Catalysts
·
2020
·Vol. 10
·期 12
·1480
·
IF 3.52
Wei Guo,Libin Yang,Jinghao Lu,Peng Gao,Wenjing Li,Zhiying Feng
To effectively improve photocatalytic activity, the morphology and crystallinity of semiconductor photocatalysts must be precisely controlled during the formation process. Self-aligned Nb2O5nanotube arrays have been successfully fabricated using the electrochemical anodization method. A novel growth mechanism of Nb2O5nanotubes has been proposed. Starting from the initial oxidation process, the “multi-point” corrosion of fluoride ions is a key factor in the formation of nanotube arrays. The inner diameter and wall thickness of the nanotubes present a gradually increasing trend with increased dissociative fluorine ion concentration and water content in the electrolyte. With dehydroxylation and lattice recombination, the increased crystallinity of Nb2O5represents a reduction of lattice defects, which effectively facilitates the separation and suppresses the recombination of photo-generated carriers to enhance their catalytic degradation activity.Keywords:Nb2O5;nanotube;growth mechanism;crystalline;photocatalysis
研究领域:
材料科学
·
环境科学
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DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2024
·
IF 20.2
Shiyong Mou,Siyuan Liu,Weidong Dai,Yanjuan Sun,Fan Dong
Electrochemical oxidative amidation (EOA) strategies offer a sustainable and potentially promising route for amide synthesis. However, the efficiency and activity of catalysts under oxidative conditions are highly dependent on noble metals. Herein, we present our experimental findings and fundamental understanding that fluorine-doped Nb 2 O 5 nanosheet arrays on carbon paper (F-Nb 2 O 5 /CP) serve as an efficient and robust non-noble catalyst for the electrochemical synthesis of formamide from ammonia and methanol under ambient conditions. In 0.5 M KHCO 3 solution, this catalyst achieved a high Faradaic efficiency of 52.0 %, with an N selectivity of 79.1 % at 1.5 V versus Hg/HgO electrode. The catalyst exhibited remarkable stability, maintaining its performance over 120 h. By integrating in-situ spectroscopy studies with density functional theory calculations, we revealed that fluorine doping induces a shift in the d-band center of the Nb site. This shift alters the adsorption behavior of OH - and *NH 2 intermediate on the F-Nb 2 O 5 (100) surface, thereby effectively lowering the C-N coupling energy barrier, and boosting the production of formamide.
研究领域:
材料科学
·
电化学
·
催化化学
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产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2026
·
IF 6.7
Xiaowen Wang,Jing Bai,Jiaying Chen,Shijie Cao,Quanquan Li,Boyu Zhang,Zhixue Wang,Hexiang Lu,Jianyou Wang,Xuesong Wang,Yunhua Xu
Ni-loaded Ce/Nb oxide catalysts (CeNb-x%Ni) were prepared and ball-milled with MgH 2 under H 2 to investigate the effects of Ni loading on sorption kinetics. The results reveal that the 40%Ni catalyst featured the most balanced behavior. MgH 2 -10%(CeNb-40%Ni) absorbed 5.516 wt% H 2 within 1 min at 350 °C and released approximately 5.6 wt% H 2 within 30 min after hydrogenation. At 150 °C, it still absorbed 3.54 wt% H 2 in 6.5 min and reached 4.921 wt% after 30 min. TPD and DSC curves suggest that the onset and main release temperatures moved to lower values, while kinetic analysis presented a much smaller apparent dehydrogenation barrier. XPS indicates the presence of Mg-H-related species, metallic/interfacial and oxidized Ni species, Ce 3 + /Ce 4+ surface states, and Nb 5+ /Nb δ⁺ -related components. These surface states, together with the refined particles and crack/pore-rich surface produced during milling and cycling, may facilitate hydrogen transfer across the MgH 2 /catalyst interface. Thus, an appropriate Ni amount in a Ce/Nb oxide matrix is important for accelerating MgH 2 absorption and desorption.
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Lin-Jie Guo,Yi-Lei Li,Feng Xu,Yuan Zhuang,Xuan-Ru Zhang,Zu-Heng Hu,Le-Zhong Li
This study investigates the effects of co-doping Bi 2 O 3 and Nb 2 O 5 on the microstructure, electrical, and magnetic properties of NiZnCo ferrites. The NiZnCo ferrites with fixed 0.3 wt.% Bi 2 O 3 doping and different Nb 2 O 5 doping contents (0–0.8 wt.%) were synthesized by state-phase reaction method. The study shows that all Ni 0.55 Zn 0.35 Co 0.1 Fe 2 O 4 samples co-doped with Bi 2 O 3 and Nb 2 O 5 exhibit a single-phase spinel structure. With increasing Nb 2 O 5 concentration, the average grain size of the ferrites increases continuously, while the porosity decreases. Furthermore, the real part of the dielectric constant rises to 2.42×10 5 , and the DC resistivity decreases to 3.08×10 5 Ω·m. The saturation magnetization varies from 40.78 to 53.29 emu/g, and the coercivity ranges from 18.00 to 19.14 Oe. Notably, among samples with different Nb 2 O 5 doping levels, the ferrite co-doped with 0.2 wt.% Nb 2 O 5 exhibits the highest initial permeability of 111.24, which is approximately four times higher than that of pure NiZnCo ferrite. These results indicate that Bi 2 O 3 –Nb 2 O 5 co-doping not only effectively regulates grain growth and porosity but also achieves a synergistic optimization of dielectric and magnetic properties. The introduction of an appropriate amount of Nb 2 O 5 leads to high initial permeability and moderate DC resistivity, helping to reduce mismatches between magnetic and dielectric losses. The combination of high dielectric constant and favorable magnetic response enhances the impedance matching and energy dissipation capabilities of the material for electromagnetic waves. Therefore, this co-doped ferrite offers a promising material candidate for the design of electromagnetic absorbers and soft magnetic components.
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高影响因子
Materials
·
2021
·Vol. 14
·期 14
·3783
·
IF 3.623
Jian-Ping Qiu,Huan-Qing Xie,Ya-Hao Wang,Lan Yu,Fang-Yuan Wang,Han-Song Chen,Zheng-Xin Fei,Chao-Qun Bian,Hui Mao,Jia-Biao Lian
The removal of organic pollutants using green environmental photocatalytic degradation techniques urgently need high-performance catalysts. In this work, a facile one-step hydrothermal technique has been successfully applied to synthesize a Nb2O5photocatalyst with uniform micro-flower structure for the degradation of methyl orange (MO) under UV irradiation. These nanocatalysts are characterized by transmission and scanning electron microscopies (TEM and SEM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) method, and UV-Vis diffuse reflectance spectroscopy (DRS). It is found that the prepared Nb2O5micro-flowers presents a good crystal phases and consist of 3D hierarchical nanosheets with 400–500 nm in diameter. The surface area is as large as 48.6 m2g−1. Importantly, the Nb2O5micro-flowers exhibit superior catalytic activity up to 99.9% for the photodegradation of MO within 20 mins, which is about 60-fold and 4-fold larger than that of without catalysts (W/O) and commercial TiO2(P25) sample, respectively. This excellent performance may be attributed to 3D porous structure with abundant catalytic active sites.
研究领域:
材料科学
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环境化学
·
纳米催化
·
光化学
·
功能材料
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DOI
高影响因子
Nature Communications
·
2025
·Vol. 16
·期 1
·1-12
·
IF 15.7
Xu Junling,Xie Fuqiang,Huang Lipeng,Li Nana,Peng Shang,Ma Wensheng,Zhang Kai,Wu Yanxue,Shao Lianyi,Shi Xiaoyan,Chen Jizhang,Tao Li,Zhang Kai,Zhang Zhonghua,Wang Yonggang,Sun Zhipeng
Doping is an important approach to tailor materials’ properties, yet the success of doping can depend on factors such as ionic radii similarities. For materials like silicon or perovskite, doping is not only facile to implement but can also enhance material properties. However, for host lattice structures like Nb 2 O 5 , doping without causing phase change is challenging. Here, we introduce a high-entropy-doping effect in Nb 2 O 5 . Unlike traditional doping approaches, high-entropy-doping minimizes the chemical properties of doping elements and focuses solely on their quantities. By high-entropizing the doping elements (selecting 10–15 from Mg, Ca, Sr, Ba, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Ga, In, Sn, Sb, Y, Mo, La, Ce) and keeping them within a certain range of doping concentrations (1–3 mol %), a successful high-entropy-doping is achieved for Nb 2 O 5 without phase change. The obtained high-entropy-doped (HED) Nb 2 O 5 exhibits rapid-charging capabilities. At a rate of 40 A g −1 , the HED-Nb 2 O 5 delivers a capacity of 80 mAh g −1 , whereas the undoped Nb 2 O 5 fails to exceed 25 mAh g −1 .
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DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2023
·Vol. 58
·期 2
·707-717
·
IF 4.5
Sui Yudong,Yuan Yanru,Tan Pan,Jiang Yehua,Han Lina
This paper presents the experimental investigation of the effect of Nb 2 O 5 content on the phase composition, microstructure, and physical and mechanical performance of the zirconia-toughened alumina (ZTA) ceramics, aimed to optimize the additional amount of Nb 2 O 5 , refine the ceramic grains, and improve the densification, hardness and fracture toughness. ZTA ceramics with various Nb 2 O 5 contents were prepared using the spark plasma sintering method. The addition of trace amounts of Nb 2 O 5 did not produce a new Nb-rich phase; the Nb atoms were dissolved in the ZrO 2 grains. The addition of trace amounts of Nb 2 O 5 led to grain refinement and an increase in density, but the addition of excessive Nb 2 O 5 resulted in grain growth and a decrease in relative density. Furthermore, the addition of Nb 2 O 5 promoted uniformity of the microstructure. The sample with 0.25 wt.% Nb 2 O 5 had the maximum Vickers hardness and indentation fracture toughness, which were 1228.40 HV and 9.17 MPa √m, respectively. Mechanical properties of the composite mainly depended on the grain size, which was influenced to some extent by the relative density.
研究领域:
材料科学
·
无机非金属材料
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陶瓷学
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结构陶瓷
·
粉末冶金
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DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2017
·
IF 5.951
Huili Zhang,Qi Wu,Cong Guo,Ying Wu,Tinghua Wu
The photocatalytic selective oxidation of biomass derivate compound 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran is an environmentally friendly and energy-saving process. Nb2O5 was prepared and applied in the oxidation of HMF under visible light, although its bandgap energy is higher than 3.2 eV. The reaction process follows a special mechanism over a Nb2O5 catalyst different from the normal oxide semiconductor. The effect of calcination temperature, incident wavelength, and reaction time on photocatalytic performance was investigated. Nb2O5-800 exhibits the best performance in the presence of O2 with benzotrifluoride as a solvent under visible light irradiation.
研究领域:
化学工程
·
环境科学
·
材料科学
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产品关联
DOI
高影响因子
ACS Catalysis
·
2019
·
IF 12.221
Kaiyi Su,Huifang Liu,Bin Zeng,Zhixin Zhang,Nengchao Luo,Zhipeng Huang,Zhuyan Gao,Feng Wang
Photocatalytic selective oxidation of hydrocarbons to oxygenated chemicals greatly relies on catalytic materials that show high efficiency of photogenerated holes and electrons separation and visible light absorption capacity. We, herein, report one facile calcination approach with ammonium chloride and melamine as the template to synthesize nitrogen-modified Nb2O5 nanomeshes material (Nb2O5-N), which exhibits a 37-fold reaction rate larger than its commercial counterpart in photocatalytic oxidation of toluene into benzaldehyde under visible light irradiation. The reactivity is ascribed to an extended absorption spectrum within 700 nm by nitrogen modification. In addition, photocurrent response results suggest that a relaxation effect induced by nanomesh structure is beneficial for the separation of charge carriers for enhanced reactivity. This work sheds light on regulating the structure of metal oxides and the application of nanomesh materials in photocatalytic hydrocarbon conversion.
研究领域:
材料科学
·
化学工程
·
环境科学
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产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2023
·
IF 7.3
Hao Xu,Hao Li
Constructing heterogeneous catalysts with high efficiency and stability to achieve biomass HDO under comparatively mild conditions is an arduous challenge. Crystal phase of metal oxides supports could affect the geometric and electronic properties, causing the variation of catalytic performance. Herein, a series of Pd/Nb 2 O 5 catalysts of pseudohexagonal crystal phase (Nb 2 O 5 -TT), orthorhombic phase (Nb 2 O 5 -T) and monoclinic phase (Nb 2 O 5 -H) are prepared through regulating the annealing temperature. Impressively, Pd/Nb 2 O 5 -T catalyst showed amazing catalytic performance of 100% conversion and 98.9% selectivity of 2-methoxy-4-methylphenol (MMP) at room temperature (25℃) within 30 min, superior than Pd/Nb 2 O 5 -TT, Pd/Nb 2 O 5 -H and other Pd-based catalysts that had been reported. Besides, the Pd/Nb 2 O 5 -T perform robust stability and maintain its high activity after ten times recovery experiment. This catalytic system is also suitable for different kinds of aldehydes compounds at room temperature, exhibiting the high activity and selectivity towards deoxygenated products. Based on the characterizations and experimental validations, it has confirmed that the strong metal-support interaction (SMSI) effect generates via electron transfer between Pd species and Nb 2 O 5 -T support, where in situ reduction of PdO occurred during the reaction, generating active interfacial Pd-O-Nb sites and accelerating the breaking of C-O bonds. The insights of this work provide a guiding direction for the future design of highly selective heterogeneous catalysts by crystal phase modulation engineering.
研究领域:
催化化学
·
材料科学
·
能源化学
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Lulu Wang,Beiyue Ma,Xinming Ren,Chao Yu,Chengji Deng,Chunming Liu,Chuanbo Hu
In an attempt to enhance the sintering and mechanical performance of porous cordierite ceramics (Mg 2 Al 4 Si 5 O 18 ) as support materials for vehicle exhaust catalysts, ZrO 2 and M x O y (M = La, Ce, and Nb) were simultaneously introduced into cordierite sintered at 1350 °C for 4 h. Then, the reinforced function of ZrO 2 and M x O y on the properties of porous cordierite ceramics was systematically evaluated, especially for the sample co-doped with ZrO 2 and La 2 O 3 . The results displayed a distinct enhancement in mechanical and thermal performance, and the cold compressive strength increased from 72.74 to 158.59 MPa as well as thermal conductivity ranged from 1.66 to 2.01 W m −1 K −1 , respectively. It is found that ZrO 2 facilitated activation sintering introduced via lattice distortion in cordierite and La 2 O 3 accelerated the formation of cordierite and ZrSiO 4 microcrystalline through the low-temperature liquid phase. The synergic effect between ZrO 2 and La 2 O 3 , therefore, had a significant role in the reinforced mechanical and thermal performance of porous cordierite ceramics. This work not only offers a feasible strengthening strategy, but also expands the possibilities for building high-performance structural and functional ceramics .
研究领域:
材料科学
·
陶瓷工程
·
汽车工程
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DOI
高影响因子
Minerals
·
2023
·Vol. 13
·期 3
·387
·
IF 2.5
Min Zhang,Fangfang Chen,Guoying Yan,Hongjing Li,Jing Li,Guan Peng,Hongdong Yu
The characteristics of Baiyun Obo niobium-bearing minerals are complex physicochemical properties that make the beneficiation of niobium minerals extremely difficult. In this paper, X-ray diffraction, X-ray fluorescence and mineral liberation analyzer (MLA) systems were used to study the niobium occurrence state and distribution of niobium-bearing minerals in the samples from Baiyun Obo. The results show that the chemical and mineral compositions of the sample are complex, with a Nb2O5grading of 0.24%. There are many kinds of niobium minerals, including ilmenorutile, nioboaeschynite-Nd, baotite, latrappite, euxenite-Y, fergusonite and columbite-Mn, and the highest mass fraction of 0.55% is achieved with Nb in nioboaeschynite-Nd, followed by the mass fraction of ilmenorutile (0.33%). All of the niobium-containing minerals demonstrate a low degree of dissociation. Flotation experiments explored the optimal flotation conditions for HOBA (1-hydroxyoctyl-1,1-bisphosphonic acid) as a flotation collector for Baiyun Obo niobium minerals, which is able to increase the grade of Nb2O5in the concentrate to 1.31%. The optimal use conditions of the reagent are pH 3.5–4.5, and the amount of the collector is 1000 g/t. By further optimizing the beneficiation process and reagent system, ilmenorutile and nioboaeschynite-Nd were significantly enriched in the concentrate, which suggested that HOBA can efficiently increase the grade of Nb2O5in the concentrate.Keywords:MLA;distribution regularity;flotation;niobium;Baiyun Obo
研究领域:
矿物加工
·
地球化学
·
材料科学
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DOI
高影响因子
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