SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Peng Zhang,Cheng Peng,Hui Li,Jing Huang,Yan Wang,Youqing Yu,Shimin Ding,Songli Liu,Yanchun Zhao
Reactive species, such as hydroxyl radicals (·OH), holes (h + ) and superoxide radicals (·O 2 − ), are considered as the main active substances involved in the photocatalytic degradation of organic pollutants. However, to the best of our knowledge, the effect of the photon energy on the generation of these species has never been examined in detail. In this study, the photocatalytic production of ·OH, h + and ·O 2 − over niobium pentoxide (Nb 2 O 5 ) was investigated as a function of the excitation wavelength. The ESR results clearly show that all three active species can be generated at 355 nm for both pure and C-doped Nb 2 O 5 . At 532 nm, which is well beyond the absorption edge of Nb 2 O 5 (399 nm), only h + and •O 2 − are produced over pure Nb 2 O 5 , while at the same time all three species can be produced over C-doped Nb 2 O 5 . The results of the trapping experiments indicate that •O 2 − and h + are the main reactive species that are responsible for the photocatalytic degradation. The photogenerated holes play a crucial role in the wavelength range of 365–420 nm but become less active with increasing wavelength. •O 2 − shows little dependence on wavelength and is consistently active at all wavelengths between 365 and 630 nm, in particular, for C-doped Nb 2 O 5 . It is concluded that the presence of localized states within the forbidden gap has a profound impact on the photocatalytic activity in the visible-wavelength region.
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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.
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高影响因子
Materials
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2024
·Vol. 17
·期 20
·4991
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IF 3.1
Wenjun Lei,Xinxin Zhao,Chao Liang,Huai Wang,Xuehong Li,Mingkun Jiang,Xiaofeng Li,Fengqin He,Yonghui Sun,Gang Lu,Hairui Cai
Developing an OER electrocatalyst that balances high performance with low cost is crucial for widely adopting PEM water electrolyzers. Ru-based catalysts are gaining attention for their cost-effectiveness and high activity, positioning them as promising alternatives to Ir-based catalysts. However, Ru-based catalysts can be prone to oxidation at high potentials, compromising their durability. In this study, we utilize a simple synthesis method to synthesize a SnO2, Nb2O5, and RuO2composite catalyst (SnO2/Nb2O5@RuO2) with multiple interfaces and abundant oxygen vacancies. The large surface area and numerous active sites of the SnO2/Nb2O5@RuO2catalyst lead to outstanding acidic oxygen evolution reaction (OER) performance, achieving current densities of 10, 50, and 200 mA cm−2at ultralow overpotentials of 287, 359, and 534 mV, respectively, significantly surpassing commercial IrO2. Moreover, incorporating Nb2O5into the SnO2/Nb2O5@RuO2alters the electronic structure at the interfaces and generates a high density of oxygen vacancies, markedly enhancing durability. Consequently, the membrane electrode composed of SnO2/Nb2O5@RuO2and commercial Pt/C demonstrated stable operation in the PEM cell for 25 days at an industrial current density of 1 A cm−2. This research presents a convenient approach for developing a highly efficient and durable Ru-based electrocatalyst, underscoring its potential for proton exchange membrane water electrolysis.
研究领域:
材料科学
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电化学
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DOI
PubMed
高影响因子
JOURNAL OF POWER SOURCES
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2024
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IF 8.1
Xuxu Wang,Ruxiu He,Ying Bai,Fen Yao,Shuang Gao,Ping Nie,Limin Chang
T-Nb 2 O 5 is a promising anode material for high power density lithium-ion batteries (LIBs) due to its fast lithium storage capacity and safe lithiation potential. However, its practical application is hindered by its low electronic conductivity. In this work, we improved the electrochemical performance of T-Nb 2 O 5 by surface P-doping and the N-doped carbon substrate. Surface P-doping guided by defects enhances the electronic conductivity of the material, which can synergize with N-doped carbon substrates to form a conductive network and accelerate the lithiation/delithiation process. More importantly, surface P-doping does not destroy the internal crystal structure of the material, ensuring the stability of the Nb 2 O 5 during the charge/discharge process. When used as the anode for LIBs, the Nb 2 O 5 -P/N-C exhibits great cycling stability and high-current charge/discharge performance. The specific capacity of Nb 2 O 5 -P/N-C exceeds 116 mAh g −1 after 1000 cycles at 1000 mA g −1 . This work presents a novel approach to improve the electrochemical performance of T-Nb 2 O 5 .
研究领域:
材料科学
·
能源存储
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DOI
高影响因子
ENERGY & FUELS
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2024
·
IF 5.2
Xin Zhang,Zaiman Zhang,Hao Li
The aqueous hydrodeoxygenation (HDO) of renewable biomass is an effective method to produce alternative fuels and high-value-added chemicals. Nonetheless, metal leaching and support collapse are the main obstacles in aqueous HDO. Herein, a series of Ni/T-Nb2O5@C catalysts were successfully prepared for selective HDO of vanillin (a typical lignin-derived model compound). Characterization results revealed that the superior catalytic performance of Ni/T-Nb2O5@C catalysts was due to the efficient adsorption of the reactant preferentially via oxygen vacancies and the excellent selection of deoxygenated products via acid sites on the catalyst surface. Meanwhile, water can interact with vanillyl alcohol (VA) through hydrogen bonding to form a more stable transition state, further reducing the activation energy of the VA hydrogenolysis process and promoting the conversion of VA to 2-methoxy-4-methylphenol (MMP). Ni/T-Nb2O5@C2-2 catalyst exhibited excellent performance for vanillin HDO, achieving 99.9% conversion, 96.6% MMP selectivity, and 87.7% mass yield at 150 °C for 1 h, 1 MPa H2, and a water:ethanol ratio of 8:12, which greatly improved the MMP selectivity (79.2%) of unmodified Ni/T-Nb2O5 catalyst. Moreover, the catalyst had good catalytic capability after eight cycles of less than 25% conversion, and the retention of the initial active substance during the reaction was analyzed. This work may provide insights into the rational design of composite-supported catalysts for biomass-derived compounds HDO in the aqueous phase.
研究领域:
催化化学
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生物质能
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材料科学
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2022
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IF 6.371
Wanxing Zhang,Pengcheng Mao,Yuhang Jin,Hai Ming,Zhipeng Li,Danfeng He,Hongyu Sun,Yanlong Yu,Yanguo Liu
Niobium pentoxide (Nb 2 O 5 ) anodes have attracted much attention as a candidate for the next generation lithium-ion batteries (LIBs) due to the unique physical and chemical properties. However, some critical issues, like low electronic conductivity, inefficient ionic diffusion, must be addressed before practical applications. In this work, we employed a facile NaBH 4 engaged chemical reduction method to modify Nb 2 O 5 anodes. Microstructure and surface chemistry analysis indicated that the Nb 2 O 5 materials have micro/nanoscale three-dimensionally interconnected morphology, and contain three different phases (T-, M-, and H-Nb 2 O 5 ). More importantly, oxygen vacancies are introduced by the NaBH 4 reduction treatment, and the oxygen vacancy amount can be modulated by changing the NaBH 4 concentration. As anodes for LIBs, the optimized sample exhibited a reversible capacity of 252.2 mAh·g −1 after 100 cycles at a current density of 1 C, and a reversible capacity of 139.4 mAh·g −1 at a large current density of 10 C. The electrochemical performance enhancement can be attributed to the combination of multiscale structural design, i.e., oxygen vacancy, nanoscale phase interface , and micro/nanoscale three-dimension assembly. We expect the present synergistic strategy can be employed to manipulate the key structures in different functional materials for broader applications.
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
CHEMICAL ENGINEERING JOURNAL
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2026
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IF 12.5
Qi Lai,Yu Dou,Qing Zhang,Yunhai Zhu,Yingkui Yang
Orthorhombic Nb 2 O 5 (T-Nb 2 O 5 ) has emerged as a promising fast-charging anode due to its open framework structure, safe potential and intercalation pseudocapacitance characteristic. However, its practical application is hindered by the low electronic conductivity. Herein, a synergistic nano-amorphization engineering strategy was employed to fabricate crystalline-amorphous core-shell T-Nb 2 O 5 (C/A-T-Nb 2 O 5 ) nanofibers via electrospinning technology. The obtained carbon-free, chain-like C/A-T-Nb 2 O 5 nanofibers formed via interconnected Nb 2 O 5 nanoparticles enables rapid kinetics and excellent structural stability without compromising the energy density. The chemical etching creates an amorphous shell on single-crystalline core, which establishes a built-in electric field (BIEF) at the interface. In-situ characterizations with theoretical simulations suggest that BIEF effectively drives electrons from amorphous shell to the inner reaction sites and lowers Li-ions diffusion barrier. The amorphous shell with oxygen vacancies boosts Li-ions/electron transport, simultaneously alleviating lattice stress during cycling. Consequently, C/A-T-Nb 2 O 5 delivers a superior rate capability of 102 mAh g −1 at 50C and exceptional durability, retaining 69.5% capacity after 2000 cycles at 10C. A full pouch cell paired with C/A-T-Nb 2 O 5 anode and NCM811 cathode further demonstrates the practical viability. This integrated architectural modulation and amorphization engineering strategy establish a new paradigm for designing kinetically balanced electrodes for high-power batteries.
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高影响因子
SOLAR ENERGY
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2017
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IF 4.018
Liang Chu,Wei Liu,Aiai Yu,Zhengfei Qin,Ruiyuan Hu,Huazhong Shu,Qiu-Ping Luo,Yonggang Min,Jianping Yang,Xing'ao Li
TiO 2 modification via TiCl 4 treatment has been widely used to improve the power conversion efficiency (PCE) of dye-sensitized solar cells (DSSCs), in which the effects usually attribute to the inhibition of charge recombination by barrier effect. Niobium pentoxide (Nb 2 O 5 ) is considered a promising photoelectrode material for DSSCs. Here we prepared urchin-like orthorhombic Nb 2 O 5 nanospheres consisting of ultrathin nanorods by a hydrothermal method , which were further developed as photoelectrodes for DSSCs. The TiO 2 modification on the urchin-like orthorhombic Nb 2 O 5 nanospheres increases the photocurrent and PCE of the DSSCs. However, the impedance spectroscopy showed that charge recombination was not reduced by the TiO 2 modification. The improvement in the photocurrent and PCE has been attributed to the enhanced absorption of dye molecules (N719). The results indicate that the enhancement of dye absorption for orthorhombic Nb 2 O 5 photoelectrodes is the desirable approach to improve the performance of orthorhombic Nb 2 O 5 -based DSSCs.
研究领域:
材料科学
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能源科学
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高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Dongsheng Jiang,Yuzhe Li,Chao Zhang,Ruifang Wang,Jinpeng Zhu,Wen Chen,Yusi Che,Jilin He
Bayan Obo tailings are rich in niobium and other valuable elements; however, the phase evolution of niobium-bearing slag within these tailings remains poorly understood. This knowledge gap significantly impedes comprehensive utilization of these strategic resources. In this study, a CaO-SiO 2 -Nb 2 O 5 -5%Na 2 O-5%Al 2 O 3 -3%CaF 2 slag system was investigated to examine the phase equilibrium types, compositional characteristics, and distributional evolution under varying w (CaO)/ w (SiO 2 ) ratios and w (Nb 2 O 5 ) contents, using high-temperature equilibrium experiments. Following a 24-hour high-temperature equilibrium treatment at 1473 K under an argon atmosphere, a range of compounds including 13CaO·8SiO 2 ·Nb 2 O 5 ·CaF 2 , 2CaO·4SiO 2 ·Na 2 O·Al 2 O 3 , CaO·Nb 2 O 5 ·NaF, 2CaO·Nb 2 O 5 , and CaO·SiO 2 were identified. An increase in Nb 2 O 5 content coupled with a reduction in the w (CaO)/ w (SiO 2 ) ratio favored the formation of CaO·Nb 2 O 5 ·NaF (pyrochlore phase) and 2CaO·Nb 2 O 5 . These two phases exhibited high Nb concentrations, with the CaO·Nb 2 O 5 ·NaF (pyrochlore) phase containing up to approximately 70% Nb. The optimal smelting conditions for niobium enrichment in the pyrochlore phase were identified within the range of w (CaO)/ w (SiO 2 ) = 0.74∼0.80 and w (Nb 2 O 5 ) = 13.61%∼16.11%.
研究领域:
冶金学
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材料科学
·
矿物加工
·
物理化学
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2021
·
IF 19.503
Wenkang Xu,Xiaoyao Li,Chao Peng,Guangxing Yang,Yonghai Cao,Hongjuan Wang,Feng Peng,Hao Yu
MXenes, 2D transition metal carbides/nitrides, have been demonstrated as promising platform for fabricating novel composites with interesting photo-/electrochemical properties. It is desirable to gain insights into the reactivity of MXenes, enabling the controllable transformation of MXenes. Here, a one-pot hydrothermal synthesis method of MXene-based photocatalyst is validated by harnessing the reducibility of Nb 2 CT x MXene . The origin of reducibility of Nb 2 CT x during the hydrothermal oxidation process was demonstrated as the active hydrogen produced from the water splitting in the presence of Nb 2 CT x , which reduced Ru 3+ in situ to Ru nanoparticles on Nb 2 O 5 nanowires derived from Nb 2 CT x . Compared with the traditional photo-deposition method, the chemical valance of the noble metal Ru/Pt obtained by the one-pot synthesis method was closer to the metal state, which reduced the charge transfer resistance by 82.5%. It led to the photocatalytic hydrogen production of 10.11 mmol·h −1 ·g −1 with 41.25% apparent quantum yield at 313 nm.
研究领域:
材料科学
·
光催化
·
能量转换
·
纳米材料
·
氢气生产
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DOI
高影响因子
MATERIALS & DESIGN
·
2017
·
IF 4.364
Puhong Wen,Lili Ai,Taotao Liu,Dengwei Hu,Fangyi Yao
The regular orthorhombic Nb 2 O 5 (O-Nb 2 O 5 ) rectangle nanosheets dominantly exposed (010) facet are synthesized by a hydrothermal topological reaction with a precursor of K 4 Nb 6 O 17 ·4.5H 2 O (KNbO). The structure and morphology of the samples obtained at different temperatures and pH values of reacting solution are investigated. The results suggest that there are two topological reactions in this process. One is the acid-exchanging reaction transforming into H 4 Nb 6 O 17 ·3H 2 O (HNbO) nanosheets from KNbO rectangle nanosheets , and the other is dehydration reaction transforming into O-Nb 2 O 5 rectangle nanosheets from HNbO nanosheets. And the {010} facets of O-Nb 2 O 5 crystal are transformed from the {010} facets of HNbO crystal in the ingenious topological reaction. The photoelectric performance of the obtained O-Nb 2 O 5 nanosheets is evaluated by decomposing water to H 2 under 370 nm UV light illumination and measuring the accompanying photocurrent . The photocurrent density is 680 nA·cm − 2 generated by splitting water with O-Nb 2 O 5 nanosheets as photocatalyst , and it is 4.3 times of the contrast sample. The result indicates that the (010) facet of O-Nb 2 O 5 is one of the highest photocatalytic active surfaces and shows high photoelectric conversion efficiency. Thus, the O-Nb 2 O 5 nanosheets dominantly exposed (010) facet have potential applications in photocatalyst and photoelectric nanodevices .
研究领域:
材料科学
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光催化
·
纳米材料
·
无机化学
·
能源材料
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DOI
高影响因子
DESALINATION
·
2026
·
IF 9.9
Markos Medhin Ashebo,Zixiao Xu,Haolan Shi,Huancheng Dong,Ningning Liu,Fei Yu,Jie Ma
1D Nb 2 O 5 nanorods grown in situ uniformly on the surface 2D Nb 2 C MXene. • Nb 2 O 5 nanorods act as passivation layers, mitigating MXene restacking and oxidation. • Interfacial charge transfer between Nb 2 O 5 and Nb 2 C accelerates electron kinetics. • The Nb 2 O 5 -Nb 2 C hybrid exhibits excellent desalination performance and cycling stability. Self-stacking and oxidative instability limit the ion accessibility and cycling stability of MXene electrodes in capacitive deionization (CDI). To address these limitations, a controlled partial derivation strategy was used to construct Nb 2 O 5 nanorods on Nb 2 CT x MXene nanosheets, forming 1D Nb 2 O 5 nanorod/2D Nb 2 C heterostructure. The derived Nb 2 O 5 nanorods increased the accessible surface area, provided expanded ion intercalation channels, suppressed Nb 2 CT x restacking, and also acted as a partial passivation layer to inhibit further MXene oxidation. Electrochemical measurements showed that the Nb 2 O 5 -Nb 2 C electrode exhibited higher capacitance and lower charge-transfer resistance than pristine Nb 2 C, suggesting improved interfacial charge transfer behavior and ion storage kinetics. The Nb 2 O 5 -Nb 2 C hybrid delivered a salt adsorption capacity (SAC) of 51.2 mg g −1 at 1.6 V, an average salt removal rate (SAR) of 1.7 mg g −1 min −1 , and retained 90.5% of its initial capacity after 200 cycles. These results indicate that controlled partial oxidation can not only mitigates the instability of Nb 2 C, but also improves ion accessibility, electrochemical kinetics, and cycling durability of Nb-based MXene electrodes for CDI. Download: Download high-res image (360KB) Download: Download full-size image
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高影响因子
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