Synthesis, characterization, and catalytic application of titanium–cryptomelane nanorods/fibers

One-dimensional titanium–cryptomelane manganese oxide nanomaterials were successfully synthesized and characterized by TEM, SEM, XRD, XPS, and BET surface area and pore size distribution measurements. Nanosizes of titanium–cryptomelane nanomaterials were effectively controlled by the synthesis routes, and uniform nanorods were obtained by the reflux method and nanofibers by the hydrothermal one. HRTEM, XRD and N2 adsorption–desorption analyses revealed that the materials exhibited the cryptomelane crystal structure with the pore diameters of about 0.5 nm. XPS studies demonstrated that Ti4+ cations of titanium–cryptomelane materials were located at the octahedral coordinated environments, and that the average oxidation states of manganese species were about 3.9. These materials showed high catalytic activities toward CO oxidation at ambient temperature, and catalytic behaviors showed a correlation with the surface area, the morphology and the titanium content.