Surface structure effects in nanocrystal MnO2 and Ag/MnO2 catalytic oxidation of CO

Pure-phase α-MnO2 and β-MnO2 nanowires/nanorods were synthesized through an easy solution-based hydrothermal method, and the effect of the manganese dioxide phase on the activity of MnO2 and Ag/MnO2 for the oxidation of CO was investigated. MnO2 is an effective catalyst in CO oxidation, and its activity depends on the crystal phase of MnO2. α-MnO2 exhibits a higher activity than β-MnO2, because the α-MnO2 nanowires can be reduced more easily than the β-MnO2 nanorods. Moreover, when Ag was introduced to MnO2, a strong interaction occurred between Ag and MnO2. The catalytic activity clearly correlates with this interaction, which is determined by crystal phase and surface structure.