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

Sulfur hexafluoride (SF) 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 SF degradation. The results showed that the performance of Mn-based composites with different oxidation states in the degradation of SF had an obvious hierarchy: SiC-Mn(0) > SiC-MnO(II) > SiC-MnO(III) > SiC-MnO(IV). Among them, SiC-Mn composites with Mn monomers as active centers reach a degradation capacity of 62.27 mL g 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 SF. This study emphasizes the importance of Mn oxidation states in determining the catalytic efficiency of Mn-based composites for SF degradation.