Regulatory Evolution of δ-MnO2 Active Sites Enhances Ozone Decomposition

Abstract Ozone (O3) pollution arising from rapid urbanization poses a significant threat to both the air quality and human health. Manganese dioxide, a widely studied material, typically exhibits limited performance due to the occupation of oxygen vacancy (Vo) sites by water and reaction intermediates. In this work, we tailored the surface coordination environment via heat treatment, yielding a series of catalysts with varying numbers of hydroxyl groups and Vo sites. Characterization results revealed that surface hydroxyl groups not only serve as supplementary reactive sites but also modulate the electronic properties of Vo sites, thereby effectively lowering the desorption energy of the intermediate species. Notably, superior catalytic activity was achieved even at a relatively low density of Vo sites. In situ DRIFTs were employed to systematically monitor the reaction intermediates and track the reaction evolution. Complementary DFT calculations further elucidated the accompanying changes in the electronic structure and reaction pathways. This work deepens the mechanistic understanding of catalytic O3 decomposition, offers valuable guidance for rational structural design, and facilitates its practical applications.