Formation of Ni/C based polyacrylonitrile nanocomposites under IR-radiation

Abstract

The work deals with obtaining nickel metal-carbon nanocomposites based on IR-pyrolyzed polyacrylonitrile and nickel chloride hexahydrate and a study of the structural characteristics of the synthesized material. Nanocomposites have been prepared under IR-based precursor pyrolysis of polyacrylonitrile (PAN) and nickel chloride hexahydrate (NiCl2·6H2O). Pyrolysis has been carried out in the 150–700°C temperature range. The grown nanocomposites are a two-phase system of the carbon matrix formed during carbonization of PAN and distributed in the nickel nanoparticles (nickel oxide). The average size of the nanoparticles in the nanocomposite was 15–25nm. The effect of IR precursor pyrolysis temperature on the size of the nickel nanoparticles has been studied.We have determined that the size distribution of nickel nanoparticles is determined by the temperature of nanocomposite synthesis. While the temperature increases the prevailing average particle size of the metal increases and the distribution is blurred and shifts towards larger sizes.By calculating the total Gibbs energy of possible reduction reactions of nickel chloride and oxide pyrolysis PAN products we have shown the possibility of the formation of nanocomposites comprising nickel oxide nanoparticles which can be reduced to zero-valence state at higher temperature IR heating (more than 5000°C).