Manganese-based layered double hydroxide nanoparticles as highly efficient ozone decomposition catalysts with tunable valence state

Manganese oxides are well explored effective ozone decomposition catalysts, but the accumulation of oxygen trapped on their surfaces and high valence state restrict their catalyst efficiency. Herein, we report manganese based layered double hydroxide (LDH) catalysts with different average oxidation states (AOS) of Mn. MgMnAl-LDH catalysts show large specific surface area, abundant oxygen vacancies, stable structure and excellent catalytic ozone decomposition performance. The valence state of Mn can be tuned by adjusting the metallic element ratio in the LDH matrix, and a catalyst with AOS of only 2.3 is acquired. The impacts of the valence states of Mn on the catalytic ozone decomposition process were further studied by density functional theory (DFT) calculations. It is found that the Mn2+ facilitates the desorption of generated oxygen on the surface of LDHs, while Mn3+ and Mn4+ contribute to the dissociation of adsorbed ozone.