MnFeOx@TiO2 Nanocages for Selective Catalytic Reduction of NO with NH3 at Low Temperature

Based on Prussian blue analogues (PBAs), using the in situ self-assembly method, MnFeOx@TiO2 double-walled nanocages with a hollow and porous structure were constructed by annealing the core-shell structure of Mn-3[Fe(CN)(6)](2)center dot nH(2)O@Ti(OH)(4). Compared with the MnFeOx single-walled nanocages without the TiO2 shell, the MnFeOx@TiO2 double-walled nanocages exhibited a better catalytic performance in selective catalytic reduction (SCR) with NH3 at low temperatures, and the NO removal efficiency could reach 80% at 145-260 degrees C. Establishing the TiO2 shell layer could effectively improve the adsorption and activation performance of the reactants. Through a series of characterizations, it was confirmed that the MnFeOx@TiO2 double-walled nanocages possessed a large specific surface area, abundant structural defects, and oxygen vacancies. Besides, the MnFeOx@TiO2 catalyst had more Mn4+ species, higher Fe3+ species, more surface-adsorbed oxygen (O-a(ds)) species, and a strong interaction between MnOx, FeOx, and the TiO2 shell, which led to better catalytic activity. At the same time, the MnFeOx@TiO2 double-walled nanocages exhibited satisfactory thermal stability and better H2O resistance.