Influence of alkali metal Na on coal-based soot production.

• Cracking experiments were performed with pyrene instead of coal tar. The reactants are simple and the process can be controlled. • The effect of Na on the soot formation process was analyzed by a combination of experiments and simulations. • Na promoted the oxidation of soot, promoted the formation of five-membered rings in the microchip layer, and increased the curvature of the microchip layer. This work aims to investigate the effects of Na on the characteristics of coal-derived soot. Soot, which has long been regarded as an unwelcome source of air pollution, has been classified as a pollutant. However, with the proposed clean and efficient utilization of coal, soot has been found to be effectively inhibited by adding metal catalysts and changing the reaction environment, and it can even realize the transformation of pollutants to functional materials. To understand the effect on physiochemical properties, pyrene was used as a coal tar substitute, and the structural transformation of soot was thoroughly investigated by DFT calculation method in combination with elemental analysis, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The presence of Na changed the π electron distribution of benzene ring, promoted the dehydrogenation condensation and oxidation exfoliation of the surface microchip layer, and accelerated the condensation of PAHs and the formation of five-membered ring in the microchip layer. Na participates in the oxidation and growth process of soot, which can regulate the micromorphology of soot. With the participation of Na, the diameter of soot particles decreases, the microcrystal length and curvature become larger, and the internal holes increase. [ABSTRACT FROM AUTHOR]