RSC Advances
·
2023
·Vol. 13
·期 6
·3835-3842
·
IF 3.9
Tanlun Wang,Lincheng Xu,Chenxiang Sun,Xiyuan Li,Yong Yan,Fan Li
Fe–N–C has a high number of FeNx active sites and has thus been regarded as a high-performance oxygen reduction reaction (ORR) catalyst, and combining Fe3C with Fe–N–C typically boosts ORR activity. However, the catalytic mechanism remains unknown, limiting further research and development. In this study, a precipitation-solvothermal process was used in conjunction with pyrolysis to produce a series of Fe–N–C catalysts derived from a zeolitic imidazolate framework (ZIF) that was composited with Fe3C. The prepared catalysts had a multiscale structure of ZIF-like carbon particles and rod-like structures, as well as bamboo-like carbon nanotubes (CNTs) and carbon layers wrapped with Fe3C particles while a series of studies revealed the origin of the rod-like structures and Fe3C phase. The hierarchical structure was beneficial to the enhanced electrocatalytic performance of catalysts for ORR. The optimal sample had the highest half-wave potential of 0.878 V vs. RHE, which was higher than that of commercial Pt/C (0.861 V vs. RHE). The ECSA of the optimal sample was 1.08 cm2 μg−1, with an electron transfer number close to 4, and functioning kinetics. The optimal sample exhibited high durability and methanol tolerance for the ORR. Finally, blocking different Fe active sites with coordination ions demonstrated that Fe(II) was the main active site, indicating that Fe3C primarily served as a cocatalyst to optimize the electron structure of Fe–N–C, thereby synergistically improving the ORR activity.
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PubMed
高影响因子
Advanced Materials Interfaces
·
2022
·Vol. 9
·期 5
·2101877
·
IF 6.389
Chao Wang,Yuan Ha,Xin Mao,Weilan Xu,Aijun Du,Renbing Wu,Shulei Chou,Haijiao Zhang
The exploration of high-efficiency and inexpensive electrocatalysts for oxygen reduction reaction (ORR) is of critical significance for renewable energy conversion. Herein, an in situ catalytic transformation strategy toward a unique hierarchical nanostructure is reported. In the architecture, Co nanoparticles encapsulated at the tip of bamboo-like N-doped carbon nanotubes (NCNTs) are grafted on N-doped polypyrrole-derived CNTs. Thanks to the smart design of unique 3D architecture, the NPCN@Co-NCNTs catalyst displays an extraordinary ORR activity in 0.1 m KOH solution (the onset and half-wave potentials are 0.96 and 0.90 V vs RHE, respectively), which is similar to commercial Pt/C catalyst (0.99 and 0.88 V vs RHE, respectively). Meanwhile, the catalyst shows the low Tafel slope of 78 mV dec −1 and long-time stability. Experimental and theoretical results verify that the improved ORR performance is mainly related to the existence of Co nanoparticles protected by pyridinic-N-doped carbon, which lowers the theoretical overpotential of ORR. Density functional theory calculations reveal that Pyridinic-NC Co site is the reactive site with the lowest overpotential for ORR (0.57 V). These results unambiguously indicate that the NPCN@Co-NCNTs represent a low-cost yet high-efficiency electrocatalyst for the electrocatalytic ORR.
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高影响因子
Advanced Composites and Hybrid Materials
·
2022
·Vol. 5
·期 2
·991-1002
·
IF 11.806
Xu Pei,Huang Bincheng,Tang Ruobing,Wang Zhenfeng,Tu Jiaying,Ding Yunsheng
The functionalization and distribution of conductive fillers and the interfacial compatibilization of polymer blends is the basic scientific problem of electromagnetic interference (EMI) shielding composites. Polylactic acid/polycaprolactone (PLA/PCL)-based nanocomposites containing polymerizable ionic liquid copolymer of poly(methoxy poly(ethylene glycol) monomethacrylate-co-1-vinyl-3-ethylimidazolium bromide) (PILs) and multi-walled carbon nanotubes (CNTs) were fabricated by the melt blending. The high affinity of MEPGMA segments of PILs for both phases and the interaction between the imidazole group of PILs and CNTs improved the dispersion and compatibility of CNTs in the matrix. PILs could expand to the interfacial layers as compatibilizers because of the high affinity of MEPGMA groups for polymer phases. The migration of CNTs from PLA to PCL phase was realized by the kinetic control and PIL-modified CNTs were selectively distributed at the co-continuous PLA/PCL interface and PCL phase of the PLA/PCL/4PIL/8CNT-6 m composite with blending time of 6 min. The selective localization of CNTs at interphase significantly can form effective conductive networks at the interface for PLA/PCL/4PIL/8CNT-6 m composite, which increase the electrical conductivity of the composite. The EMI shielding efficiency of the PLA/PCL/4PIL/8CNT-6 m composites, which can reflect and absorb microwaves with multiple times, reaches up to the maximum value 41 dB. Graphical abstract
The selective localization of CNTs at interphase forms effective conductive network. EMI SE of the PLA/PCL/4PIL/8CNT-6 m composite displays 41 dB.
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高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Xue Guo,Junbin Lu,Jie Liu,Chunmiao Liu,Yanchun Tong,Jiao Li,Haibin Sun,Hui Peng,Shigang Wu,Yurun Feng,Hongyu Gong
By utilizing polymer-derived ceramics (PDCs) method and electrospinning technology, SiCN(Ni) fibers with 1 wt% nickel content at different calcination temperatures (1000–1300 °C) were synthesized. The properties of PDCs-SiCN(Ni) fibers were tested by XRD , SEM, TEM, Raman spectroscopy , XPS and vector network analyzer. The results showed that the addition of nickel acetylacetonate (NA) promoted the in-situ formation of CNTs and Ni 2 Si at high temperatures, which could adjust the impedance matching performance and improve the electromagnetic wave (EMW) absorption properties. The minimum reflection loss (RL) of SiCN(Ni) fibers was −47.55 dB (4.2 mm), and the effective absorption band (EAB, RL ≤ −10 dB) was 3.6 GHz (14.4–18 GHz) under the ultra-thin thickness of 1.24 mm.
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高影响因子
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
·
2020
·
IF 4.652
Yongchao Shan,Bowen Pu,Enzuo Liu,Chunsheng Shi,Chunnian He,Naiqin Zhao
For nanocarbon reinforced aluminum matrix composites (AMCs), the architecture design of reinforcements is an effective route to obtain superior mechanical performances. In this work, a novel AMC reinforced by CNTs wrapped with γ-Al 2 O 3 (CNTs@Al 2 O 3 ) reinforcement with balanced strength and toughness was fabricated by powder metallurgy methods. The wrapping structure of γ-Al 2 O 3 was synthesized through the in-situ reactions of Al matrix and boric acid decorated CNTs, thus improving the interface coupling of the composite. The CNTs@Al 2 O 3 /Al composite with the addition of 0.5 wt% CNTs and 10 wt% in-situ Al 2 O 3 exhibited a mean ultimate tensile strength of 404 MPa, which is significantly higher than unreinforced pure Al (183 MPa) and those reinforced by individual CNTs (207 MPa) or Al 2 O 3 (289 MPa). An improvement of ductility was also achieved in CNTs@Al 2 O 3 /Al composites compared with the Al 2 O 3 /Al composites with the same Al 2 O 3 content. The synergistic strengthening and toughening effects are ascribed to the ingenious in-situ CNTs@Al 2 O 3 wrapped structure, which highlights the importance of architecture design of reinforcements in AMCs, and sheds new light on the development of CNT-reinforced AMCs.
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高影响因子
APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Deqing Zhang,Honghan Wang,Junye Cheng,Changyu Han,Xiuying Yang,Jingyu Xu,Guangcun Shan,Guangping Zheng,Maosheng Cao
Herein, ultra-thin tungsten disulfide nanosheets/carbon nanotubes (WS 2 -NS/CNTs) hybrids were successfully synthesized by using a one-step hydrothermal method. The WS 2 -NS is evenly grown on the surfaces of CNTs , leading to a remarkable three-dimensional (3D) heterostructure. Outstanding electromagnetic wave absorption performance of the WS 2 -NS/CNTs hybrids can be achieved by tuning the amount of CNTs. The minimum reflection loss can reach up to −51.6 dB at 14.8 GHz, and the effective absorption bandwidth is 5.4 GHz for the hybrids with a thickness of 1.95 mm. Comparison of the results with those of simple mixtures of WS 2 -NS and CNTs prepared by using ultrasonic methods indicates that the absorption performance of the optimized WS 2 -NS/CNTs hybrids are closely related to that of the 3D mesh conductive network constructed by the addition of CNTs and the synergistic effect of WS 2 -NS and CNTs in the hybrids. These WS 2 -NS/CNTs hybrids open a new avenue for the development of electromagnetic wave absorbers with extraordinary absorption performance, light weight, small thickness, broad absorption bandwidth, and low cost.
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高影响因子
CHEMOSPHERE
·
2019
·
IF 5.108
Yunbo Liu,Yunlan Peng,Baohua An,Laicai Li,Yong Liu
In order to investigate the adsorption behaviors of sulfonamides onto hydroxylated multi - walled carbon nanotubes (CNTs) with a porous structure and large specific surface area, six typical sulfonamides including sulfanilamide (SAM), sulfamerazine (SMR), sulfadimethoxine (SMX), sulfadiazine (SDZ), sulfamethazine (SMT) and sulfametoxydiazine (SMD) were selected to be adsorbed respectively on CNTs, and in the same time the structural parameters of the six sulfonamides molecules were calculated according to the density functional theory (DFT). Based upon above mentioned experiments and the structural parameters, the quantitative correlation between the structural parameters of sulfonamides molecules and their adsorption affinity (e.g. adsorption capacity and adsorption rate constant) onto CNTs was established, respectively. The adsorption data of sulfonamides fitted well with the pseudo - second - order kinetic model and the Langmuir isotherm model. The order of both pseudo - second - order kinetic constant and maximum adsorption capacity of the six sulfonamides were SAM < SMR < SMX < SDZ < SMT < SMD. The frontier molecular orbital energy (E HOMO ) and dipole moment (μ) could be used as indicators for the adsorption affinity of sulfonamides onto CNTs. Accordingly, the possible adsorption mechanism was proposed.
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PubMed
高影响因子
Biomaterials Advances
·
2022
·
IF 0
Yingchun Li,Yannan Liu,Bo Peng,Xinyue Li,Tianshu Fang,Shuai Liu,Jiachen Liu,Bo Li,Fei Li
Deep skin wound needs a long wound healing process, in which external force on skin around wound can result in a sharp pain, wound re-damage and interstitial fluid flowing out, increasing the risk of deterioration and even amputation. While the conventional wound dressings cannot provide timely feedback of abnormal wound status and lose best time for wound treatment, real-time monitoring wound status is thus urgently needed for wound management. In this work, a breathable and stretchable electronic skin ( i.e. , e-skin) named CNTs/graphene/GelMA mat has been developed through electrospinning, ice-templating and in-situ loading method for evaluating wound status. The obtained porosity, swelling ratio and vapor transmission rate of the CNTs/graphene/GelMA mat are 55 %, 180 % and 3378.2 h −1 day −1 , respectively. And owing to the good porous, nanofibrous architecture and excellent breathability of the mat, L929 cells grow and well spread on the CNTs/graphene/GelMA mat. In addition, the gauge factors of the prepared conductive CNTs/graphene/GelMA mat as a strain sensor are 15.4 and 72.9 in the strain ranges of 0–70 % and 70–85 %, respectively, matching the mechanical performance of human skin. The sensitivity coefficient of the mat for moisture sensing is 12.05, indicating its high efficiency for monitoring and warning interstitial fluid outflow from wound. Furthermore, the integration of CNTs/graphene/GelMA mat with a portable device is feasible to monitor strain and moisture on a rat model with abdominal wound. The healing process of the wounds treated with CNTs/graphene/GelMA mat is similar to that of GelMA mat, indicating that the dosage of CNTs and graphene in the CNTs/graphene/GelMA mat has negligible effect on the mat histocompatibility. The CNTs/graphene/GelMA mat demonstrates the application potential in wound management, home medical diagnosis and human-machine interactions.
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Journal of Water Process Engineering
·
2023
·
IF 7
Xinrui Liu,Rui Guo,Xia Qin,Cuicui Xu
In this work, a Ni foam/CNTs/Cu composite electrode was prepared via the impregnation and electrodeposition methods. The electrode enhanced the total nitrogen removal and N 2 selectivity , when served as a cathode for NO 3 − -N reduction. SEM, EDS, XRD, and XPS characterization revealed that both CNTs and metallic copper were introduced onto the surface of the Ni foam substrate successfully. Besides, the LSV, CV, EIS and C dl results indicated more electrochemical active sites were in the Ni foam/CNTs/Cu electrodes than in Ni foam/Cu electrodes. Under optimal preparation conditions, the Ni foam/CNTs/Cu electrode showed N 2 selectivity of 68.89 % and nitrate removal rate of 96.75 % in 100 mg/L nitrate solution with Na 2 SO 4 as electrolyte. The selectivity of N 2 could be significantly enhanced by adding Cl − as electrolyte, and the nitrogen selectivity increased with the increase of Cl − concentration. At 1.25 g/L NaCl, the Ni foam/CNTs/Cu electrode could achieve >95 % nitrate and total nitrogen removal and close to 100 % N 2 selectivity. The N 2 selectivity of the Ni foam/CNTs/Cu electrode was 2.534 and 1.8 times of the Ni foam/Cu electrode when 0.5 g/L Na 2 SO 4 and 0.5 g/L NaCl were used as electrolytes, respectively. Consequently, to achieve the same nitrate reduction effect, the Ni foam/CNTs/Cu electrode could reduce the amount of NaCl compared with Ni foam/Cu electrode. The electrodes were tested in 6 cycles and proved to be stable. At last, a potential mechanism of nitrate‑nitrogen removal by the electrocatalytic process was suggested.
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高影响因子
Journal of Energy Storage
·
2023
·
IF 9.4
Haidong Xie,Chunping Hou,Yuqing Qu,Hui Tian,Hui Lu,Jiandong Wu,Shaolin Yang,Yong Ma
SiO x has become one of the most promising anode materials for lithium ion batteries due to its high specific capacity, abundant natural resources and suitable lithium insertion and extraction voltage. However, the low conductivity and the poor cycle performance seriously hinder its practical application. In here, a simple and effective method is proposed to disperse SiO x between carbon materials including flake graphite, reduced graphene oxide (rGO) and carbon nanotubes (CNTs), and then micron-sized N-SiO x /graphite/rGO-CNTs@C (N-SiO x /C@C) composite with dense structure is prepared by coating and pyrolysis of pitch. The synergistic effect of various carbon materials is beneficial to improve the conductivity of the material, and maintain the structural integrity during the cycle. The obtained N-SiO x /C@C anode exhibits high reversible capacity (980.2 mAh·g −1 ), excellent cycle stability (70 % capacity retention after 500 cycles at 0.5 A·g −1 ) and excellent rate performance (491.9 mAh·g −1 specific capacity of at 5 A·g −1 ). The strategy provided here effectively improves the electrochemical performances of SiO x , and the prepared materials show great application potential in the field of lithium ion batteries.
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高影响因子
APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Ying Mao,Langping Wang,Xiaofeng Wang
In order to improve the current-carrying properties of AgCu10 alloy, AgCuS-carbon nanotubes (CNTs) composite coatings were synthesized on AgCu10 substrates using an in-situ sulfide method. During the process, an entangled CNTs layer was formed firstly on the AgCu10 substrate by dipping the substrate into a CNTs dispersant and dried at room temperature, then an AgCuS-CNTs coating was synthesized in-situ by immersing the substrate with the CNTs layer in a 0.1 M Na 2 S solution. The current-carrying friction performance of the composite coating was significantly improved. Compared with the AgCu10 substrate, the friction coefficient was decreased from ∼0.35 to ∼0.15, and the wear rate was reduced by 2 orders of magnitude. Furthermore, the electrical resistivity of the coatings was as low as 2.44 × 10 −6 Ω·cm, which was almost the same as the AgCu10 substrate.
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高影响因子
FOOD CHEMISTRY
·
2023
·
IF 8.8
Qian Wu,Li Tian,Xiangyu Shan,Huiling Li,Shuning Yang,Chao Li,Juan Lu
In this work, a novel electrochemiluminescence (ECL) sensor based on the CdSe@ZnSe and CNTs was constructed for the detection of melamine. CdSe@ZnSe acted as the co-reaction promoter for the enhancement of Ru(bpy) 3 2+ /tri- n -propylamine (TPrA) system and CNTs acted as carriers to immobilize more CdSe@ZnSe. The initial ECL signal significantly amplified due to the synergistic effect of CNTs and CdSe@ZnSe. The ECL signal decreased with the addition of melamine, and the change value of ECL intensity (ΔI) was linearly related to the logarithm of melamine concentration. The constructed ECL sensor was able to detect melamine in the range of 1.0 × 10 −11 − 1.0 × 10 −7 M, and the detection limit was 3.3 × 10 −12 M (S/N = 3). It can be used to detect melamine in milk samples.
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高影响因子
危险品化学品经营许可证（带存储）