CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2021
·
IF 3.171
Chunhua Zhang,Zhengyan Qu,Hong Jiang,Rizhi Chen,Weihong Xing
Phenol hydrogenation is a green route to prepare cyclohexanone, an intermediate for the production of nylon 66 and nylon 6. The development of high-performance catalysts still keeps a great challenge. Herein, the activated carbon (AC) was modified with an acidic material Nb 2 O 5 to adjust the microstructure and surface properties of AC, and the influences of the calcination temperature and Nb 2 O 5 content on the catalytic performance of the Pd/AC-Nb 2 O 5 catalysts for the phenol hydrogenation to cyclohexanone were investigated. The Nb 2 O 5 with proper content can be highly uniformly distributed on the AC surface, enhancing the acidity of the Pd/AC-Nb 2 O 5 catalysts with comparable specific surface area and Pd dispersion, thereby improving the catalytic activity. The hybrid Pd/AC-10Nb 2 O 5 -500 catalyst exhibits the synergistic effect between the Pd nanoparticles and AC-10Nb 2 O 5 , which enhances the catalytic activity for the hydrogenation of phenol. Furthermore, the as-prepared Pd/AC-10Nb 2 O 5 -500 catalyst shows good reusability during 7 reaction cycles.
研究领域:
化学工程
·
催化材料
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2016
·
IF 5.31
Yuanzhi Hong,Changsheng Li,Guangyi Zhang,Yadong Meng,Bingxin Yin,Yong Zhao,Weidong Shi
The removal of pollutant using photocatalysis technology has received much attention due to the increasing serious environmental contamination. In this study, novel Nb 2 O 5 /g-C 3 N 4 heterojunctions were fabricated via a facile one-step heating strategy for the first time. Compared to pure g-C 3 N 4 and Nb 2 O 5 , the as-prepared Nb 2 O 5 /g-C 3 N 4 samples exhibited remarkably enhancing photocatalytic activity for degradation of tetracycline hydrochloride (TC-HCl) both under visible and simulated solar light irradiation. It was found that the 3% Nb 2 O 5 content of heterojunction (3%NO/CN) showed the highest photocatalytic efficiency for TC-HCl degradation, which is about 2.9-fold and 2.4-fold higher than that of pristine g-C 3 N 4 under visible and simulated solar light irradiation, respectively. In addition, the 3%NO/CN sample not only displayed excellent photocatalytic recyclability, but also can efficiently remove TC-HCl even under strong acidic condition (pH = 1). Moreover, the 3%NO/CN heterojunction also exhibited dramatically enhancement of photocatalytic activity for degradation of other fluoroquinolones antibiotic, such as ciprofloxacin (CIP) and levofloxacin (LEV). The highly enhancing photoactivity was attributed to the formation of a heterojunction between g-C 3 N 4 and Nb 2 O 5 , which could greatly suppresses the photogenerated electron–hole pair’s recombination. The active species trapping and ESR experiments indicated that superoxide radicals and holes are the major active species in which contributing to the photocatalytic process. This work will bring about potential application in treatment of antibiotic pollutant and solar energy conversion.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2021
·
IF 19.503
Yingtong Zou,Yezi Hu,Andrej Uhrich,Zewen Shen,Baoxiang Peng,Zhuoyu Ji,Martin Muhler,Guixia Zhao,Xiangke Wang,Xiaoxiang Xu
We provide a distinct understanding on the role of oxygen vacancies (OVs) for visible light-triggered aerobic oxidation of alcohols via comparative studies on three kinds of Nb 2 O 5 , i.e., undoped, Ti-doped and Ce-doped Nb 2 O 5 . With benzyl alcohol and 5-hydroxymethylfurfural as representative alcohol substrates, we show that fast alcohol oxidation with high selectivity can be achieved on these doped Nb 2 O 5 containing abundant OVs. However, the functionality of OVs is dependent on the properties of dopants as Ce-doped Nb 2 O 5 exhibits a better performance than Ti-doped one. Investigations indicate that the Ce dopants incur little distortion to the structure of Nb 2 O 5 and induce more accessible OVs than Ti dopants for the dissociative chemisorption of alcohol molecules which supports favorable interfacial electron migration process. The present work not only reveals the difference of oxygen vacancies caused by varied metal doping but provides a unique insight in the relation between OVs structure and photocatalytic alcohol oxidation.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2024
·Vol. 17
·期 23
·5824
·
IF 3.1
Guoyu Zhang,Lu Li,Yanxin Nan,Peng Li,Tao Deng,Zhipeng Lei,Yuanyuan Li,Jianhua Zhang
In this work, the effects of different sintering temperatures and TiO2concentrations on the dielectric properties of ZrO2and Nb2O5pre-doped CaCu3Ti4O12(CCTO) ceramics were investigated. These doped ceramics were sintered at temperatures of 1020, 1030, and 1040 °C, exhibiting the lowest dielectric loss of 0.01, which consistently remained below 0.03 across a wide frequency range from 10 to 105Hz. Simultaneously, they maintained a high dielectric constant of more than 3000 and remarkably met the requirements for an X8P capacitor (Δε′ ≤ ±10% at temperature range from −55 to 150 °C). It was clarified that TiO2doping increased grain boundary resistance, leading to the reduced dielectric loss, and elevated the grain boundary activation energy, thereby enhancing the temperature stability. The TiO2-doped CCTO-based ceramics also demonstrated reduced sensitivity to variations in sintering temperature, highlighting their excellent manufacturability. This characteristic holds great promise for the fabrication of CCTO-based ceramics, which usually exhibit poor repetitiveness.
研究领域:
材料科学
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电子工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Nanomaterials
·
2021
·Vol. 11
·期 6
·1531
·
IF 5.076
Haoxian Chen,Jiayi Wang,Yan Zhao,Qindan Zeng,Guofu Zhou,Mingliang Jin
The severe shuttle effect of soluble polysulfides hinders the development of lithium–sulfur batteries. Herein, we develop a three-dimensionally ordered macro/mesoporous (3DOM) Nb2O5/Nb4N5heterostructure, which combines the strong adsorption of Nb2O5and remarkable catalysis effect of Nb4N5by the promotion “adsorption-transformation” mechanism in sulfur reaction. Furthermore, the high electrocatalytic activity of Nb4N5facilitates ion/mass transfer during the charge/discharge process. As a result, cells with the S-Nb2O5/Nb4N5electrode delivered outstanding cycling stability and higher discharge capacity than its counterparts. Our work demonstrates a new routine for the multifunctional sulfur host design, which offers great potential for commercial high-performance lithium–sulfur batteries.Keywords:Nb2O5;Nb4N5;heterostructure;lithium-sulfur batteries
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2025
·
IF 4.8
Daguo Wu,Yong Liu,Xinghua Zhang,Jianguo Liu,Qi Zhang,Longlong Ma,Lungang Chen
The effective utilization of biomass is essential for addressing environmental challenges. The direct conversion of cellulose into chemicals and fuels is a key step in fostering a sustainable society. In this study, a mesoporous Pt-WO x /Nb 2 O 5 catalyst is synthesized and characterized using N 2 sorption, XRD, ICP, CO pulse, TEM, SEM, NH 3 -TPD, PY-IR, H 2 -TPR, and XPS. Under optimized catalyst preparation and reaction conditions, the yields of ethanol and propanol reach 50.3 % and 20.2 %, respectively. The mesoporous structure of Nb 2 O 5 , coupled with Pt, provides a rich balance of acidic and hydrogenation-active sites. Additionally, WO x plays a crucial role in the C C bond cleavage of cellulosic glucose and the C O bond cleavage of ethylene glycol, facilitating ethanol formation through Pt and the abundant Lewis acid sites from Nb 2 O 5 .
研究领域:
化学工程
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可再生资源
✓ 已验证
产品关联
DOI
高影响因子
Materials Research Express
·
2020
·Vol. 7
·期 11
·115502
·
IF 1.929
Jie Zhang,Dandan Li,Jianping Qiu,Zhengru Wen,Xiaohui Luo,Chaoqun Bian,Jian Chen,Mengfei Luo
Photocatalytic degradation of triclosan is one of the most promising way to eliminate triclosan pollution in water, yet it presents profound challenges to develop efficient photocatalysts to meet the demand of application. Herein, we demonstrate a facile hydrothermal-precipitation method to prepare amorphous Nb2O5 catalysts by using niobium(V) oxalate hydrate and ammonium carbonate. A series of amorphous Nb2O5 catalysts were obtained and analyzed by detail characterizations (XRD, XPS, BET and SEM). By optimizing synthesis conditions, it was found that 180/12-Nb2O5-(1:5) catalyst exhibited the optimal photocatalytic activity for triclosan degradation. Furthermore, the pseudo-first-order kinetic equations for triclosan degradation over 180/12-Nb2O5-(1:5) catalyst were investigated under conditions with different pH value. Among them, the triclosan degradation rate over 180/12-Nb2O5-(1:5) catalyst gave the highest reaction constant k (0.5 min−1) and shortest half-period (t1/2 = 0.17 min−1) at pH of 8. The presence of ionic state triclosan in base condition should be responsible for the improved degradation rate from acid to base reaction condition. Compared with molecular triclosan, ionic state triclosan exhibits very high reaction rate with radicals due to its strong electrophilic property. The high photocatalytic activity of 180/12-Nb2O5-(1:5) catalyst should be related to the presence of amorphous structure compared with calcined 180/12-Nb2O5-(1:5) catalyst with highly crystalline structure. The existence of N species doping and nano-sheet structure in catalyst is also thought to promote the catalytic reaction.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2015
·Vol. 3
·期 22
·11830-11837
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IF 7.443
Houlei Cui,Guilian Zhu,Yian Xie,Wei Zhao,Chongyin Yang,Tianquan Lin,Hui Gu,Fuqiang Huang
Black TiO2, with increased solar light absorption and enhanced photocatalytic and photoelectrochemical (PEC) performance, has attracted enormous attention, stimulating us to explore the blackening of other oxide semiconductors for enhanced properties. Here, we report the fabrication of black nanostructured Nb2O5 and its enhanced PEC properties for the first time. We successfully prepared oxygen-deficient black Nb2O5 nanochannels, which contain a considerable amount of oxygen vacancies (Nb4+ sites) serving as shallow donors. Black Nb2O5 exhibits strong visible and infrared light absorption, which can absorb 75.5% solar energy, which is superior to 5.7% for pristine Nb2O5. The PEC performance of black Nb2O5 photoanodes is significantly enhanced with a relatively large photocurrent of 1.02 mA cm−2 and a high applied bias photon-to-current efficiency (ABPE) of 0.345%, in comparison with the poor performance of pristine Nb2O5 (0.084 mA cm−2 photocurrent and 0.056% ABPE). These results indicate that black Nb2O5 is a promising material for PEC application and solar energy utilization.
研究领域:
材料科学
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能源科学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2017
·
IF 2.986
Fei Liang,Jiaxiang Liu
High density and low electrical resistivity ITO targets were prepared by normal pressure sintering in oxygen with Bi 2 O 3 –Nb 2 O 5 addition. The relative density, microstructure and electrical properties of the ITO targets can be adjusted by changing the sintering temperature (1350 °C~1550 °C) and the content of Bi 2 O 3 –Nb 2 O 5 . The results show that the sintering temperature of ITO targets with Bi 2 O 3 –Nb 2 O 5 decreased from 1550 °C to 1450 °C, and the maximum relative density (99.6%) and the lowest electrical resistivity (1.78×10 −4 Ω cm) were reached when the sintering temperature was 1450 °C with 5 wt% Bi 2 O 3 –Nb 2 O 5 . The carrier concentration increased as the increase of the contents of Bi 2 O 3 –Nb 2 O 5 and sintering temperature. The mobility first increased, and then decreased above 1450 °C as the sintering temperature increased.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
Scientific Reports
·
2015
·Vol. 5
·期 1
·1-9
·
IF 5.578
Liu Hui,Gao Nan,Liao Meiyong,Fang Xiaosheng
Ultraviolet (UV) photodetectors are important tools in the fields of optical imaging, environmental monitoring and air and water sterilization, as well as flame sensing and early rocket plume detection. Herein, hexagonal-like Nb 2 O 5 nanoplates are synthesized using a facile solvothermal method. UV photodetectors based on single Nb 2 O 5 nanoplates are constructed and the optoelectronic properties have been probed. The photodetectors show remarkable sensitivity with a high external quantum efficiency (EQE) of 9617% and adequate wavelength selectivity with respect to UV-A light. In addition, the photodetectors exhibit robust stability and strong dependence of photocurrent on light intensity. Also, a low-cost drop-casting method is used to fabricate photodetectors based on Nb 2 O 5 nanoplate film, which exhibit singular thermal stability. Moreover, the hexagonal-like Nb 2 O 5 nanoplates show significantly better photocatalytic performances in decomposing Methylene-blue and Rhdamine B dyes than commercial Nb 2 O 5 .
研究领域:
材料科学
·
光学工程
·
环境科学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Wei Li,Xiang Xia,Jiangtao Zeng,Liaoying Zheng,Guorong Li
NaNbO 3 (NN)-based solid solutions show potential applications in energy storage capacitors, strain actuators, and electrocaloric cooling devices. However, NN ceramics with distinct structures, which are prepared using various Nb 2 O 5 precursors, have not been studied. In this work, two types of Nb 2 O 5 precursors were used, including coexisting orthorhombic and monoclinic phases (denoted as OM), and single orthorhombic phase (denoted as O). Phase structure, grain morphology, sintering characteristics, ferroelectric performance, dielectric properties , and thermal-expansion properties were systematically investigated. Rietveld refinement of XRD data revealed that synthesized and sintered samples showed different phase structures. The content of ferroelectric phase (Q phase, space group P2 1 ma) was 82.7% in synthesized NN-OM, whereas it was only 73.2% in synthesized NN-O; it was 33.8% in sintered NN-OM, while it was 18.6% in sintered NN-O. Raman spectra verified that the Q phase in NN-OM was more than that in NN-O. Curie temperature ( T c ) of NN-OM was 363 °C, whereas T c of NN-O was only 352 °C. Furthermore, compared with NN-O, NN-OM showed an inhomogeneous grain size distribution, lower optimum sintering temperature , higher phase transition temperature, stronger ferroelectric performance, and larger thermal-expansion displacement. Therefore, crystal structure of Nb 2 O 5 has a great influence on the structure and performances of NN ceramics.
研究领域:
材料科学
·
无机化学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2024
·
IF 20.2
Tianjiao Wu,Bibo Ma,Huanhuan Bai,Lin Wang,Yumei Zhang,Qingzhi Luo,Jing An,Huiying Mu,Desong Wang,Yandong Duan
Developing highly efficient photocatalysts that selectively convert NO pollutants to NO 3 ¯ while storing metabolic nitrogen for crops remains a great challenge. Simultaneously, there is a dearth of research investigating the relationship between the chemical environment and the activity of catalytic sites. Herein, an efficient impregnation approach to access atomically dispersed Sr single atoms supported on Nb 2 O 5 is reported; meanwhile, various ligands (-Cl, -Br, -OH) are employed to customize the local structure. The results show that Cl-Sr/Nb 2 O 5 exhibits excellent catalytic performance in eliminating NO, which is significantly superior to other catalysts. The introduction of Sr atom and ligand increases the energy barrier of NO 2 formation, thus improving the selectivity of converting NO to NO 3 ¯. This study highlights the importance of precisely designing the catalytic site at the atomic level, and the obtained insights may serve as a valuable guide for developing future catalyst designs.
研究领域:
环境科学
·
材料科学
✓ 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）