STRUCTURE OF CARBON NANOPARTICLES SYNTHESIZED BY ADIABATIC COMPRESSION OF ACETYLENE AND THEIR USE IN SUPERCAPACITORS
The work reports the study of the structure of carbon nanoparticles prepared by pyrolysis of helium-diluted acetylene under adiabatic compression in a piston reactor. At a pushing gas pressure of 0.5 MPa, 0.7 MPa, and 0.9 MPa the reaction gas heated to a temperature of 400° C, 600° C, and 750° C. By transmission electron microscopy it is found that carbon nanoparticles have a spherical form and their size varies from 20 nm to 60 nm. The structural features of carbon nanoparticles are determined from the Xray photoelectron spectroscopy data and the analysis of near-edge Xray absorption fine structure. Carbon nanoparticles prepared at a pushing gas pressure of 0.5 MPa have an amorphous structure and consist of hydrogenated carbon with an impurity of polycyclic aromatic fragments. At a stronger compression ratio, carbon nanoparticles with a layered structure consisting of mainly sp <sup>2</sup> hybridized carbon atoms form. The capacitance properties and electrochemical impedance of electrodes based on carbon nanoparticles in supercapacitors are compared.