Mechanism study of metallic chromium and iron effects on the catalytic gasification reactivity of coke via experiments combined with density functional theory

To clarify the catalytic gasification mechanisms of metallic chromium and iron during prereduction and smelting reactions in submerged arc furnaces (SAFs), non-isothermal thermogravimetry and density functional theory (DFT) were employed to investigate the catalytic gasification characteristics, reaction kinetics, and CO2 interaction mechanisms on Cr(110) and Fe(110) surfaces. Both metallic chromium and iron shifted the carbon conversion curve to lower temperatures; these results indicated a catalytic effect and enhanced gasification reactivity. Kinetic analysis demonstrated that the random pore model (RPM) provided a better fit for describing the catalytic gasification process than the volumetric model (VM) and unreacted core model (URCM). DFT calculations revealed that the orbital energies of chemisorbed CO2 on the Cr(110) and Fe(110) surfaces shifted below the Fermi level; combined with the analysis of microstructure and charge transfer, this indicated that CO2 molecules exhibit a stronger interaction ability with the Cr(110) and Fe(110) surfaces and are effectively activated on these surfaces.