Metal dusting as a key route to produce functionalized carbon nanofibers

https://doi.org/10.1007/s11144-022-02169-y

The present paper reports a new method of producing N-doped carbon nanofibers via metal dusting of a ternary NiMoW alloy in the atmosphere containing C2HCl3 and CH3CN vapors at 600 °C. The initial alloy was prepared by a co-precipitation technique. The carbon deposition was monitored gravimetrically. The early stages of the metal dusting process were studied in detail using scanning and transmission electron microscopies. It was established that the rapid disintegration of the microdispersed NiMoW alloy with the formation of nanosized particles catalyzing the growth of carbon filaments occurs within the first 5 min of the reaction. The presence of C2HCl3 vapors in the reaction medium was shown to be the urgent condition to provide efficient metal dusting. The effect of the CH3CN concentration in the trichloroethylene-containing reaction mixture on the carbon deposition is investigated. As observed, the CH3CN content noticeable affects the carbon yield (after 2 h of reaction). The dome-shaped dependence of carbon yield reaches its maximal value of ~ 200 g/g(cat) at a CH3CN concentration of 33 vol%. According to X-ray photoelectron spectroscopy, the obtained carbon filaments are functionalized with Cl (0.1–1.2 wt%), O (3–6 wt%), and N (0.5–1.3 wt%). The prepared carbon filaments possess a segmented secondary structure, which is typical for carbon nanomaterials derived via catalytic decomposition of chlorine-substituted hydrocarbons. Low-temperature nitrogen adsorption measurement revealed that the specific surface area of the N-containing samples varies in a range from 370 to 550 m2/g.