Carbon Nano-onions: Potassium Intercalation and Reductive Covalent Functionalization

Abstract

Herein we report the synthesis of covalently functionalized carbon nano-onions (CNOs) via a reductive approach using unprecedented alkali-metal CNO intercalation compounds. For the first time, an in situ Raman study of the controlled intercalation process with potassium has been carried out revealing a Fano resonance in highly doped CNOs. The intercalation was further confirmed by electron energy loss spectroscopy and X-ray diffraction. Moreover, the experimental results have been rationalized with DFT calculations. Covalently functionalized CNO derivatives were synthesized by using phenyl iodide and n -hexyl iodide as electrophiles in model nucleophilic substitution reactions. The functionalized CNOs were exhaustively characterized by statistical Raman spectroscopy, thermogravimetric analysis coupled with gas chromatography and mass spectrometry, dynamic light scattering, UV–vis, and ATR-FTIR spectroscopies. This work provides important insights into the understanding of the basic principles of reductive CNOs functionalization and will pave the way for the use of CNOs in a wide range of potential applications, such as energy storage, photovoltaics, or molecular electronics.

Simulation of multi-shell fullerenes using Machine-Learning Gaussian Approximation Potential

“…The inter-layer separation between the outermost concentric shell showed a consistent value around 2.87 Å for all the models. This value is less than the interlayer separation observed in pristine Carbon nano-onions (≈ 3.5 Å) [51][52][53]. In the animation for the formation of BO 300 and BO 1374 provided in the supplemental material [22], the path of buckyonion formation brings about FIG.…”

Raman signatures of detonation soot

“…Spectral artifacts did occur at high laser powers. Ten spots on the T A B L E 1 Summary of the explosives used, the chemical formula, and the type of carbon found in each soot Explosive Chemical formula Carbon form UFTATB [25] C 6 H 6 N 6 O 6 Amorphous [11,14,[26][27][28] / weakly graphitic [12,[29][30][31] TATB [25] C 6 H 6 N 6 O 6 Amorphous [11,14,[26][27][28] / weakly graphitic [12,[29][30][31] HMX [32] C 4 H 8 N 8 O 8 Amorphous [11,14,[26][27][28] / weakly graphitic/ graphite sheets [12,[29][30][31] / graphite fibers [33,34] / diamond [35,36] DNTF [37] C 6 N 8 O 8 Carbon onions [38][39][40] HNS IV [41] C 14 H 6 N 6 O 12 Graphite fibers [33,34] Comp B [32] 60% C 3 H 6 N 6 O 6 40% C 7 H 5 N 3 O 6 nanodiamonds [35,36] LLM-105 [42] C 4 H 4 N 6 O 5 Amorphous ...…”

Zero-Dimensional Carbon Nanomaterials for Fluorescent Sensing and Imaging

“…49 Covalent compounding or tail functionalization with other materials can improve the properties of CNOs so that they are suitable for fluorescent sensing applications. 50 NDs are often regarded as a 3D CNMs because they have a 3D diamond-like structure. 44 However, NDs smaller than 100 nm can be regarded as a 0D CNMs, in which the fluorescence emission mainly originates from electron-rich defects in vacancies.…”

“…Although pristine CNOs do not emit any fluorescence, they exhibit a low density and toxicity and a high cellular compatibility and absorptivity . Covalent compounding or tail functionalization with other materials can improve the properties of CNOs so that they are suitable for fluorescent sensing applications . NDs are often regarded as a 3D CNMs because they have a 3D diamond-like structure .…”