Synthesis and characterization of potassium titanates used as soot oxidation catalyst in diesel exhaust

Potassium titanates of different K/Ti ratio were synthesized by solid-phase method using TiO₂ and K₂CO₃ as raw materials. The catalysts were characterized by SEM and XRD, and their catalytic activities were evaluated by soot oxidation reaction using TPR system. The results showed that K₂Ti₂O₅ had good crystallinity at 850℃, and the synthesized K₂Ti₂O₅ almost had the same degree of crystallinity using CH₃COOK、KNO₃ and K₂CO₃ as precursors of K, respectively；K₂Ti₂O₅ of high K/Ti ratio can significantly reduce the soot oxidation temperature, the lowest ignition temperature was 280℃, and K₂Ti₂O₅ had higher catalytic activity than the Pt-impregnated catalyst in soot oxidation.