Size-selected polyynes synthesised by submerged arc discharge in water

Abstract

Polyynes, linear sp-carbon chains of finite length, can be synthesised by submerged arc discharge in liquid, which so far, has been mainly exploited in organic solvents.In this work, we investigated the technique in water as a cheap and non-toxic solvent to produce polyynes. After optimisation of the process parameters, hydrogen-terminated polyynes (CnH2: n=6-16) were identified by high-performance liquid chromatography with the support of theoretical calculations. Size-selected polyynes were separately analysed by surface-enhanced Raman spectroscopy allowing to assign the bands of mixed polyynes solution to specific wire lengths. Stabilisation strategies for hydrogen-capped polyynes were also studied, obtaining promising results.

In situ synthesis of polyynes in a polymer matrix via pulsed laser ablation in a liquid

“…the number of carbon atoms) ranging from 6 to 10 in agreement with previous studies. 19,45,46 Longer polyynes may be present but are hardly detectable due to their low concentration, which results in a weak signal also partially covered by the PVA peak. In fact, for PVA concentration exceeding 0.5 wt%, the strong PVA peak makes it difficult to identify the presence of polyyne.…”

“…After 3 weeks, the decomposition of polyynes in Ag/PVA solution, evaluated considering the integrated area of the SERS signal in sp-carbon range, is about 60%, which is anyway strongly reduced with respect to the case of polyynes in the aqueous Ag colloid, whose area decrease after 3 weeks is 95% (as reported in ref. 19). In the spectra of solid nanocomposites, we observe after 1 week a decrease of the intensity of the polyynic SERS bands of the order of 50% but then, the spectrum does not substantially change up to 11 months.…”

“…[16][17][18] However, the use of water in SADL was recently shown to achieve polyynes of up to 16 carbon atoms or to obtain polyynes by collecting and condensing the gas generated by arc discharge. 19,20 To fully take advantage of the properties of polyynes, the availability of a stable material under ambient conditions is required. The stability of sp-carbon atomic chains is not a trivial issue.…”

Solvent-dependent termination, size and stability in polyynes synthesis by laser ablation in liquids

“…Time Dependent Density Functional Theory (TD-DFT) calculations were carried for the prediction of the vibronic spectra at CAM-B3LYP/cc-pVTZ level of theory, while PBE0/cc-pVTZ calculations have been used for the computation of the Raman spectra. Based on TD-DFT calculations, Huang-Rys factors and vibronic spectra have been computed by home-made programs 32,33 . The computed vibrational frequencies were multiplied by a scale factor of 0.961 in the comparison with experimental spectra 34 .…”

Purification of Carbon-Based Magnetic Nanoparticles (CMNs) Produced by Submerged Arc Discharge in Liquid Ethanol/Ethylenediamine

“…The other compound containing iron with magnetic properties is the iron oxide of Fe3O4, which has been proven to be biocompatible in bioapplications, especially when combined with carbon material (Fang, Cheng, Zhang, Zhang, & Keidar, 2018;Wang et al, 2018). Some methods that have been used to synthesize iron oxide/carbon (Fe3O4/C)-based materials include the solvothermal method (Ren, Lin, Meng, & Zhang, 2019;Vinodhkumar et al, 2020), the hydrothermal method (Li et al, 2019), and the arc discharge method (Peggiani et al, 2020;Saraswati, Retnosari, Hayati, Amalia, & Hastuti, 2018;Zhao et al, 2019). In general, the arc discharge method can be performed in both a low-pressure chamber and in a liquid medium.…”