The role of manganese oxidation states in the performance of SiC-supported composites toward SF6 degradation

Abstract

Sulfur hexafluoride (SF₆) is a potent greenhouse gas with a significant impact on the environment and there is a need to develop effective strategies toward its degradation. In this study, a series of composites with Mn-based metal active centers were synthesized using a simple and efficient milling method with SiC as the carrier to determine the effect of different oxidation states of Mn on SF₆ degradation. The results showed that the performance of Mn-based composites with different oxidation states in the degradation of SF₆ had an obvious hierarchy: SiC–Mn(0) > SiC–MnO(II) > SiC–Mn₂O₃(III) > SiC–MnO₂(IV). Among them, SiC–Mn composites with Mn monomers as active centers reach a degradation capacity of 62.27 mL g⁻¹ at 600 °C. This performance trend is attributed to the stronger electron-supplying ability of the Mn species with lower valency, which enhances the cleavage of the strong S–F bonds in SF₆. This study emphasizes the importance of Mn oxidation states in determining the catalytic efficiency of Mn-based composites for SF₆ degradation.