Effects of Cobalt-Doped Modification on the Catalytic Reduction of SO2 with CO over an Iron/BFS Catalyst

Abstract

To realize high-value sulfur recovery and decrease the reaction temperature, a cobalt-doped modified iron-based catalyst was prepared from blast furnace slag (BFS), which is a byproduct of steelmaking. The effects of the carrier and active components on the catalytic reduction performance were studied, and the mechanism of the optimized modification to promote catalytic reduction was explored. When the mass ratio of cobalt tetroxide, ferric oxide, and the carrier in the catalyst was 4:15:81, the temperature required for the reaction was reduced to 400 °C, and the SO2 conversion rate and average sulfur yield were maintained above 90 and 80% within 2 h, respectively. The results of an in situ diffuse reflectance infrared Fourier-transform spectroscopy experiment and density functional theory calculations revealed that the catalytic mechanism followed both the redox route and the cosine intermediate route. The cobalt-doped modification increased the intermediate acidic sites on the catalyst surface and widened the adsorption temperature range of the catalyst, thus positively promoting the catalytic reaction.