The Role of Manganese Oxidation State in SF6 Degradation Performance of SiC-Supported Composites

Sulfur hexafluoride (SF6) is a potent greenhouse gas with a significant impact on the environment and there is a need to develop effective degradation strategies. 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 valence states of Mn on SF6 degradation. The results showed that the degradation performance of SF6 by Mn-based composites with different valence states had an obvious hierarchy: SiC-Mn(0)>SiC-MnO(II)>SiC-Mn2O3(III)>SiC-MnO₂(IV). Among them, the SiC-Mn composites with Mn monomers as active centers reach 62.27 mL/g at 600 °C. This performance trend is attributed to the stronger electron supplying ability of the lower valence Mn species, which enhances the cleavage of the strong S-F bonds in SF6. This study emphasizes the importance of the valence states of Mn in determining the catalytic efficiency of Mn-based composites for SF6 degradation.