Carbon Erosion of a Bulk Nickel–Copper Alloy as an Effective Tool to Synthesize Carbon Nanofibers from Hydrocarbons

Abstract

Abstract Carbon erosion of bulk metals and alloys in a carbon-containing atmosphere can be used as an effective tool for the targeted synthesis of carbon nanomaterials. In this study, a set of bulk Ni 0.89 Cu 0.11 (11 at % Cu) alloys has been synthesized by the mechanochemical alloying of metal powders in an Activator 2S planetary mill. The synthesized samples have been studied as precursors of catalyst for the synthesis of carbon nanofibers (CNFs) from ethylene at 550°C. The effect of the activation time on the particle morphology and phase composition of the alloys, the kinetics of growth, and the carbon product yield in C 2 H 4 decomposition has been studied. For the most active samples, the CNF yield has exceeded 100 g/g cat within 30 min of reaction. The early stage of carbon erosion of a bulk Ni 0.89 Cu 0.11 alloy has been studied by electron microscopy methods. It has been found that the nucleation of carbon fiber growth active sites occurs during a short-term contact of the sample with the reaction mixture (less than 1 min); the complete disintegration of the alloy is observed in a few minutes. The carbon product is represented by nanofibers having a submicrometer diameter and characterized by a dense “stacked” and coaxial-conical packing of graphene layers. The material has a developed specific surface area (140–170 m 2 /g) and a low bulk density (less than 30 g/L).