Diesel soot oxidation over potassium-promoted urchin-structured NiO-NiCo2O4 catalyst

Catalytic oxidation is an effective strategy to eliminate soot emitted from diesel engines. However, the insufficient contact sites and low intrinsic activity of catalysts severely limit the development of the technique. Herein, we designed and prepared a potassium-promoted NiO-NiCo2O4 composite endowed with an urchin-like structure (K/NiO-NiCo2O4 US), which displayed high catalytic activity for soot oxidation with temperatures of soot conversion at 10% (T10) and 50% (T50) as low as 307 °C and 347 °C, respectively. The enhanced performance was unveiled based on a series of characterization results. On one hand, the urchin-like structure increased the contact efficiency between the soot and the catalyst. On the other hand, the loading of potassium generated more Co3+ species and active oxygen species, improving the oxidation ability.