ENERGY & FUELS
·
2022
·
IF 4.654
Xiaohan Wang,Zhiqing Yu,Jinxiao Sun,Qiang Wei,Haoran Liu,Wenbin Huang,Luyuan Zhao,Meng Si,Yasong Zhou
A series of in situ dodecyl trimethyl ammonium bromide (DTAB)-modified small-crystal Y zeolites have been successfully synthesized by DTAB addition to the seed synthesis procedure, which was used to create the small crystal size Y zeolites. Compared to the Y zeolites prepared without DTAB, the Y zeolites prepared with DTAB have a uniform morphology and mesoporous structure, a larger specific surface area (up to 32.3 m2 g–1 increase), a smaller crystal size (up to 66 nm reduction), and more Brönsted acid sites (up to 55 μmol/g increase). After loading with NiW, the corresponding NiW catalysts were utilized in the hydrocracking of n-hexadecane. It is evident from the catalytic performance that the catalysts containing DTAB-modified small-crystal zeolites have a higher yield and selectivity of primary cracking products compared with the Y zeolites without DTAB modification. Moreover, the conversion of n-hexadecane is also higher due to its low mass-transfer resistance, high dispersion, and sulfation of W species. When the molar ratio of DTAB/Al2O3 is 0.15, the corresponding catalyst has the optimum balance between cracking and hydro–dehydrogenation activity. Therefore, it has the most excellent catalytic performance and a 7.3% increase in C8–C12 yield.
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高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2021
·
IF 7.46
Xu Tian,Lijia Yao,Xiuxiu Cui,Rongjun Zhao,Xuechun Xiao,Yude Wang
Fast and effective detection of harmful gases is crucial criterion for the current development of gas sensors. In this paper, a novel n-butanol gas sensor using Al-doped CdIn 2 O 4 nanofibers (ACO NFs) is synthesized by an electrospinning method . The different morphologies of the as-prepared ACO NFs are controlled by doping different Al contents . Systematic characterizations demonstrate that the doping of Al to CdIn 2 O 4 NFs would enhance the reaction activities between the gas and sensing materials, such as generating large amounts of adsorbed oxygen and improving the specific surface area of sensing materials. The results show that the detection limit of all prepared sensors for n-butanol is sub-ppm, and less than 250 ppb. The optimal Al-doped CdIn 2 O 4 (5.0% Al/Cd molar ratio) based gas sensor results in 3.32-fold enhancement in gas response to 200 ppm n-butanol at an operating temperature of 300 °C and exhibits excellent long-term stability compared with the pure CdIn 2 O 4 . Hence, ACO NFs can be regarded as a promising sensing material for low-concentration n-butanol gas detecting. Also, the mechanisms for improving the sensing performance of ACO NFs based gas sensor are proposed.
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JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Jia-Qi Zheng,Jian Chen,Ming Zhu,Wen-Hui Chen,Ning-Ning Ma,Xiu-Min Yao,Zheng-Ren Huang
N-doped SiC-MoSi 2 ceramics were successfully fabricated by hot pressing in N 2 using Y(NO 3 ) 3 .6 H 2 O as both sintering aids and additional N sources. The impact of Y(NO 3 ) 3 .6 H 2 O content on the densification, electrical properties, and infrared emission performance of the resulting ceramics were investigated. The distribution of Y-based sintering aid is improved by melting of Y(NO 3 ) 3 .6 H 2 O during slurry drying, enabling the relative density to increase up to 97.4%. Y(NO 3 ) 3 .6 H 2 O subsequently decomposes during sintering and allows the substitution of atomic N for the C sites in SiC lattice and production of the N-derived donor level. A larger amount of N dopant elevates the carrier density up to 1.90 × 10 16 cm -3 . Remarkably, The SiC − 10 wt% MoSi 2 ceramics sintered with 16.9 wt% Y(NO 3 ) 3 .6 H 2 O exhibits the lowest electrical resistivity (0.791 Ω·cm at room temperature) and highest infrared emissivity (0.913 at 800 ℃), the latter of which may also be attributed to lattice distortion induced by N doping . This work demonstrates N doping as a prospective strategy for synergistically optimizing the electrical conduction and infrared emission performance of SiC-based ceramics for infrared source applications.
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Electrocatalysis
·
2017
·Vol. 9
·期 2
·264-270
·
IF 2.398
Zhang Lulu,Chen Yongting,Zhao Pingping,Luo Wei,Chen Shengli,Shao Minhua
One of the main challenges to generate hydrogen is to develop cheap and highly active electrocatalysts toward hydrogen evolution reaction (HER). Herein, Fe 3 C nanorods encapsulated in N-doped carbon nanotubes (Fe 3 C@NCNT) were synthesized by a simple method involving the pyrolysis of a Fe-based metal organic framework (MOF) and melamine. The hybrid composite showed an excellent catalytic activity toward HER in an acidic electrolyte. The overpotential at the current density of 10 mA cm −2 was only 154 mV in a 0.5 M H 2 SO 4 solution, which was lower than most of the non-precious metal and metal-free catalysts. Density functional theory (DFT) calculation results suggested that the synergistic effect between Fe 3 C nanorods and N dopants could effectively tune the H adsorption energy on carbon resulting in an enhanced HER activity.
Graphical Abstract
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ENZYME AND MICROBIAL TECHNOLOGY
·
2022
·
IF 3.705
Shi-Wei Zhao,Qian Zhou,Neng-Bing Long,Rui-Feng Zhang
A novel polymer support was prepared by curing of epoxy resin in ethanol solution in the macropores of a melamine sponge. The produced polymer gel could uniformly deposit on the surface of melamine in either porous or nonporous morphology. The composite sponge with porous coating can be used as a large-sized and well-mass transferred support for the immobilization of β-galactosidase from Bacillus circulans through method of adsorption and crosslinking, and a column reactor was made for the preparation of N-acetyllactosamine in a sealed circulation way. The porosity and specific surface area of the support were 91.6 % and 46 m 2 /g, respectively. The loading amount and the specific activity of immobilized β-galactosidase under the optimal immobilization conditions were 41.2 mg/g support and 16.5 U/mg protein , respectively. In the biosynthesis of N-acetyllactosamine lactose and N-acetylglucosamine were used as donor and acceptor, respectively. Under optimized conditions the N-acetyllactosamine yield reached 54 % within 150 min at 50 °C. After 10 cycles, the immobilized β-galactosidase retained 70 % of the original activity.
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PubMed
高影响因子
Frontiers of Chemical Science and Engineering
·
2021
·Vol. 15
·期 5
·1312-1321
·
IF 4.204
Wang Wei,Lv Haijun,Du Juan,Chen Aibing
In this present work, N-doped carbon nanobelts (N-CNBs) were prepared by a confined-pyrolysis approach and the N-CNBs were derived from a polypyrrole (Ppy) tube coated with a compact silica layer. The silica layer provided a confined space for the Ppy pyrolysis, thereby hindering the rapid overflow of pyrolysis gas, which is the activator for the formation of carbonaceous materials. At the same time, the confined environment can activate the carbon shell to create a thin wall and strip the carbon tube into belt morphology. This process of confined pyrolysis realizes self-activation during the pyrolysis of Ppy to obtain the carbon nanobelts without adding any additional activator, which reduces pollution and preparation cost. In addition, this approach is simple to operate and avoids the disadvantages of other methods that consume time and materials. The as-prepared N-CNB shows cross-linked nanobelt morphology and a rich porous structure with a large specific surface area. As supercapacitor electrode materials, the N-CNB can present abundant active sites, and exhibits a specific capacitance of 246 F·g −1 , and excellent ability with 95.44% retention after 10000 cycles. This indicates that the N-CNB is an ideal candidate as a supercapacitor electrode material.
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CHEMISTRY-A EUROPEAN JOURNAL
·
2017
·Vol. 23
·期 58
·14597-14603
·
IF 5.317
Xinghua Chen,Fei He,Yanfei Shen,Yiran Yang,Hao Mei,Songqin Liu,Toshiyuki Mori,Yuanjian Zhang
Graphical Interface effect : A study into the intrinsic role of carbon supports for Fe-N/C alternatives to Pt/C catalysts for oxygen reduction in fuel cells revealed that when immobilized on suitable support, the Fe−N/C demonstrated an improved mass J K that was comparable to that of Pt/C and higher than most reported M−N/C catalysts (see scheme). The mass kinetic current density (mass J K ) of most extensively reported M−N/C catalysts (M represents non-precious metal elements such as Fe, Co, and Cu), a potential alternative to noble metal catalysts in fuel cells, is poorer than that of commercial Pt/C. Thus, deep understanding of the intrinsic roles of carbon supports may contribute to the development of M−N/C catalysts from a practical point of view. Herein, the routinely used carbon supports, i.e. carbon black (CB) and carbon nanotubes (CNT) that have different morphology and crystallinity, were investigated to uncover the factors that affected the mass J K of Fe−N/C in electrocatalytic oxygen reduction. When immobilized on CB, the ionic liquids-derived Fe−N/C exhibited an enhanced mass J K (4.45 A g −1 at 0.80 V vs. RHE) by a factor of 2.14 times, comparable to that of Pt/C (5.79 A g −1 ) and higher than most reported M−N/C catalysts to our best knowledge. In contrast, the CNT support system showed no improvement. It was revealed that a compatible interface between the Fe−N/C precursors and the carbon supports was vital to ensure in-situ growth of a uniform catalyst layer on the supports during pyrolysis. This subsequently promotes the mass J K by exposing more embedded active sites and introducing favorable slit pores for effective mass-diffusion. This work would be promising to address the long-term overlooked challenge of the low mass J K of M−N/C catalysts in replacing noble-metal catalysts for practical fuel cell applications.
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PubMed
高影响因子
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
·
2022
·Vol. 2022
·期 33
·e202200316
·
IF 3.261
Yong Wang,Hui Wang,Qifan Yang,Shihua Xie,Hongjun Zhu
Graphical Herein, palladium(II)-catalyzed halogenation of 2-phenylquinazolines using N -halosuccinimides as halogen sources was described via C−H activation under mild reaction conditions. A series of halogen-substituted 2-arylquinazolines were synthesized through C−H functionalization. An efficient quinazoline-assisted ortho -halogenation of 2-arylquinazolines has been developed using N -halosuccinimides as halogen sources with Pd(II)-catalyzed C−H bond activation. No additional ligand and oxidant are required. This protocol is highly regioselective and applicable to a broad range of quinazoline substrates bearing different functional groups, giving yields of up to 98 %. The mechanism of the quinazoline ortho -halogenation was investigated by comprehensive experimentation.
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JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
·
2020
·Vol. 20
·期 2
·949-956
·
IF 1.134
Tang Ze-Hua,Xie Jin-Feng,Bian Zheng-Xu,Zhang Jun-Hao,Liu Yuan-Jun,Guo Xing-Mei,Kong Qing-Hong,Yuan Ai-Hua
To improve lithium storage performances of Si anode for lithium-ion batteries, Si nanoparticles encapsulated into porous N-doped carbon (Si@PNC) was devised and prepared by metal nitrate accelerated polymer blowing process. The Si@PNC composites have large specific surface area of 221.7
m2 g-1 and possess a great deal of mesopores and micropores, which are attributed to the carbonization of PVP and etching metallic nanoparticles. As anode for lithium ion battery, the initial discharge capacity of Si@PNC composites is high to 1626 mA h g-1,
and the specific capacity still retains 1030 mA h g-1 after 200 cycles at 200 mA g-1. Meanwhile, remarkably improved rate capability is achieved with an excellent reversible specific capacity of 375 mA h g-1 at 5.0 A g-1. The excellent lithium storage
performances benefit from the unique porous core–shell structure of Si@PNC composites, which improve electroconductivity, reduce volume dilatation and accelerate lithium ion transmission.
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PubMed
高影响因子
TEXTILE RESEARCH JOURNAL
·
2015
·
IF 1.599
Guangqing Zhuang,Wei Ping,Yun Zhang,Yanrong Jia,Lan Zhou,Qinguo Fan,Jianzhong Shao
Structural coloration is a kind of biomimetic coloring technology. (Silica/polyethyleneimine)n (SiO2/PEI)n films with structural color on the surface of silk fabrics were fabricated by the electrostatic self-assembly method. The structural color of silk fabrics with (SiO2/PEI)n films was captured by a digital camera, and the reflectance spectra were measured by the DigiEye system and a multi-angle spectrophotometer. The morphological structure of (SiO2/PEI)n films on silk fabrics was observed by a field emission scanning electron microscope. The coloring mechanism of the silk fabrics is in agreement with single thin film interference theory, and the variability of the structural color on the silk fabrics is similar to those on polyester fabrics varying with the assembly cycles, particle sizes and viewing angles. However, the color brilliance, brightness and iridescence effect of the silk fabrics are inferior to those of polyester fabrics with the same films, due mainly to the differences in fiber surface structure and microstructure between silk fibers and polyester fibers.
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APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Xianyi Tang,Cheng Tong,Lianqiao Tan,Zidong Wei,Meng Wang
Lithium-Sulfur Batteries (LiSBs) are prevented to apply in practice by the irreversible loss from the cathode and difficult conversation kinetics of lithium polysulfides (LiPSs). An ideal S host material should possess high conductivity and sufficiently dispersed catalytic active sites to precisely restore the dissolved LiPSs to the surface of the S host material. In traditional catalyst design, porous carbonaceous materials are often selected as carriers for the nano-catalytic activity sites. However, non-polar pure carbon interfaces, where without nano-catalytic activity sites covered, have a very weak affinity to LiPSs. Here, we use ammonia as a nitrogen source to anneal the reduced aerogel (graphene oxide (rGO) supported nano-TiO 2 ) at high temperatures. The N element is atomically doped into the lattice of the carbon matrix, and the nano-TiO 2 is converted to nano-TiN. A hierarchically porous and high conductivity TiN/N-C is prepared, in which the nano-TiN is well dispersed on the surface of N-doped rGO as an active center for catalyzing LiPSs conversion. The doped-N elements significantly increase the proportion of the polar surface. The S@TiN/N-C composite cathode delivered an excellent long-life cycling performance, and the reversible discharge specific capacity faded from 1224 ± 16 to 675 ± 31 mAh g −1 after 930 cycles. More importantly, after 150 cycles with a high S loading, a reversible areal capacity of 4.1 mAh cm −2 can be achieved.
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ChemElectroChem
·
2022
·Vol. 9
·期 22
·e202200715
·
IF 4.782
Wei-Xiang Cheng,Yi-Zhao Chen,Song-Yi Liao,Jun-Qi Hu,Cun-Sheng Liu,Shuai-Fu Cui,Xing-Wen Huang,Yidong Liu,Yonggang Min
Graphical NIB news : MoS 2 anchored on nitrogen-doped MXene nanosheets with carbon coating were prepared and applied in Na-ion batteries (NIBs). It remained at ∼308 mAh g −1 at 0.5 A g −1 after 300 cycles and showed higher rate performance of ∼189 mAh g −1 at 4 A g −1 . The MoS 2 @N-MXene/C heterogeneous nanosheets showed enhanced pseudocapacitance effects of 84.5 % at a scan rate of 2 mV s −1 according to CV curves simulation. Currently, Na-ion batteries (NIBs) have emerged as a new generation of energy storage devices. However, due to the lack of suitable anode materials, the large-scale practical application of NIBs is still greatly limited. Therefore, to address this issue, an effective strategy towards an advanced NIBs anode was developed by achieving MoS 2 anchored on nitrogen-doped MXene nanosheets with carbon coating (shorten as MoS 2 @N-MXene/C). The structure, surface chemistry state and micromorphology of MoS 2 @N-MXene/C were carefully analyzed and characterized by XRD, XPS and SEM/TEM, respectively. It was shown that MoS 2 was loaded on N-MXene to form a heterogeneous nanosheets structure. When applied to the anode of NIBs, MoS 2 @N-MXene/C delivered ∼189 mAh g −1 at 4 A g −1 and remained at ∼308 mAh g −1 after 300 cycles at 0.5 A g −1 . Moreover, based on the simulation and calculation from CV curves, the enhanced electrochemical performances of MoS 2 @N-MXene/C was assigned to its high pseudocapacitance-dominated contribution (84.5 % at a scan rate of 2 mV s −1 ). Therefore, owing to the highly conductive N-MXene and the actively anchored MoS 2 , MoS 2 @N-MXene/C could effectively provide efficient channels for charge transfer and ionic diffusion. The presented design strategy may provide a guidance for developing more-efficient NIBs anode.
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