Molecular Catalysis
·
2021
·
IF 5.062
Yue Zhang,Zhiyong Pan,Nan Wang,Li Wang
Silica SBA-15 without removal of template P123 was calcined in an inert atmosphere and the carbon-modified SBA-15 thus obtained was used as the support of Pd catalyst for the hydrogenation of 2-ethylanthraquinone (EAQ). The effects of extraction times of P123 in SBA-15 with water prior to inert calcination and calcination temperature on the structure and catalytic performance of Pd catalyst were studied. The results of elemental analysis, X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma, Fourier transform infrared spectroscopy, Raman spectra, water contact angle measurement, N 2 adsorption-desorption, transmission electron microscopy and energy dispersive X-ray mapping showed that carbon content of catalysts varied in the range of 3.4 % and 1.1 % with increasing extraction times from 0 to 6 due to the decrease in the residual amount of P123 in uncalcined SBA-15. With rising calcination temperature, the occurrence state of carbon in catalysts was converted from amorphism into graphite. The Pd catalyst supported on SBA-15 extracted for 3 times and calcined at 650 °C had 2.0 % carbon, and exhibited the highest activity (0.37 molH 2 ·gPd −1 ·min −1 ) and selectivity (98.9 %). This is due to the presence of appropriate amount of carbon, which provided a relatively high hydrophobicity without significantly reducing the specific surface area and pore size of SBA-15 support. The high hydrophobicity benefits the adsorption of EAQ from the working solution to the surface of catalyst.
研究领域:
催化化学
·
材料科学
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产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Yashan Huo,Yujia Tan,Fuchun Zhang,Wei Cui,Yixuan Wang,Zhihui He
It is anticipated that the advancement of efficient wave-absorbing materials across diverse frequency bands can meet the demands of covert communication and reduced radar detection, in particular, in the context of active camouflage in the era of electronic information warfare. In this study, a carbon-modified nickel ferrite (NiFe 2 O 4 ) hybrid fiber was successfully synthesized via electrostatic spinning and in-situ carbothermal reduction . The carbothermal reduction temperature can be used to adjust the carbon content of NiFe 2 O 4 /C hybrid nanofiber , thereby enabling the tuning of the conductance loss. Furthermore, the effective wave-absorption frequency range can be finely adjusted from the Ku-band to the C-band. This is attributed to a deliberate tailoring, which enables the achievement of synergistic and complementary effects of the magnetic and dielectric properties , influencing the impedance matching level of each NiFe 2 O 4 /C hybrid absorber. A large electromagnetic loss indicates a high-efficiency energy conversion, and thus, the excellent microwave absorption properties indicate that this material exhibits promising potential for integration into multifunctional micro–nano electromagnetic devices and weaponry.
研究领域:
材料科学
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电磁学
✓ 已验证
产品关联
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
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
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IF 3.83
Qian Dai,Bingnan Yuan,Minghui Guo,Kun Zhang,Xueqi Chen,Zihui Song,Tat Thang Nguyen,Xiaojing Wang,Shudong Lin,Jincheng Fan,Yingchun Li,Hu Liu,Zhanhu Guo
To improve the photocatalytic efficiency of niobium pentoxide (Nb 2 O 5 ) for the degradation of organic pollutants, a novel nano-fibriform C-modified Nb 2 O 5 (F–C/Nb 2 O 5 ) photocatalyst was successfully synthesized by niobium oxalate as precursor and nanofibrillated cellulose (NFC) as template and carbon source. Vacuum induced self-assembly method was used to form the nano-fibriform morphology. Compared to ordinary C/Nb 2 O 5 and commercial Nb 2 O 5 , F–C/Nb 2 O 5 exhibited a typical three-dimensional nanorod structure with plenty of pores. The specific surface area of F–C/Nb 2 O 5 was 3 times that of C/Nb 2 O 5 . The prepared F–C/Nb 2 O 5 exhibited a 3.01 eV bandgap and was able to be activated under visible light while that was unable for commercial Nb 2 O 5 with 3.19 eV bandgap. The F–C/Nb 2 O 5 showed the best photocatalytic efficiency in pH value ≤ 3. After cycling for 5 times, the photocatalytic efficiency of F–C/Nb 2 O 5 was still 2.4 times of the ordinary C/Nb 2 O 5 under visible light. Meanwhile, the self-assembly mechanism and photodegradation mechanism were proposed. This study provides a new strategy to form a special nano-fibriform C-modified niobium pentoxide with extremely high photocatalytic efficiency in aqueous solutions.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
NANOTECHNOLOGY
·
2021
·Vol. 32
·期 49
·495603
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IF 3.874
Peiyuan Ji,Jing Wan,Junlin Lu,Dazhi Zhang,Chenguo Hu,Yi Xi
The development of simple preparation and excellent capacity performance electrode materials is the key to energy conversion and storage for supercapacitors. Based on the growth mechanism of crystal, Zn induced NiCo nanosheets and nanoneedles composite structure deposed on Ni foam (ZNC) are successfully attained by a facile one-step method, the growth mechanism of the composite structure is further discussed. Because of its unique composites structure and additional modification of carbon, the carbon modified ZNC (ZNC@C) delivers better energy storage ability (2280 mC cm−2 at 2 mA cm−2) compare to ZNC. An asymmetric supercapacitor (ASC) is assembled by ZNC@C as the positive electrode and carbonized popcorn as the negative electrode. The ASC exhibits good energy storage performance. Zn also positively affects the adsorption energy to enhance the capacitance property based on Density Functional theory calculation. The simple method for the composite structure by tuning the kinetics behaver of the crystal can provide a new strategy in synthesizing the materials, and the material with a unique structure and high performance will have potential applications in the field of energy storage.
研究领域:
材料科学
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能源存储与转换
✓ 已验证
DOI
高影响因子
JOURNAL OF POWER SOURCES
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2016
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IF 6.333
Junhua Hu,Lijie Wang,Peng Zhang,Changhao Liang,Guosheng Shao
Carbon-layer-coated TiO 2 /WO 3 nanofibers (WTC) were fabricated by combining the electrospinning technique (for TiO 2 /WO 3 nanofibers) and hydrothermal method (for carbon shell). The structure characterization results showed that TiO 2 /WO 3 nanofibers (WT) were encased within an uniform carbon shell about 10 nm in thickness. By adjusting the content of WO 3 , the graphitization degree of carbon layer could be controlled, and the WTC nanofibers had remarkable light absorption in the visible region. Furthermore, the photoelectrochemical performance and photocatalytic activity were investigated systematically. As expected, the H 2 -generation rate of the as-prepared composite materials was greatly enhanced compared with pure TiO 2 nanofibers (TNFs), TiO 2 /WO 3 nanofibers (WT) and TiO 2 @carbon core/shell nanofibers (TC). The enhanced activities were mainly attributed to the multichannel-improved charge-carrier photosynthetic heterojunction system with the carbon layer on the surface of TiO 2 as an electron collector and WO 3 as a hole collector, leading to effective charge separation on these components, which were evidenced by photoluminescence spectroscopy (PL), electrochemical impedance spectroscopy (EIS) and photocurrent analysis. Besides, the addition of WO 3 promoted the graphitization of carbon layer, which in turn improved transport of electrons in the carbon layer and also contributed to the performance improvement.
研究领域:
材料科学
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能源科学
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环境科学
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Hongjin Xue,Yingqiang Wu,Zhaomin Wang,Yabin Shen,Qujiang Sun,Gang Liu,Dongming Yin,Limin Wang,Qian Li,Jun Ming
Metal–organic framework (MOF)-derived materials are attracting considerable attention because of the moldability in compositions and structures, enabling greater performances in diverse applications. However, the nanostructural control of multicomponent MOF-based complexes remains challenging due to the complexity of reaction mechanisms. Herein, we present a surface-induced self-nucleation-growth mechanism for the zeolitic imidazolate framework (ZIF) to prepare a new type of ZIF-8@SiO2 polyhedral nanoparticles. We discover that the Zn hydroxide moieties (Zn–OH) within ZIF-8 can trigger the hydrolysis of tetraethyl orthosilicate effectively on the ZIF-8 surface precisely, avoiding the formation of free orthosilicic acid (Si(OH)4) successfully. This is a pioneering work to elucidate the importance of MOF surface properties for preparing multicomponent materials. Then, a novel well-dispersed silicon hollow nanocage (H–Si@C) modified by the carbon was prepared after removal of the ZIF-8 and magnesiothermic reduction. The as-prepared H–Si@C demonstrates an overwhelmingly high lithium storage capability and extraordinary stability in lithium-ion batteries (LIBs), particularly the impressive performances when it was matched with the LiNi0.6Co0.2Mn0.2O2 cathode in a full cell. The MOF surface-induced self-nucleation-growth strategy is useful for preparing more multifunctional materials, while the study of lithium storage performances of the H–Si@C material is practical for LIB applications.
研究领域:
材料科学
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电化学
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Xiaohong Guan,Xueying Du,Meichuan Liu,Hejie Qin,Junlian Qiao,Yuankui Sun
Given that there are still some debates on the influence of carbon modification on zerovalent iron (ZVI) decontamination process, the roles of carbon on trichloroethylene (TCE) reduction by ZVI were re-investigated in this work. Compared to activated carbons (AC) with high adsorption ability, carbon fibers (CF) with good electronic conductivity performed much better in enhancing ZVI performance in terms of both reactivity and selectivity. Moreover, it was interesting to observe that a low carbon loading is sufficient to effectively improve TCE reduction and this promoting effect would decline with further increasing the carbon amounts from 1.0 wt.% to 50 wt.%. Regarding to the ZVI selectivity, a relatively high carbon loading (especially for CF, it may be as high as 50 wt.%) was needed to protect ZVI from non-productive reactions with H 2 O/H + effectively. However, a mixture of 10 wt.% AC and 1.0 wt.% CF could combine their respective merits of inhibiting side reactions and enhancing TCE reduction, and thus simultaneously enhanced the reactivity and selectivity of ZVI. Mechanistic investigations revealed that carbon modification could enhance the ZVI performance through improving TCE adsorption and/or accelerating electron transfer, while the latter one may play a more important role especially at high carbon loadings.
研究领域:
环境科学
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化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
Surfaces and Interfaces
·
2025
·
IF 6.3
Ling Zhang,Weijie Cai,Hongjuan Duan,Shaowei Zhang,Haijun Zhang
To improve the wettability and dispersion of graphite flakes in aqueous solvents without introducing impurities that could contaminate the graphite, the carbon-coated graphite flake (CGF) composite powders were fabricated using chitosan as a raw material by one-step hydrothermal carbonization. The effects of different types of saccharides (glucose, starch and chitosan), graphite/chitosan mass ratio, solution pH, amount of polyvinyl pyrrolidone (PVP), hydrothermal period and hydrothermal temperature on the preparation of CGF were investigated. The hydrothermal temperature of 190°C, hydrothermal period of 12h, dispersion pH of 7, graphite/chitosan mass ratio of 4 and PVP addition of 2 wt% were the most optimal preparation condition for the hydrothermal preparation of CGF. The water contact angle (WCA) of the prepared CGF was rapidly reduced from 49.1° to nearly 0° in about 1.2 s, exhibiting a superhydrophilicity. This behavior is attributed to the introduction of hydrophilic functional groups, and the absence of introduced impurities ensures that they can be used in applications requiring high purity graphite. Moreover, the bond between the carbon coating and the graphite was strong enough that it did not detach after 10 min of agitation in water. Thus, hydrothermal carbonized coatings prepared using chitosan as a raw material has great potential for improving the wettability and dispersion of graphite flakes in aqueous solvents. This approach provides an effective strategy for producing superhydrophilic graphite flakes without introducing impurities, thus expanding their potential use in more advanced high-tech applications.
研究领域:
材料科学
·
表面化学
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纳米技术
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2024
·
IF 8.1
Jing Li,Zhengguang Shi,Qianru Lin,Yaohui Zhang,Mingxue Huo,You Wang,Hsu-Sheng Tsai
VSe 2 is a promising anode material for Li-ion batteries (LIBs) due to its unique layered structure, and its metallic properties. However, further exploration to investigate the lithium storage performance of VSe 2 is limited by the synthesis difficulty of pure VSe 2 . In this work, a novel nitrogen-doped carbon modified VSe 2 obtained by using p -phenylenediamine as the reducing agent is reported. This material delivers a reversible capacity of 738.25 mA h g −1 at 100 mA g −1 and after 50 cycles, it retains 772.15 mA h g −1 . Using p -phenylenediamine as a reducing agent to obtain VSe 2 is demonstrated for the first time, and p -phenylenediamine also provides carbon and nitrogen sources for the heteroatom modification of VSe 2 . This modification of nitrogen-doped carbon facilitates the generation of new active sites, and improve charge transfer. First-principle calculations show that the diffusion barrier for the Li + migration within the VSe 2 layers is low. The ex-situ X-ray diffraction (XRD) results verify that VSe 2 stores lithium through intercalation and conversion reactions. This work may provide a new solution for synthesizing high-performance transition metal dichalcogenide electrode materials.
研究领域:
材料科学
·
电化学
·
纳米材料
·
能源存储
·
计算材料学
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无机合成
·
电池技术
✓ 已验证
DOI
高影响因子
Journal of Energy Storage
·
2023
·
IF 9.4
Tianli Zhang,Mengrong Wu,Hui Gu,Haiwei Yu,Ming Zhou,Xingmei Guo,Yuanjun Liu,Xiangjun Zheng,Qinghong Kong,Junhao Zhang
To address the challenges associated with significant volume expansion and limited electronic conductivity of transition metal sulfides (TMSs) as anode materials in lithium-ion batteries. Nitrogen doped carbon (NC) and carbon nanotubes (CNTs) modified CoS 2 /NiS 2 (Co-Ni-S/NC/CNTs) composites were prepared by a simple chemical precipitation method and sulfurization reaction. Co-Ni-S/NC/CNTs composites have special structure, utilizing NC as carrier and CNTs as cladding layer . When evaluated as anode materials for lithium-ion batteries, the initial discharge specific capacity of Co-Ni-S/NC/CNTs anode delivers 1518.8 mAh g −1 at 0.1 A g −1 , and a high reversible capacity of 1137 mAh g −1 is kept after 100 cycles, which is higher than the discharge specific capacity (1117.1 mAh g −1 ) of the second cycle. At a current density of 0.5 A g −1 , a capacity of 468 mAh g −1 is maintained after 300 cycles. The excellent cycling stability of the CoS 2 /NiS 2 anode can be primarily attributed to that CNTs layer can enhance the conductivity of CoS 2 /NiS 2 , and the incorporation of NC can effectively improve the infiltration of electrolytes. Meanwhile, the synergistic action of CNTs and NC can mitigate the volume expansion during charging and discharging processes.
研究领域:
材料科学
·
电化学
·
能源存储
✓ 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）