A nanorod-like KTi8O16 catalyst for soot combustion

A nanorod-like KTi8O16 catalyst was successfully prepared by combustion method and applied for removing hazardous diesel soot. The cryptomelane structure of KTi8O16 is confirmed by X-ray powder diffraction (XRD). The straight and smooth crystalline nanorods with the diameter of 180 nm are identified by transmission electron microscopy (TEM) and (200) facet is observed to be preferentially exposed. K cations are not freely present in cryptomelane structure of KTi8O16 derived from X-ray absorption fine-structure (XAFS) results, possibly due to the confinement or interaction of K with Ti element. By temperature-programmed oxidation (TPO) experiments, its catalytic soot combustion performance was evaluated, with T 10 and T m of 435°C and 511°C, which are decreased by 19°C and 45°C respectively compared with pure anatase TiO2. K+ species are deduced to serve as the active sites in the catalytic soot oxidation reaction, which are confined in the channels of the nanorod-like KTi8O16.