RESUMO
To understand the physical phase structural variation and activation pathway of the active component during the catalytic reduction of pyrite (FeS2)-based catalysts, multiple methods, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and high-temperature in situ XRD, were applied to characterize the catalyst and reaction process. The reaction mechanism was simulated and verified using density functional theory. The results indicated that pyrite-based catalysts promote the CO reduction of SO2 to S through the dynamic transformation of three phases (FeS2, Fe7S8, and FeS), in which S-vacancy formation is the most important step. As the critical temperature for the reaction of FeS2 and CO was initiated at approximately 525 °C, the active component's physical phase structure and activation pathway could be controlled by adjusting the temperature.
