Nanosize Control on Porous β-MnO₂ and Their Catalytic Activity in CO Oxidation and N₂O Decomposition.

A major challenge in the synthesis of porous metal oxides is the control of pore size and/or wall thickness that may affect the performance of these materials. Herein, nanoporous β-MnO₂ samples were prepared using different hard templates, e.g., ordered mesoporous silica SBA-15 and KIT-6, disordered mesoporous silica, and colloidal silica. These samples were characterized by Powder X-Ray Diffraction (PXRD), Transmission Electron Microscopy (TEM), and N₂ adsorption-desorption. The pore size distribution of β-MnO₂ was tuned by the different hard templates and their preparation details. Catalytic activities in CO oxidation and N₂O decomposition were tested and the mesoporous β-MnO₂ samples demonstrated superior catalytic activities compared with their bulk counterpart.