Nanomaterials
·
2021
·Vol. 11
·期 11
·2857
·
IF 5.076
Hui Wang,Qing Dong,Lu Lei,Shan Ji,Palanisamy Kannan,Palaniappan Subramanian,Amar Prasad Yadav
Structural engineering is an effective methodology for the tailoring of the quantities of active sites in nanostructured materials for fuel cell applications. In the present study, Co nanoparticles were incorporated into the network of 3D nitrogen-doped carbon tubes (Co@NCNTs) that were obtained via the molten-salt synthetic approach at 800 °C. Morphological representation reveals that the Co@NCNTs are encompassed with Co nanoparticles on the surface of the mesoporous walls of the carbon nanotubes, which offers a significant active surface area for electrochemical reactions. The CoNPs/NCNTs-1 (treated with CaCl2) nanomaterial was used as a potential candidate for the electro-oxidation of hydrazine, which improved the response of hydrazine (~8.5 mA) in 1.0 M NaOH, as compared with CoNPs/NCNTs-2 (treated without CaCl2), NCNTs, and the unmodified GCE. Furthermore, the integration of Co helps to improve the conductivity and promote the lower onset electro-oxidation potential (−0.58 V) toward the hydrazine electro-oxidation reaction. In particular, the CoNPs/NCNTs-1 catalysts showed significant catalytic activity and stability performances i.e., the i-t curves showed notable stability when compared with their initial current responses, even after 10 days, which indicates the significant durability of the catalyst materials. This work could present a new approach for the design of efficient electrode materials, which can be used as a favorable candidate for the electro-oxidation of liquid fuels in fuel cell applications.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
LANGMUIR
·
2024
·
IF 3.7
Jun-Yang Yan,Chun-Yan Cao,Gui-Ping Cao,Shao-Feng Pan,Hui Lv,Alaaddin M. M. Saeed
Traditional heterogeneous catalysts are affected in the catalytic hydrogenation of PS by the scale effect, viscosity effect, adhesion effect, and conformational effect, resulting in poor activity and stability. Monolithic Pd-CNTs@FN catalysts could eliminate or weaken the impact of these negative effects. We grew nitrogen-doped carbon nanotubes (NCNTs) on monolithic-foamed nickel (FN) and investigate their growth mechanism. Meanwhile, the feasibility of using the NCNTs@FN carrier for PS hydrogenation reaction was also verified. The growth of NCNTs on FN can be divided into 3 stages: initial growth stage, stable growth stage, and supersaturation stage. Finally, a three-layer structure of NCNT layer, dense carbon layer, and FN skeleton is formed. Two types of structures, nickel-doped carbon nanotubes (NiCNTs) and C–Ni alloy, are formed by combining C and Ni, while four nitrogen-doped structures, NPD, NPR, NG, and NO, are formed by C and N. The prepared carrier exhibited an extremely outstanding specific surface area (2.829 × 106 cm2/g) and strength (no NCNTs falling off after 24 h 500 rpm agitation), as well as high catalytic activity for PS hydrogenation after loaded with Pd (2.13 ± 0.95 nm), with a TOF of up to 27.6 gPS/(gPd•h). After 8 repetitions of the catalyst, there was no significant decrease in activity. This proves the excellent performance of Pd-NCNTs@FN in polymer hydrogenation reactions, laying a solid foundation for further research on the mechanism of NCNTs promoting PS hydrogenation and regulating the growth of NCNTs.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2020
·
IF 16.683
Lijun Yang,Hui Li,Yang Yu,Yang Wu,Lei Zhang
A binder-free electrode with metallic Co embedded in N-doped carbon nanotube array (Co@N-CNT) was fabricated via an electrodeposition , stereoscopic assembly and self-boosting catalytic pyrolysis . Specifically, directed-eletrodeposition vertical growth of Co(OH) 2 -nanosheet serves as the structure inducer to offer abundant sites for ZIF-67 growth, and melamine is selected as an initiator for orientated growth of N-CNTs. As an integrative non-noble electrocatalyst for water splitting, it requires only 1.58 V to achieve 30 mA cm −2 in an alkali-electrolyzer. The remarkable electrochemical performance is mainly attributed to the unique 3D hierarchical tubular structure and the synergistic effect of each chemical compositions, which provide amount of accessible active sites, accelerate the diffusion of electron/electrolyte, and improve the electrical conductivity, hydrophilicity and structural stability. The electro-catalytic splitting water mechanism was further explored by density functional theory. This universal method can be extensively applied to fabricate well-defined monometal or bimetal encapsulated into N-CNTs for various electrochemical applications.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
ANALYTICA CHIMICA ACTA
·
2019
·
IF 5.256
Yuheng Guo,Xue He,Chuanhui Huang,Hui Chen,Qiaomei Lu,Lan Zhang
An efficient and stable adsorbent is of critical importance for solid-phase microextraction (SPME). In this study, we prepared metal–organic framework-derived nitrogen (N)-doped carbon (C) nanotube cages (N-CNTCs) with unique N-doped active sites and C-rich nanotubes to coat SPME adsorbents. This new material was obtained via a simple thermal treatment with ZIF-67, and exhibited high porosity and excellent chemical and thermal stability . Compared with commercial fibers and traditional C nanotubes-coated fiber (15 nm), N-CNTC-coated fiber exhibited better extraction properties, mainly due to its π–π interactions, abundant active sites, and hollow cage structure, which is composed of interconnected crystalline N-doped C nanotubes. N-CNTC-coated fiber exhibited better extraction performance and shorter extraction equilibrium time than the solid N-doped C-coated fiber due to its hollow cage structure. The N-CNTC-coated fiber was then used to identify polychlorinated biphenyls (PCBs) with wide linear range (0.3–1000.0 ng L −1 ), low limits of detection (0.10–0.22 ng L −1 ), good repeatability (intra-day, 2.6–3.8%; inter-day, 3.3–4.8%), and good reproducibility (<8.6%). We then successfully applied the N-CNTC-coated fiber to detect PCBs in river water samples from six cities in Fujian Province and obtained satisfactory recovery levels. Thus, the novel N-CNTCs coating proposed in this study is a promising candidate for SPME coating.
研究领域:
分析化学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ELECTROCHIMICA ACTA
·
2015
·
IF 4.504
Xingping Lu,Yating Hu,Li Wang,Qiaohui Guo,Shuiliang Chen,Shouhui Chen,Haoqing Hou,Yonghai Song
A novel kenaf stem-derived porous carbon/nitrogen-doped carbon nanotubes/polyaniline (denoted as KSC/NCNTs/PANI) nanocomposite was constructed in this work. Three-dimensional (3D) KSC/NCNTs nanocomposites were firstly constructed through a CVD method. The NCNTs were densely distributed on the channel walls of KSC, which increased both the effective surface area and the active sites greatly. Then, the PANI was grown on the KSC/NCNTs by using in situ chemical oxidation polymerization method. The obtained 3D KSC/NCNTs/PANI nanocomposites were carefully characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and Raman spectra. The nanocomposites were employed as the electrode materials of supercapacitors owing to their unique advantages originating from both PANI (e.g. interesting electroactivity, high pseudocapacitance, unusual doping/dedoping chemistry) and KSC/NCNTs (e.g. large specific surface area, high porosity, good electrical conductivity), and exhibited a high specific capacitance. At the current density of 0.1 A g −1 , the KSC/NCNTs/PANI nanocomposites showed a specific capacitance of 1090 F g −1 with a specific energy density around 97 Wh kg −1 . Moreover, the specific capacitance remained 96.9% after 1000 charging/discharging cycles at a current density of 0.1 A g −1 .
研究领域:
材料科学
·
能源存储
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2021
·
IF 5.816
Cong Wang,Zhili Wang,Hongli Wang,Yue Chi,Minggang Wang,Daowen Cheng,Jingjing Zhang,Chen Wu,Zhankui Zhao
Developing an efficient catalyst for hydrogen (H 2 ) generation from hydrolysis of ammonia borane (AB) to significantly improve the activity for the hydrogen generation from AB is important for its practical application. Herein, we report a novel hybrid nanostructure composed of uniformly dispersed Co@Co 2 P core-shell nanoparticles (NPs) embedded in N-doped carbon nanotube polyhedron (Co@Co 2 P/N–CNP) through a carbonization-phosphidation strategy derived from ZIF-67. Benefiting from the electronic effect of P doping, high dispersibility and strong interfacial interaction between Co@Co 2 P and N-CNTs, the Co@Co 2 P/N–CNP catalyst exhibits excellent catalytic performance towards the hydrolysis of AB for hydrogen generation, affording a high TOF value of 18.4 mol H 2 mol metal −1 min −1 at the first cycle. This work provides a promising lead for the design of efficient heterogeneous catalysts towards convenient H 2 generation from hydrogen-rich substrates in the close future.
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2022
·
IF 4.326
Zhihui Cai,Duo Liu,Jiangnan Huang,Jianning Feng,Hongjuan Wang,Guangxing Yang,Feng Peng,Yonghai Cao,Hao Yu
As an important raw material for the synthesis of polycaprolactone, a significant alternative for the nondegradable plastic, ε-caprolactone (ε-CL) monomer is typically produced through the Baeyer–Villiger oxidation of cyclohexanone (Cy═O). In this work, a solvent-free, highly efficient, and nonmetallic catalytic system was developed to produce the ε-CL monomer with dioxygen as the oxidant and benzaldehyde (BEA) as the co-oxidant. Nitrogen-doped carbon nanotubes (NCNTs) as the catalyst boost the catalytic activity (10.09% conversion, 10.06% yield of ε-CL), much higher than other carbon catalysts. The normalized specific activity of NCNTs reached 2964.80 mmol/g/h and 20.02 mmol/m2/h, which are 2–4 orders of magnitude higher than the state-of-the-art catalysts. The structure-dependent activity result shows that the ratio between pyridine nitrogen (NP) and graphite nitrogen (NG) on the surface of NCNTs positively affects the catalytic performance. Oxygen functionalities on the NCNT surface inhibit the activity by suppressing the auto-oxidation of BEA, which unexpectedly increases aldehyde efficiency. Finally, this process could be scaled up to a molar-scale reaction with a similar activity, which lays down the foundation of the industrial application of the solvent-free Baeyer–Villiger oxidation catalyzed by nanocarbons.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
DOI
高影响因子
Sustainable Energy & Fuels
·
2020
·Vol. 4
·期 8
·3926-3933
·
IF 5.503
Tao Long,Fancheng Meng,Bin Xu,Yixin Zhao,Weilin Liu,Xiangfeng Wei,Lianxi Zheng,Jiehua Liu
Porous carbon structures are considered as desirable electrode materials for Li–S batteries due to their flexible texture, high surface areas, and good conductivities. However, polymer carbonized materials usually suffer from limited electrical conductivity that will finally restrain the battery's electrochemical performance. Herein, in this paper, polyaniline (PANI) hydrogels are firstly synthesized on a template of conductive N-doped carbon nanotubes (NCNTs) via a solution process. After carbonization and activation treatments, the composite materials reveal a highly porous carbon (HPC) structure interwound by NCNT wires, demonstrating a high specific surface area of 1861 m2 g−1 and a high electrical conductivity. After further incorporation of elemental sulfur, the resultant NCNTs@HPC/S cathode exhibits excellent electrochemical properties with a superior initial capacity of 1506 mA h g−1 at 0.2C, a stable capacity of 613 mA h g−1 after 250 cycles, and an obviously improved rate performance. This work suggests a feasible and efficient approach to fabricate carbon-based high-performance Li–S battery cathodes.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
ChemSusChem
·
2020
·Vol. 13
·期 21
·5683-5689
·
IF 7.962
Zhenbing Xie,Bingfeng Chen,Fangfang Peng,Mingyang Liu,Huizhen Liu,Guanying Yang,Buxing Han
Graphical A sustainable conversion : Developing highly efficient catalytic systems for amino acid productions from renewable bio-derived chemicals is very attractive for a sustainable future. N-doped carbon nanotube-supported Ru nanoparticles (Ru/N−CNTs) display excellent performance in the amination of bio-derived hydroxy acids into amino acids. The high-performance can be correlated with high dispersion of Ru nanoparticles and electronic effect resulting from the N-dopant. The amino acids have extensive applications, and their productions from biomass-derived feedstocks are very attractive. In this work, the synthesis of amino acids by amination of bio-derived hydroxy acids with ammonia over different metallic nano-catalysts supported on various supports is studied. It is found that Ru nano-catalysts on the nitrogen-doped carbon nanotubes (Ru/N−CNTs) have an outstanding performance for the reaction. Different hydroxy acids can be catalytically converted into the corresponding amino acids with yields up to 70.0 % under mild conditions, which is higher than those reported. The reasons for the high efficiency of the catalyst are investigated, and the reaction pathway is proposed on the basis of control experiments.
研究领域:
生物化学
·
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2016
·Vol. 4
·期 46
·18008-18014
·
IF 8.262
Hongli An,Ruikang Zhang,Zhenhua Li,Lei Zhou,Mingfei Shao,Min Wei
Nitrogen-doped carbon nanotubes (NCNTs) are recognized as one of the most promising oxygen reduction reaction (ORR) catalysts, while developing a preparation protocol for CNT-based ORR catalysts with cost-effective synthesis, high activity and durability is still a challenge. In this work, we report the fabrication of N-doped CNT catalysts with a homogeneous distribution of dopants in the CNT matrix by pyrolysis of a core–shell nanostructured CNTs@polypyrrole nanocomposite (CNTs@PPy). The as-obtained NCNTs exhibit excellent performance in electrocatalytic oxygen reduction with an onset potential of 0.95 V vs. RHE, a diffusion-limited current of 6.82 mA cm−2 and excellent stability in alkaline media, much superior to that of reported CNT-based ORR catalysts as well as commercial Pt/C. Moreover, the ratio of different nitrogens (pyridinic, pyrrolic and graphitic N) can be tuned easily by changing the coating amount of PPy in the CNTs@PPy core–shell precursors; and the results indicate that the pyridinic-N in the CNTs@PPy derived NCNTs plays a key role in promoting the ORR performances.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
ChemElectroChem
·
2020
·Vol. 7
·期 3
·745-752
·
IF 4.154
Pan Wang,Ji Qi,Chuang Li,Xiao Chen,Tonghua Wang,Changhai Liang
Graphical One for all : A new strategy is used to grow N-doped carbon nanotubes encapsulating Ni/MoN heterostructures on carbon cloth, exhibiting highly active and stable for overall water splitting, which originates from the high intrinsic activity in the interface of the Ni/MoN heterostructures, the high conductivity and protection of carbon nanotubes, and the three-dimensional structure of the Ni/MoN@NCNT/CC. Herein, we reported a new strategy to grow N-doped carbon nanotubes encapsulating Ni/MoN heterostructures on carbon cloth (Ni/MoN@NCNT/CC). The high intrinsic activity in the interface engineering of the Ni/MoN heterostructures, the high conductivity and protection of NCNT, and the three-dimensional structure of the Ni/MoN@NCNT/CC contribute to its outstanding activity and stability for HER (overpotential of 207 mV at 10 mA cm −2 ) and OER (overpotential of 252 mV at 10 mA cm −2 ). Particularly, for HER, it can maintain a consistent potential at 100 mA cm −2 for 100 h. Besides, for OER the generated surface roughness and larger surface area can enhance OER activity of the catalyst. When used as a bifunctional electrocatalyst for overall water splitting, it can achieve a current density of 10 mA cm −2 at a cell voltage of 1.699 V with excellent durability. This work provides a new strategy to fabricate three-dimensional heterostructured water-splitting electrocatalysts with large surface area.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2023
·
IF 7.2
Liping Zhang,Xiangchuan Zhao,Zhaoyun Chu,Qing Wang,Yue Cao,Jiao Li,Wu Lei,Jun Cao,Weimeng Si
Rational design of transition metal catalysts with robust and durable electrocatalytic activity for hydrogen evolution reactions (HER) is extremely important for renewable energy conversion and storage, as well as water splitting. Heteroatom doping has emerged as a feasible strategy for enhancing electrocatalytic activity. Here, cobalt nanoparticles (Co-NPs) were coated with nitrogen-doped carbon nanotubes (NCNTs) prepared via an in situ growth on accordion-like Ti 3 C 2 T x -MXene (Co-NCNT/Ti 3 C 2 T x ). Such an intriguing structure showed great features: abundant anchoring sites for NCNT in situ growth, intimate integration of Co-NPs and NCNTs, high-speed electron transfer between 1D NCNTs and 2D Ti 3 C 2 T x -MXenes, and a large number of effective catalytic active sites. This Co-NCNT/Ti 3 C 2 T x hybrid catalyst was demonstrated to possess excellent HER performance with low overpotential ( η 10 , 190 mV), small Tafel slope (78.4 mV dec −1 ), large electrochemically active surface area, and good long-term stability, thus outperforming many reported electrocatalysts . The present strategy provided a facile route for the design of transition metal HER catalysts with NCNT and MXene .
研究领域:
材料科学
·
能源化学
·
催化科学
✓ 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）