K⁺ doping Ce-Sm oxide catalysts on cordierite honeycomb ceramic substrate for soot catalytic combustion

Cerium samarium oxides catalysts with K⁺ doping on the wall surface of cordierite honeycomb ceramics were preparation by sol–gel and dipping processes. Scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and Fourier transform-infrared spectroscopy were used to characterize the structural morphology and phase compositions. Through XPS analysis and H₂-TPR measurement of monolithic catalyst, it is found that potassium ions improve the oxygen mobility in CeO₂ lattice and form surface active oxygen, increase the amount of oxygen adsorbed on the surface and improve the oxidation–reduction capacity. The catalytic combustion research demonstrates that T₁₀, T₅₀ and T_m in samples (Ce/Sm-0 K, Ce/Sm-0.3 K, Ce/Sm-0.5 K and Ce/Sm-0.7 K) decrease significantly compared with the blank reference (Cordierite). And the optimized sample Ce/Sm-0.5 K possess the lowest T₁₀ (389.6 °C), the lowest T₅₀ (425.5 °C), and the lowest T_m (419 °C) in comparison with other samples. The cycle stability investigation reveals that sample Ce/Sm-0.5 K has excellent structural stability and stable catalytic performance, which has potential application in soot catalytic combustion field.