APPLIED CATALYSIS A-GENERAL
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2023
·
IF 5.5
Bingjie Ding,Yongjun Jiang,Beibei Xu,Sheng Dai,Honghui Gong,Xiuge Zhao,Yefeng Yao,Pengfei An,Zhenshan Hou
This work demonstrated a facile methodology to construct single Nb site catalysts with merely 0.63 wt% Nb by employing α-hydroxy carboxylic acid-functionalized cotton fiber as green and sustainable supporting material. The as-synthesized catalysts have been characterized thoroughly and exhibited a superior catalytic activity for selective oxidation of aniline into azoxybenzene with nearly 100% utilization efficiency of H 2 O 2 under mild and green conditions. Notably, it demonstrated the highest TOF (4806 h −1 ) among the currently reported heterogeneous catalysts. Moreover, the catalyst has steadily been operated under continuous-flow conditions, which afforded significant benefits compared to batch processes as reported in these transformations. The activity test and catalyst characterization indicated that the atomically dispersed Nb-peroxo coordination centers were actually catalytic sites. Especially, the α-hydroxy carboxylic acid groups on cotton fiber played an important role in coordinating/stabilizing single Nb site. Moreover, 1 H MAS NMR spectra verified that there exists an acid-base interaction between arylamines and free α-hydroxy carboxylic acid groups covalently grafted on cotton fiber, which was favorable for adsorption and activation of the substrates. Mechanism studies indicated that the azoxy derivatives were produced through condensation step between N-phenylhydroxylamine and nitrosobenzene rather than direct oxidation of azobenzene . The work provides an economical and environmentally friendly approach to construct single–site catalysts for the oxidation catalysis.
研究领域:
催化化学
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绿色化学
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材料科学
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产品关联
DOI
高影响因子
Small
·
2023
·Vol. 19
·期 20
·2207569
·
IF 13.3
Yakun Tian,Ming Wen,Aijian Huang,Qingsheng Wu,Zhiguo Wang,Quanjing Zhu,Tao Zhou,Yongqing Fu
High stability and efficiency of electrocatalysts are crucial for hydrogen evolution reaction (HER) toward water splitting in an alkaline media. Herein, a novel nano-Pt/Nb-doped Co(OH) 2 (Pt/Nb Co(OH) 2 ) nanosheet is designed and synthesized using water-bath treatment and solvothermal reduction approaches. With nano-Pt uniformly anchored onto Nb Co(OH) 2 nanosheet, the synthesized Pt/Nb Co(OH) 2 shows outstanding electrocatalytic performances for alkaline HER, achieving a high stability for at least 33 h, a high mass activity of 0.65 mA µg −1 Pt, and a good catalytic activity with a low overpotential of 112 mV at 10 mA cm −2 . Both experimental and theoretical results prove that Nb-doping significantly optimizes the hydrogen adsorption free energy to accelerate the Heyrovsky step for HER, and boosts the adsorption of H 2 O, which further enhances the water activation. This study provides a new design methodology for the Nb-doped electrocatalysts in an alkaline HER field by facile and green way.
研究领域:
材料科学
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电化学
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产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2023
·Vol. 12
·期 4
·2349-2358
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IF 11.9
Kefan Liu,Zhaoyu Wang,Guanqi Wang,Xinyi Zhang,Ping He,Yuhui Huang,Zijian Hong,Haiwang Wang
To enhance the photocatalytic hydrogen evolution reaction (HER) activity and stability of barium–strontium–titanate (Ba0.7Sr0.3TiO3, BST), niobium (Nb5+) donor doped BST (Ba0.7Sr0.3Ti1−xNbxO3) photocatalysts were synthesized via a sol–gel assisted solid phase method. It was found that the introduction of Nb5+ expands the lattice and impedes grain growth. In the mechanism of enhancing photocatalytic performance, on one hand, the doped Nb5+ ions generate two types of defects in the lattice of BST, which form defect dipoles to impede electron–hole recombination and improve the stability of photocatalytic performance. On the other hand, the temperature stability test of the dielectric constant shows that appropriate doping of Nb5+ ions will enhance the stability of carrier concentration in BST, thereby exhibiting superior HER activity. In terms of band structure, experiments and Density Functional Theory (DFT) confirmed that the doping of trace amounts of Nb5+ has a very weak influence on the band structure. Additionally, the photocatalytic hydrogen evolution of 1% Nb doped Ba0.7Sr0.3TiO3 was 16.2% higher than that of Ba0.7Sr0.3TiO3.
研究领域:
材料科学
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能源科学
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产品关联
DOI
高影响因子
Functional Materials Letters
·
2025
·
IF 1.1
Jie Zhao,Ming Guan,Can Cui,Saifang Huang
To enhance the room-temperature lithium-ion conductivity and interfacial stability of Li 7 La 3 Zr 2 O 1 2 (LLZO) solid-state electrolytes, a co-doping strategy with Ga 3 + and Nb 5 + was employed. By systematically optimizing the sintering protocol — including heating rate, temperature, and dwell time — highly dense and phase-pure cubic-phase LLZO ceramics were successfully synthesized. The co-doping approach effectively stabilized the cubic garnet structure and regulated the lattice framework to facilitate Li + transport pathways. Under optimized conditions, compared to undoped LLZO (0.31 mS cm − 1 , 0.362 eV), the co-doped ceramic exhibited significantly enhanced total ionic conductivity (0.81 mS cm − 1 ) and reduced activation energy (0.207 eV), confirming the superior transport performance enabled by the co-doping strategy. Furthermore, the electrolyte showed good wettability and interfacial compatibility with metallic lithium, enabling stable cycling performance in symmetric Li∥Ga/Nb-LLZO∥Li cells over short durations. These results confirm the practical potential of the co-doped LLZO electrolyte in all-solid-state lithium batteries. This study provides a viable pathway for the material design and processing of high-performance LLZO-based solid electrolytes.
研究领域:
材料科学
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固体离子学
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储能技术
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陶瓷工艺
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产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2017
·
IF 9.446
Lu Jiang,Shuang Ni,Gang Liu,Xiaoxiang Xu
In this work, we have applied Cr/Nb co-doping strategy to the wide band gap semiconductor Bi 3 TiNbO 9 and have performed a detailed investigation on the structure, optical and photocatalytic properties of these modified Aurivillius compounds Bi 3 Ti 1-2x Cr x Nb 1+x O 9 (x = 0, 0.1, 0.2, 0.3). Our results suggest that Cr/Nb doping slightly expand the unit cell of Bi 3 TiNbO 9 with a doping limit around 20%. The involvement of Cr/Nb dopants in the crystal structure significantly reduces the band gap of Bi 3 TiNbO 9 by nearly 1 eV. Photocatalytic experiments and photoelectrochemical measurements confirms the critical role of Cr/Nb dopants in improving photocatalytic hydrogen production and anodic photocurrent. More than two-fold enhancement in hydrogen production has been noticed for merely 10% Cr/Nb co-doping. The highest photocatalytic activity belongs to Bi 3 Ti 0.8 Cr 0.1 Nb 1.1 O 9 (x = 0.1) for full range illumination and to Bi 3 Ti 0.6 Cr 0.2 Nb 1.2 O 9 (x = 0.2) for visible light illumination, with apparent quantum efficiency (AQE) approaching 0.52% and 0.27%, respectively. DFT calculation discloses the role of Cr in forming a new valence band inside the band gap of Bi 3 TiNbO 9 . In addition, strong anisotropic phenomenon in charge transportation of Bi 3 TiNbO 9 is also verified by DFT, as both conduction band minimum (CBM) and valence band maximum (VBM) are buried in the [BiTiNbO 7 ] 2− perovskite slabs and charges are only allowed to migrate within the slabs.
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DOI
高影响因子
ELECTROCHIMICA ACTA
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2018
·
IF 5.116
Congjie Lv,Jing Yang,Yi Peng,Xiaochuan Duan,Jianmin Ma,Qiuhong Li,Taihong Wang
The effect of niobium (Nb) doping in one-dimensional (1D) nanostructured LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NCM) cathode has been investigated for this study. Nb-doped NCM nanofibres have been prepared through an electrospinning method followed by controllable sintering process . X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results confirmed that Nb-doping can effectively reduce cation mixing, thus improve the structural stability . In addition, due to the valence compensation balance, Mn 4+ ions are partially reduced to Mn 3+ ions, which can further improve the conductivity and stable cycling performance. Therefore, increased discharge capacities, high first cycle efficiencies and superior cycling and rate behaviors are observed between normal voltage limits for the Nb-doped NCM compositions in electrochemical cells . Specifically, Nb-doped NCM nanofibres achieve a high discharge capacity of 200.4 mAh/g at 0.1 C with a high Coulombic efficiency of 92.3%. Moreover, a high discharge capacity of 118.7 mAh/g even at 5 C with 83.3% capacity retention after 200 cycles is also achieved. Also, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) results demonstrate that Nb-doping can mitigate the electrochemical polarization of NCM and improve the lithium ion diffusion coefficient , leading to the improvement of electrochemical performances . It is highly expected that our findings can provide a general approach to improve the electrochemical properties of cathode materials for lithium-ion batteries.
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高影响因子
JOURNAL OF ELECTRONIC MATERIALS
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2022
·Vol. 51
·期 12
·6885-6893
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IF 2.047
Song Angang,Cao Guoqin,Zhu Di,Zhao Baofeng,Fu Zhenya,Cao Shuaiqi,Wang Qingjie,Hu Junhua
Nb-doped TiO 2 (NTO) thin films were sputtered on glass substrate followed by a simple annealing process in air. The photoelectric cooperative optimization was discussed based on the structural, optical and electrical characteristics. The influence of oxygen flow during deposition on materials chemistry and performance was analyzed. Hall measurement showed a strong dependence of transparent conductivity on the oxygen flow. Oxygen vacancies are related to the phase transitions from the rutile to anatase TiO 2 during annealing. The chemical states of Nb, Ti and O before and after annealing were discussed. The achievement of optimized transparent conductivity was resultant from the fine-tuning of the doped chemistry and special interplay of dopants and host lattice. Graphical
研究领域:
材料科学
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薄膜技术
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固体物理
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光电材料
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无机非金属材料
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DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Xuansheng Wang,Muzi Liu,Tian Tian,Fang Liu,Jiali Wang,Jinping Li,Guang Liu
MgH₂ is recognized as one of the most promising solid hydrogen storage materials; however, its practical application is confined by sluggish kinetics and stable thermodynamics. In this study, fibrous VNbO₅ was synthesized via electrospinning and subsequently introduced into MgH₂ through ball milling technology to enhance hydrogen storage properties. The addition of 7 wt% VNbO₅ give rise to the obvious decline in the initial dehydrogenation temperature of MgH₂, from 322.2 °C to 200.2 °C. At 300 °C, the modified composite exhibited rapid dehydrogenation, releasing approximately 6.43 wt% hydrogen within 8.1 min. Moreover, the fully dehydrogenated sample demonstrated the ability to absorb hydrogen at room temperature and absorbed 6 wt% H₂ at 200 °C within 16 s. The desorption activation energy of the MgH₂-7 wt% VNbO₅ composite was determined to be 75.32 ± 1.44 kJ/mol, representing an approximate 48.1% reduction compared to the 145.25 ± 2.14 kJ/mol of pure MgH₂. Furthermore, the system possessed remarkable cyclic stability, retaining 95.5% of hydrogen storage amount after 20 cycles. During the reaction process, VNbO₅ decomposed into low-valence state active catalytic species, including Nb₂O₅, NbO, Nb, VO₂, and V. The in-situ generation of this multi-element, multi-valence chemical environment synergistically enhanced hydrogen storage performance of MgH₂.
研究领域:
材料科学
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能源存储
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DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
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2023
·Vol. 106
·期 7
·4382-4389
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IF 3.9
Yongqiang Tan,Wei Liao,Zhen Teng,Haibin Zhang
Two high-entropy carbides, including stoichiometric (Zr,Ti,Nb,Ta,Hf)C and nonstoichiometric (Zr,Ti,Nb,Ta,Hf)C 0.8 , were prepared from monocarbides and ZrH 2 . Their sinterability, microstructures, mechanical properties, thermophysical properties, and oxidation behaviors were systematically compared. With the introduction of carbon vacancy, the sintering temperature was lowered up to 300°C, Vickers hardness was almost unaffected, whereas the strength decreased significantly generally due to the decrease of covalent bonds. The thermal conductivity shows a 50% decrease for nonstoichiometry high-entropy carbide, which is a major consequence of the lower electrical conductivity. The oxidation resistance in high temperature water vapor was not sensitive to carbon stoichiometry.
研究领域:
材料科学
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机械工程
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DOI
高影响因子
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Liang Dan,Hui Wang,Xiaobao Yang,Jiangwen Liu,Liuzhang Ouyang,Min Zhu
The practical applications of MgH2 as a high-density hydrogen carrier depend heavily on efficient and low-cost catalysts to accelerate the dehydriding/hydriding reactions at moderate temperatures. In the present work, this issue is addressed by synthesizing Nb-doped TiO2 solid-solution-type catalysts that dramatically improve the hydrogen sorption performances of MgH2. The catalyzed MgH2 can absorb 5 wt % of H2 even at room temperature for 20 s, release 6 wt % of H2 at 225 °C within 12 min, and the complete dehydrogenation can be achieved at 150 °C under a dynamic vacuum atmosphere. Density functional theory calculations reveal that Nb doping introduces Nb 4d orbitals with stronger interaction with H 1s into the density of states of TiO2. This considerably enhances both the adsorption and dissociation ability of the H2 molecule on the catalysts surface and the hydrogen diffusion across the specific Mg/Ti(Nb)O2 interface. The successful implementation of solid solution-type catalysts in MgH2 offers a demonstration and inspiration for the development of high-performance catalysts and solid-state hydrogen storage materials.
研究领域:
材料科学
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催化化学
·
能源存储
✓ 已验证
DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2026
·
IF 9.6
Mao Zhang,Jiaqing Niu,Bo-Mei Liu,Rongfu Zhou,Haijiao Xie,Yingchun Liu,Wei Liu,Rui Zou,Hui Zhang,Jing Wang
Bioimaging is essential in medical diagnostics and research, yet conventional optical methods are limited by photobleaching and background interference. Although near-infrared (NIR) persistent luminescent (PersL) materials avoid in situ excitation and autofluorescence, their signal decay and shorter-wavelength emission restrict long-term repetitive imaging. Here, we report an oxygen-vacancy-tailoring strategy in LaInO 3 :Nb,Cr, which exhibits broad NIR emission centered at 845 nm, efficient X-ray charging, and repeatable red-light recharging. Benefiting from its high-atomic-number host, LaInO 3 exhibits strong X-ray absorption, while Nb 5+ doping modulates oxygen vacancy (V O ), thereby boosting Cr 3+ NIR PersL by approximately 13 times. In vivo imaging reveals that LaInO 3 :Nb,Cr nanoparticles can be reactivated with a low X-ray dose (0.20 Gy) and repeatedly recharged in situ by red light, highlighting their potential for deep-tissue imaging. This work provides insights into defect-property relationships via ion doping and offers guidance for the rational design of PersL materials for practical applications.
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DOI
高影响因子
CRYSTENGCOMM
·
2026
·
IF 2.4
Lei Wang,Jiapeng Wang,Yilin Wu,Jianyi Ma,Jinsheng Li,Xiaoguo Bi,Xudong Sun,Weiping Lu
Although widely recognized for its potential to deliver a colossal permittivity, the origins of this extraordinary property in SrTiO3 are still not fully clarified, necessitating further investigation. In this work, Nb-doped SrTiO3 single crystals were prepared by the Verneuil method, and the influence of different defect dipoles on their dielectric properties was systematically investigated. The study revealed that oxygen-vacancy-associated defect dipoles and are effective in localizing free electrons. Under these conditions, electronic polarization mediated by defect dipoles is present in all samples, contributing to a high permittivity while maintaining low loss. The concentration of these defect dipoles, and thus the dielectric performance, can be effectively tuned by varying the doping level and annealing atmosphere. Notably, defect dipoles capable of efficiently trapping free electrons lead to superior properties. Ultimately, the SrNb0.5%Ti99.5%O3 crystal annealed in an oxygen atmosphere tends to form more defect dipoles , yielding a permittivity of 63 217 and a loss tangent of 0.0208 at 1 kHz. This work provides crucial guidance for designing high-performance SrTiO3-based dielectric materials.
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DOI
高影响因子
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