Catalytic anisotropy induced by multi-particles for growth of carbon nanocoils

Zhao, Yuechao; Wang, Jianzhen; Huang, Hui; Zhang, Hao; Cong, Tianze; Zhang, Dongmei; Wen, Ningxuan; Zhang, Yifeng; Fan, Zeng; Pan, Lujun

doi:10.1016/j.carbon.2020.05.007

Cited by 39 publications

(8 citation statements)

References 59 publications

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“…Upon the onset of MDA reaction, the two peaks of Fe 2 O 3 in 4%-IWI vanish and four new diffraction peaks emerge at 2θ of 42.9°, 43.7°, 45.0°, and 45.9° (Figure b, green lines), which are attributed to the (1 2 1), (2 1 0), (1 0 3), and (2 1 1) facets of Fe 3 C (JCPDS: No. 075-0910), respectively. , Note that in 4%-IWI the diffraction peak of Fe 3 C (1 0 3) facet at 2θ of 45.0° overlaps with that of (8 0 4) facet of ZSM-5 (JCPDS No. 042-0023), leading to its higher peak intensity than the adjacent peak of ZSM-5 (0 10 0) facet at 2θ of 45.5°.…”

Section: Results and Discussionmentioning

confidence: 99%

Active Sites and Induction Period of Fe/ZSM-5 Catalyst in Methane Dehydroaromatization

Chen

Wang

et al. 2021

ACS Catal.

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Fe/ZSM-5 is a potential methane dehydroaromatization (MDA) catalyst in addition to Mo/ZSM-5. In this study, Fe/ZSM-5 catalysts are prepared via a grinding synthesis method (GSM) using Na2FeO4 as the iron precursor. Iron species in the obtained catalysts are presented mainly as isolated or low-polymerized sites in zeolite cationic exchange positions and pores/channels, generating strong metal–support interactions. These iron species are found to be highly resistant to the reduction and carburization of methane in the MDA reaction, which contradicts common Fe/ZSM-5 catalysts. The rapid formation of active iron suboxides (highly dispersed FeO, Fe3O4 or FeO x ) together with the fast generation of hydrocarbon pool species inside zeolite channels considerably shorten the induction period. Owing to the strong metal–support interaction, the formed iron suboxides could also withstand sintering/agglomeration and inhibit coke accumulation on the external catalyst surface during reaction. While for Fe/ZSM-5 catalysts prepared by the conventional impregnation method, the iron oxides remain principally at the external surface as big clusters/particles with weak metal–support interaction, which then undergo complete reduction and carburization during MDA reaction. The slow formation of active iron carbides and subsequent slow generation of hydrocarbon pool species result in a longer induction period. Moreover, complete dehydrogenation of methane takes place on the iron carbides at the outmost surface of the catalyst, causing massive coke accumulation. Hence, the shortened induction period together with higher coking resistance of GSM Fe/ZSM-5 provide more thought to the design of iron-based MDA catalysts.

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Section: Results and Discussionmentioning

confidence: 99%

Active Sites and Induction Period of Fe/ZSM-5 Catalyst in Methane Dehydroaromatization

Chen

Wang

et al. 2021

ACS Catal.

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“…Besides, the CVD technology was used to synthesize high-purity CNCs by using porous Fe 2 O 3 /SnO 2 nanoparticles as the catalyst. Specifically, the growth process was carried out at 710 °C for 180 min with the introduction of 350 and 30 sccm Ar and C 2 H 2 gases simultaneously [ 46 , 47 ]. After reaction, the CNCs were dispersed and washed by 68 wt% nitric acid and deionized (DI) water successively.…”

Section: Methodsmentioning

confidence: 99%

Structural Engineering of Hierarchical Aerogels Comprised of Multi-dimensional Gradient Carbon Nanoarchitectures for Highly Efficient Microwave Absorption

et al. 2021

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Recently, multilevel structural carbon aerogels are deemed as attractive candidates for microwave absorbing materials. Nevertheless, excessive stack and agglomeration for low-dimension carbon nanomaterials inducing impedance mismatch are significant challenges. Herein, the delicate “3D helix–2D sheet–1D fiber–0D dot” hierarchical aerogels have been successfully synthesized, for the first time, by sequential processes of hydrothermal self-assembly and in-situ chemical vapor deposition method. Particularly, the graphene sheets are uniformly intercalated by 3D helical carbon nanocoils, which give a feasible solution to the mentioned problem and endows the as-obtained aerogel with abundant porous structures and better dielectric properties. Moreover, by adjusting the content of 0D core–shell structured particles and the parameters for growth of the 1D carbon nanofibers, tunable electromagnetic properties and excellent impedance matching are achieved, which plays a vital role in the microwave absorption performance. As expected, the optimized aerogels harvest excellent performance, including broad effective bandwidth and strong reflection loss at low filling ratio and thin thickness. This work gives valuable guidance and inspiration for the design of hierarchical materials comprised of dimensional gradient structures, which holds great application potential for electromagnetic wave attenuation. "Image missing"

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“…Detailed procedures can be referred to the reported literature. [32][33] The as-prepared CNC was scrapped from the substrate and dispersed in 20 mL of water under ultrasonication. For the direct growth of Au NPs on the CNC, 1 mL of the CNC solution was added to 19 mL of water in a round-bottomed flask and stirred at 90 °C.…”

Section: Methodsmentioning

confidence: 99%

2D Wavelength‐Polarization Dispersive Microspectroscope Based on a Hybrid Plasmonic Helical Nanostructure

Sun

Chen

Zhang

et al. 2022

Adv Materials Technologies

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Microspectrometer features remarkable portability and integration and is prospected to provide quick detection tools to daily life and revolutionize research techniques. Due to the extremely finite footprint, microspectrometer can hardly analyze the polarization feature by placing a polarizer in the optical path as conventional spectrometers. Here, a novel 2D wavelength‐polarization dispersive microspectroscope based on a carbon nanocoil with plasmonic Au nanoparticles (Au/CNC) as a dispersive component is demonstrated. The unique 2D dispersion properties of Au/CNC are examined by microspectroscopic and Fourier spatial microscopic exploration. Au/CNC disperses light as wavelength to bands of different diffraction orders like a grating along the coil axis. The wavelength of the incident light can be obtained from the location of the signal lines in a relatively large visible‐near‐infrared wavelength range. Perpendicular to the coil axis, incident light is dispersed as polarization with bright and dark areas. Therefore, the left‐ and right‐circularly polarized light can be distinguished, and polarization orientation of linearly polarized light can be obtained. This effect provides a powerful microspectrometer that simultaneously analyzes wavelength and polarization features. Moreover, this potent tool can further evolve new revolutionary techniques via integration with other systems.

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Catalytic anisotropy induced by multi-particles for growth of carbon nanocoils

Cited by 39 publications

References 59 publications

Active Sites and Induction Period of Fe/ZSM-5 Catalyst in Methane Dehydroaromatization

Active Sites and Induction Period of Fe/ZSM-5 Catalyst in Methane Dehydroaromatization

Structural Engineering of Hierarchical Aerogels Comprised of Multi-dimensional Gradient Carbon Nanoarchitectures for Highly Efficient Microwave Absorption

2D Wavelength‐Polarization Dispersive Microspectroscope Based on a Hybrid Plasmonic Helical Nanostructure

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