To Promote Ozone Catalytic Decomposition by Fabricating Manganese Vacancies in ε-MnO₂ Catalyst via Selective Dissolution of Mn-Li Precursors

ε-MnO₂ catalysts with Mn vacancies and appropriate Li⁺ were designed with the help of density functional theory calculations (DFT) and prepared by a novel selective dissolution strategy. Their physiochemical properties were characterized and catalytic activity for ozone decomposition evaluated. DFT calculations showed that Mn vacancies and appropriate amounts of Li⁺ in ε-MnO₂ facilitated the formation of oxygen vacancies, decreased adsorption ability for H₂O and O₂, and maintained high adsorption ability for O₃ on these oxygen vacancies. Characterization results showed that preparing ε-MnO₂ by selective dissolution of Mn-Li precursors with 0.5 M HCl produced more Mn vacancies, and, thus, weaker crystallinity, larger specific surface area, superior reducibility, better oxygen storage capacity, and higher oxygen vacancies. This catalyst exhibited excellent activity and stability for ozone decomposition. Furthermore, a possible mechanism for ozone decomposition by the synergy of Li⁺, Mn vacancies, and oxygen vacancies in ε-MnO₂ was proposed.