Chemistry Africa-A Journal of the Tunisian Chemical Society
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2021
·Vol. 5
·期 1
·79-87
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IF 0
Naz Farah,Ciprian Matteo,Luo Zhixiong,Yan Shilin,Iqbal Shahzad Zafar,Zhu Meifang,Chaemchuen Somboon,Verpoort Francis
The synthesis and use of MOF-derived Co/NCF (N-doped carbon framework) material as a heterogeneous catalyst for copolymers synthesis via ring-opening polymerization (ROP) are reported for the first time. The Co/NCF material is applied for the copolymerization of L -lactides (LA) and ε-caprolactone (ε-CL) as monomers via ROP in bulk without any solvent or co-catalyst. The as-prepared catalyst is characterized using XRD, TPD, XPS, SEM, and TEM analytical techniques. At the same time, 1 H and 13 C-NMR spectroscopy were used to analyze the microstructure of the copolymer confirming the random copolymer structure. The average r values calculated from the heterodiad analysis of the 1 H NMR, data were r LA = 0.96 and r CL = 0.93 and L value calculated from the triads analysis of 13 C NMR, data were L LA = 3.17 and L CL = 2.79, respectively. It has been observed that the melting temperature and glass transition temperature of the copolymer increases with higher LA content. The XRD and DSC analyses also confirmed that the as-synthesized copolymer possesses two phases corresponding to the polylactide and polycaprolactone, respectively. Additionally, the activity of Co/NCF is also compared with other Co-based heterogeneous catalysts to demonstrate its ability. Graphic Abstract
研究领域:
材料科学
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催化化学
✓ 已验证
DOI
INORGANIC CHEMISTRY COMMUNICATIONS
·
2025
·
IF 5.4
Junjie Ma,Wei Li,Xiaoqi Lan,Zheng Liu,Fenghai Zhou,Mingjun Lu,Guo-Cheng Han
The Na 3 V 2 (PO 4 ) 2 F 3 /Co/N-PC composite was prepared based on nitrogen-doped porous carbon materials containing cobalt (Co/N-PC), which is obtained through high-temperature pyrolysis of bimetallic Co/Zn-MOF. The electrochemical test results showed that the discharge specific capacity of Na 3 V 2 (PO 4 ) 2 F 3 /Co/N-PC composite was 126.66 mAh/g at 0.1C, an increase of 15.6 % compared with Na 3 V 2 (PO 4 ) 2 F 3 /N-PC(109.56 mAh/g). The capacity retention rate was 91.84 % after 100 cycles and the R SEI of the Na 3 V 2 (PO 4 ) 2 F 3 /Co/N-PC composite (48.62 Ω) outperforms that of the Na 3 V 2 (PO 4 ) 2 F 3 /N-PC composite (81.55 Ω). This work applied the metal/carbon hybrid materials obtained through high temperature pyrolysis of bimetallic organic frameworks were employed in sodium-ion batteries, thereby offering enhanced potential for the advancement of sodium-rich phosphoric acid modified materials.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
CARBON
·
2022
·
IF 11.307
Zhiqian Yao,Feng Liu,Suqiong Xu,Xianke Zhang,Chuicai Rong,Zuzhou Xiong,Jujun Yuan,Yi Yu,Xiurong Zhu,Huajun Yu
Prussian blue, a member of the metal-organic frameworks (MOFs), has attracted great interest in electromagnetic wave absorption due to its unique properties, such as multiple morphologies and tunable structures. In this paper, La 2 O 3 /Co@N-doped carbon nanotubes (La 2 O 3 /Co@NCNTs) composites were synthesized by thermal annealing La[Co(CN) 6 ]·5H 2 O Prussian blue analogue (LaCo-PBA) precursors under an Argon (Ar) atmosphere. The studies of electromagnetic wave absorption show that La 2 O 3 /Co@NCNTs demonstrated the minimum reflection loss (RL) of −53.40 dB with the effective absorption bandwidth (EAB) of 4.34 GHz at the thickness of 2.45 mm. These excellent microwave absorption properties are attributed to multiple loss mechanisms, including conduction loss , polarization loss, magnetic resonance loss, and eddy current loss . This study offers a new possibility for the design of multifaceted lightweight carbon-based microwave absorbing materials.
研究领域:
材料科学
·
电磁学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2025
·
IF 6.3
Xin Ling,Yihan Zhang,Yitong Zhou,Yu Wang,Yuqin Xiong,Yili Liu,Hui Pan,Wang Zhang,Di Zhang
The increasing demand for lightweight and efficient microwave absorbers has underscored the importance of simultaneously optimizing electromagnetic attenuation and impedance matching. Although MOF-derived carbon nanocomposites offer tunable conductivity and versatile microstructures, prior research has largely focused on single-structure modifications, overlooking the broader impact of microstructural configuration. In this study, we systematically engineered four distinct structural configurations, including solid, hollow, porous, and hollow-porous, within a unified ZIF-67-derived Co/N-doped carbon system. Comparative analysis reveals that hierarchical structure modulation plays a decisive role in balancing impedance matching and attenuation mechanisms. Specifically, the hollow-porous composite (HM-CoNC) achieves synergistic enhancement through multi-interface polarization, scattering, and conductive/magnetic losses, enabled by the integration of mesoporous, internal cavities, and uniformly dispersed Co nanoparticles. As a result, HM-CoNC exhibits a minimum reflection loss of -69.52 dB at 1.62 mm and an effective absorption bandwidth of 5.25 GHz at 1.69 mm, outperforming its structural counterparts. Radar cross-section simulations further validate its stealth potential with a 29.87 dB·m² reduction relative to the uncoated substrate. These findings provide valuable insight into the microstructure-performance relationship and highlight hierarchical engineering as an effective strategy for designing high-performance microwave absorbing materials.
研究领域:
材料科学
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纳米技术
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电磁学
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微波工程
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2024
·
IF 5.5
Rui Wang,Yixin Yan,Lu Wang,Xiaoya Kang,Shengtao Niu,Youzhi Wu,Fen Ran
Metal-organic framework draws widespread interest on account of its large specific surface areas, which could be employed as sacrificial templates to synthesize Co/N-doped carbon nanocubes. Herein, Ni-Co 3 ZnC is used as an additive for improving the electrical conductivity as well as lithium-storage performance of Co/N-doped carbon because of the conductivity and catalytic activity of metal nanoparticles . Co/N-doped carbon nanocubes and Co/N-doped carbon-Ni-Co 3 ZnC anode materials are prepared through one-step precipitation and high-temperature calcination methods. The lithium-storage capabilities of Co/N-doped carbon and Co/N-doped carbon-Ni-Co 3 ZnC are investigated. Co/N-doped carbon-Ni-Co 3 ZnC manifests good electrochemical performance at 2.0 A g −1 compared to Co/N-doped carbon. The initial reversible capacities of Co/N-doped carbon and Co/N-doped carbon-Ni-Co 3 ZnC are 877.4/548.4 and 1, 170.5/557.3 mAh g −1 , and the reversible capacities could be maintained at 152.6/152.4 and 276.8/276.5 mAh g −1 after 2, 000 cycles. The electrode kinetic results evidence that Ni-Co 3 ZnC could enhance the conductivity of Co/N-doped carbon. The data provide a theoretical basis for improving the lithium-storage performance of prevalent anode materials.
研究领域:
材料科学
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电化学
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能源存储
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2025
·
IF 21.1
Sijia Liu,Jiangjie Zhan,Changqing Yang,Chaohai Wei,Yun Hu
The photocatalytic cooperative hydrogen evolution and alcohol oxidation process for producing of two valuable products is highly attractive strategy, but optimizing active sites and constructing dual-function photocatalysts with high activity and selectivity remains challenging. In this study, dual active sites photocatalysts of Co/N-doped graphitic carbon nanocages (CoNC)/ZnIn 2 S 4 nanosheets (ZIS) were successfully prepared, where the Co atom anchoring on N-doped carbon (Co-N structure) and Co nanoparticles (Co NPs) encapsulating in layered graphitic carbons, resulting in the simultaneous photocatalytic hydrogen production and selective oxidation of benzyl alcohol to benzaldehyde. After regulating the active sites ratio of Co NPs/Co-N, the CoNC/ZIS exhibited an excellent hydrogen production rate (2334 μmol g⁻¹h⁻¹) and benzaldehyde production yield (2825 μmol g⁻¹h⁻¹), which were 9.0 times and 17.5 times than that of pure ZIS, respectively. The characterization results indicated that the Co-N structure served as electron-rich sites and Co NPs served as sites for dehydrogenation, promoting directed electron-hole migration and providing sufficient the optimum reaction sites for hydrogen evolution and benzyl alcohol oxidation. Furthermore, the CoNC optimized structure and interface environment of ZIS, by reducing the potential of the valence band edge and enhancing the adsorption energy for benzaldehyde, thereby effectively improving the selectivity for benzaldehyde (increased from 47.9 % to 99.2 %). Based on DFT calculations, that the synergy of interfacial Co-N structure and Co NPs played a critical role in the coupled photocatalytic system and enhanced photogenerated carrier utilization. This study suggests new avenues to the design of a dual-function photocatalyst for significantly improve the utilization efficiency of solar energy.
研究领域:
催化
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材料科学
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纳米技术
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物理化学
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化学工程
✓ 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）