilitate preparation of other advanced ceramics for practical applications.
研究领域:
材料科学
·
磁学
✓ 已验证
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2019
·
IF 7.723
Yu Xin,Lin Dong,Yong Guo,Xiaohui Liu,Yongfeng Hu,Yanqin Wang
Production of aromatic hydrocarbons through lignin hydrodeoxygenation (HDO) is of significant importance. Previously, we found that Ru/Nb 2 O 5 was an excellent catalyst for the conversion of lignin to arenes with relatively high selectivity (71%). Herein, we aim to clarify which properties of Nb 2 O 5 influence the activity and selectivity. Four Ru/Nb 2 O 5 catalysts with different Nb 2 O 5 morphologies were used in the HDO of 4-methylphenol. Intensive studies show that layered Nb 2 O 5 supported Ru has more Nb O groups (unsaturated NbOx sites) and highest Ru dispersion, which led to the highest activity and toluene selectivity, this was further confirmed by loading pre-synthesized Ru colloids in various Nb 2 O 5 . Finally, a Ru/Nb 2 O 5 catalyst with more unsaturated Nb O groups was designed and it was found that even with enzymatic lignin as the feedstock, the selectivity to arenes can reach up to 94.8% with the yield of hydrocarbons of 99.6%. This study provides a promising strategy for catalyst design towards the selective production of aromatic hydrocarbons from lignin.
研究领域:
催化化学
·
可再生能源
✓ 已验证
DOI
高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2017
·Vol. 164
·期 4
·A820
·
IF 3.259
Junming Zhang,Hao Chen,Xiaowen Sun,Xiaojuan Kang,Yan Zhang,Chaohe Xu,Yuxin Zhang
Li-ion hybrid electrochemical capacitors (Li-HECs) with higher energy density than electric double layer capacitors (EDLC) and larger power density than current rechargeable batteries are attractive candidates in future energy related applications. However, the electrochemical properties of current Li-HECs are greatly restricted by its Li-ion insertion type of electrode materials. Herein, we report an efficient approach to prepare one dimensional T-Nb2O5 nanowires growth on activated carbon cloth as freestanding hybrid electrodes for Li-HECs. The T-Nb2O5 nanowires with diameter of 20∼50 nm and length of several micrometers cross with each other and form a three dimensional (3D) porous network. The designed hybrid electrodes can deliver a gravimetric capacitance as high as 220 mAh g−1 at current density of 0.5 C and advanced cycle life with capacity retention of 86% after 1000 cycles at 5 C. The outstanding electrochemical performances are mainly attributed to the reduction in the lithium ion diffusion length brought by the crossed porous structure. And the enhancement of electron transportation enjoys the benefit from the in-situ growth of T-Nb2O5 nanowires on carbon cloth and the binder-free electrode structure.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Rui Li,Xiangtao Huo,Xing Han,Zhipeng Wang,Mei Zhang,Min Guo
Reducing defect density and hindering charge recombination in perovskite film and at perovskite/semiconductor interface are crucial to perovskite solar cells (PSCs) performance. In this paper, hydrothermally prepared TiO 2 nanorod arrays (TNRAs) were coated with Nb 2 O 5 layer using a spin-coating method, and the modified TNRAs were used as scaffold for the deposition of perovskite films and corresponding PSCs in air environment. The effect of NbCl 5 concentration on the micro structure and photovoltaic properties of the formed perovskite films were investigated, and the enhancement mechanism was also elucidated. A champion efficiency of 16.50% (enhanced of 9.49% compared with the pristine one) was achieved when the concentration of NbCl 5 solution was 0.005 M. Such an enhanced performance of PSC might be mainly ascribed to two reasons: one was the improved perovskite film qualities including the enlarged average grain size, higher crystallinity and reduced defect density; the other was the formed energy barrier (Nb 2 O 5 ) between perovskite layer and TNRAs interface that hindered the charge recombination.
研究领域:
材料科学
·
能源技术
✓ 已验证
DOI
高影响因子
JOURNAL OF SOLID STATE ELECTROCHEMISTRY
·
2024
·
IF 2.6
Zhou Xiaozheng,Chen Anqi,Lu Chengwei,Ma Ruojian,Fang Ruyi,Gan Yongping,Wang Guoguang,Xu Jianping,Mao Qinzhong,Lu Xiaoxiao,Xia Xinhui,Xia Yang
LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) cathode material is prized in the electric vehicles (EVs) industry for its high capacity and voltage during operation. However, the high residual alkali content and inferior ionic conductivity of Ni‑rich cathode materials are the intractable obstacles to the large-scale commercial application for a long time. Herein, a feasible Nb 2 O 5 coating strategy is proposed to eliminate residual alkali along with constructing high Li + conductive coating layer on NCM811 cathode materials surface. Impressively, 0.3% Nb 2 O 5 ‑coated NCM811 cathode exhibits superior rate capability (146.4 mA h g −1 @400 mA g −1 ) and remarkable rate cyclic stability (188.5 mA h g −1 after 100 cycles with capacity retention of 94.8%). On the one hand, a small quantity of Nb 2 O 5 coating on NCM811 surface can react with surface residual alkali to promote the transformation of low electronic conductivity surface residual alkali into the Li + conductor of LiNbO 3 coating layer, enhancing Li + de-intercalation kinetics and rate performance. On the other hand, excessive Nb 2 O 5 coating may introduce Nb 5+ into the lattice of NCM811, acting as pivotal components within the Li + layer, which effectively suppresses the H2 ↔ H3 phase transition, contributing to long-term cyclic stability. This work paves a new path for the rational design and facile coating of Ni-rich oxide cathode materials with reinforced structure stability and boosted rate capability in high‑energy‑density lithium-ion batteries.
研究领域:
材料科学
·
电化学
·
能源存储与转换
✓ 已验证
DOI
高影响因子
ADVANCED MATERIALS
·
2018
·Vol. 30
·期 26
·1800963
·
IF 21.95
Xiangguo Wang,Qiucheng Li,Li Zhang,Zhongli Hu,Lianghao Yu,Tao Jiang,Chen Lu,Chenglin Yan,Jingyu Sun,Zhongfan Liu
Sodium-ion hybrid supercapacitors (Na-HSCs) by virtue of synergizing the merits of batteries and supercapacitors have attracted considerable attention for high-energy and high-power energy-storage applications. Orthorhombic Nb 2 O 5 ( T -Nb 2 O 5 ) has recently been recognized as a promising anode material for Na-HSCs due to its typical pseudocapacitive feature, but it suffers from intrinsically low electrical conductivity. Reasonably high electrochemical performance of T -Nb 2 O 5 -based electrodes could merely be gained to date when sufficient carbon content was introduced. In addition, flexible Na-HSC devices have scarcely been demonstrated by far. Herein, an in situ encapsulation strategy is devised to directly grow ultrathin graphene shells over T -Nb 2 O 5 nanowires (denoted as Gr-Nb 2 O 5 composites) by plasma-enhanced chemical vapor deposition, targeting a highly conductive anode material for Na-HSCs. The few-layered graphene capsules with ample topological defects would enable facile electron and Na + ion transport, guaranteeing rapid pseudocapacitive processes at the Nb 2 O 5 /electrolyte interface. The Na-HSC full-cell comprising a Gr-Nb 2 O 5 anode and an activated carbon cathode delivers high energy/power densities (112.9 Wh kg −1 /80.1 W kg −1 and 62.2 Wh kg −1 /5330 W kg −1 ), outperforming those of recently reported Na-HSC counterparts. Proof-of-concept Na-HSC devices with favorable mechanical robustness manifest stable electrochemical performances under different bending conditions and after various bending–release cycles.
研究领域:
材料科学
·
能源存储
✓ 已验证
DOI
高影响因子
Molecular Catalysis
·
2023
·
IF 4.6
Ye Tian,Yunchao Feng,Zheng Li,Yi Fan,Jonathan Sperry,Yong Sun,Shuliang Yang,Xing Tang,Lu Lin,Xianhai Zeng
The selective hydrogenation of the C=O group in biomass-derivate furfural (FF) over noble metal-free catalysts is challenging in aqueous. Herein, a CoO x /Nb 2 O 5 nanostructure catalyst was synthesized for the hydrogenation of FF to furfuryl alcohol (FA). Under optimized conditions, a 95.7% yield of FA was obtained with a TOF of 155.7 h −1 , and the kinetic study revealed that the reaction followed a pseudo-first-order pathway with an activation energy of 39.42 kJ mol −1 . The catalyst characterization indicated the interaction between Nb 2 O 5 and CoO via the Nb-O-Co bond in CoO x /Nb 2 O 5 -ctr, which prevented the further reduction of CoO to metal Co in the catalyst's preparation process. The catalytic mechanism suggested CoO was the dominant hydrogenation/adsorption active, whilst Co 3 O 4 and Nb 2 O 5 assisted the adsorption of FF. Further, DFT calculations verified CoO was the main adsorption site for FF adsorption in CoO x /Nb 2 O 5 -ctr. Moreover, CoO x /Nb 2 O 5 -ctr showed outstanding recyclability for the selective hydrogenation of FF to FA ever after five runs. This work provides opportunities for the clean conversion of biomass-based FF to FA and infers potential applications of Co for the large-scale hydrogenation of bio-based platform chemicals.
研究领域:
化学工程
·
催化化学
·
生物质转化
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Li-Wen Mao,Li-Yuan Zhu,Tao Tao Wu,Lei Xu,Xuan-Hong Jin,Hong-Liang Lu
Heterostructured Nb 2 O 5 /SnO 2 core-shell nanorods are synthesized by a facile hydrothermal strategy and atomic layer deposition (ALD). The SnO 2 shell thicknesses varying from 7 to 34 nm exhibit a significant impact on sensing performance. The response enhancement mechanism of the Nb 2 O 5 /SnO 2 core-shell nanorods is illustrated based on the electron-depletion model. The Nb 2 O 5 /SnO 2 core-shell nanorods gas sensors were synthesized based on the micro-electromechanical systems (MEMS), which could provide variable operating temperatures for the gas sensors with highly integrated design and low power consumption. The response of the Nb 2 O 5 /SnO 2 core-shell nanorods gas sensor deposited with 20 nm SnO 2 shell towards 20 ppm H 2 S at 275 °C was 4.0, which showed a 3.8-fold of improvement compared with pristine Nb 2 O 5 nanorods. Furthermore, the well-structured core-shell nanorods gas sensors maintained stable performance after three months, presenting long-term stability and repeatability. The proposed Nb 2 O 5 /SnO 2 core-shell nanorods gas sensors demonstrate a potential strategy for the practical application in oil and gas drilling platforms and other industrial fields.
研究领域:
材料科学
·
化学工程
·
传感器技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Fei Zhao,Yixin Guo,Xiang Wang,Jiahua Tao,Zeng Li,Dongliang Zheng,Jinchun Jiang,Zhigao Hu,Junhao Chu
Facile electron injection and extraction are two important attributes desired in electron transportation layer (ETL) to improve the power conversion efficiency (PCE) of planar CsPbBr 3 perovskite solar cell (PSC). Here, it is demonstrated that Li-doping of amorphous compact Nb 2 O 5 (Li: Nb 2 O 5 ) can effectively increase the electronic conductivity and facilitate the charge extraction with low recombination. Comparing with the PSC with Nb 2 O 5 ETL, the PCE of the Li: Nb 2 O 5 -based PSC is enhanced from 5.79% to 7.06%. Furthermore, the Li: Nb 2 O 5 -based CsPbBr 3 PSC exhibits a fabulous stability when exposed in air with moisture of ∼40% for 60 days. This work shows that ion doping provides new opportunities for preparing effective ETLs and high-performance inorganic PSCs .
研究领域:
材料科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2021
·
IF 5.302
Xiaohui Wu,Jingkang Xu,Xingyu Huo,Junbo Chen,Qin Zhang,Fangyi Huang,Yuanxun Li,Hua Su,Lezhong Li
This work investigates the influence of niobium pentoxide (Nb 2 O 5 ) as dopant , on the structural, magnetic, and dielectric properties of NiZnCo ferrites. The results showed that Nb 2 O 5 was an effective dopant, and the Nb 5+ ions entered the B site to replace Fe 3+ ions, which altered the electromagnetic properties of the NiZnCo ferrite. In particular, the coercivity ( H c ) was 20∼24 Oe, and the magnetic quality factor ( Q ), was more than 200 at x = 0 and x = 0.1 wt%, which is 4∼5 times higher than that of NiZn and NiCuZn ferrites. Excellent electromagnetic properties were obtained for 0.1 wt% Nb 2 O 5 -doped NiZnCo ferrite, i.e. , M s = 88.3 emu/g, H c =20.4 Oe, ρ = 2.4 × 10 5 Ω m and Q = 202 @20 MHz. These excellent electromagnetic properties of Nb 2 O 5 -doped NiZnCo ferrites could be potentially applied to resonators and capacitors at high frequency.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
Frontiers in Energy Research
·
2021
·
IF 4.008
Tong Le,Cai Bo,Zhang Ronghua,Feng Junfeng,Pan Hui
Nb2O5-supported bimetallic catalysts were prepared by the impregnation method applied for the in situ hydrogenation of guaiacol. Guaiacol can be effectively transformed into cyclohexanol over different bimetallic catalysts using alcohol as the hydrogen donor. Meanwhile, the effects of different hydrogen donors such as isopropanol, sec-pentanol, and ethylene glycol on in situ hydrogenation of guaiacol were investigated in detail, and the results showed that isopropanol is the best hydrogen supply solvent. Then, the dependence of Ni–Mn/Nb2O5 properties on metal loading, reaction time, reaction temperature, and reaction pressure was studied for the in situ hydrogenation of guaiacol by using isopropanol as the hydrogen donor. Guaiacol can be completely converted, and the yield of cyclohexanol reached 71.8% over Ni–Mn/Nb2O5 with isopropanol as the hydrogen donor at 200°C for 5 h. The structures and characteristics of better catalytic properties of the Ni–Mn/Nb2O5 catalyst were determined by BET, NH3-TPD, XRD, XPS, SEM, and TEM, and the results indicated the particle size of the metal was small (approximately 10 nm) and the metal particles are finely dispersed in the whole support. Therefore, a large number of medium acid sites were generated on the 10Ni-10Mn/Nb2O5 with a large specific surface area, which could increase the interface between the metal and the support and may be beneficial to the hydrodeoxygenation of guaiacol.
研究领域:
催化化学
·
可再生资源转化
✓ 已验证
产品关联
DOI
高影响因子
Chemistry-An Asian Journal
·
2025
·
IF 3.3
Guangyao Li,Xinghua Zhang,Qi Zhang,Lungang Chen,Jianguo Liu,Longlong Ma
The hydrodeoxygenation (HDO) of lignocellulose-based furan compounds holds significant potential for the synthesis of aviation fuel. However, challenges such as high catalyst costs and low yields persist. This study proposes a two-step strategy, involving pre-hydrogenation followed by HDO, to convert the C 15 condensation product derived from furfural and levulinic acid into hydrocarbons within the aviation fuel range. A Ni-based catalyst supported on zirconium phosphate (ZrP) with the incorporation of Nb 2 O 5 was synthesized. At 340 °C, 4 MPa H 2 , and weight hourly space velocity (WHSV) = 14.9, using Ni-Nb 2 O 5 /ZrP as the catalyst for HDO, considering the pre-hydrogenation, the overall yield of alkanes in the C 10 –C 15 jet fuel range from solid condensation products FLF is 62.4%, with a yield of C 15 alkanes of 16.2% and C 14 alkanes of 25.2%. A series of characterizations and comparative experiments were carried out. Experimental studies have demonstrated that doping with Nb 2 O 5 plays a crucial role in enhancing the HDO performance. The characterization results indicate that the introduction of an appropriate amount of Nb 2 O 5 increased the electron density of ZrP, enriched the catalyst's acidic sites, in addition, the ratio of Bronsted acid to Lewis acid sites in the catalyst increases. Finally, a brief analysis of industrialization potential was conducted.
研究领域:
化学工程
·
可再生能源
·
催化科学
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）