Revealing the Jahn–Teller Mitigating Complexity of Se-Anchored Mn Oxides for Superior SO₂ Resistance in Gaseous Molecular Oxygen Activation

Manganese oxides have emerged as promising catalysts for the low-temperature activation of molecular oxygen (O2), crucial for the catalytic oxidation and removal of gaseous pollutants. However, the undesired Jahn–Teller (J-T) effects associated with the Mniv/Mniii redox couple, particularly under SO2 poisoning, led to the effectiveness of Mn oxides in applications. Herein, we construct a highly covalent Seiv-O-Mniii structure via the introduction of selenium into α-MnO2. Such a structure features high-valence Seiv anchored on the oxygen-terminated (110) plane of α-MnO2, facilitates the generation of more active oxygen species, and maintains the continuous cycling of oxygen-linked Mniv/Mniii. Such dynamics are pivotal for stabilizing manganese activation and mitigating the J-T effect. Through a combination of experimental investigations and theoretical calculations, we demonstrate that the Seiv-O-Mniii configuration, characterized by a high degree of Mn–O hybridization, significantly enhances CO oxidation, NH3 oxidation, and elemental mercury (Hg0) removal performances, and exhibits resistance to SO2. This study paves the way for the development of efficient low-temperature O2 activation processes for the removal of gaseous pollutants in real-world applications.