Ti₃C₂-induced interface reconstruction of CeO₂ and in-situ derived TiO₂ boosting electron transfer and oxygen...

CeO₂-based catalysts have been employed in soot oxidation in diesel engine exhaust owing to their excellent oxygen storage and release capacity derived from Ce³⁺/Ce⁴⁺ redox cycle. However, CeO₂ still suffers from high reaction temperature limitation for soot oxidation, which seriously degrades its catalytic activity and reusability. Since soot oxidation degree strongly depends on active oxygen species and contact area, this study introduced Ti₃C₂ into CeO₂ to construct CeO₂-Ti₃C₂ with multiple heterojunctions, thereby enhancing CeO₂ electron migration to form appropriate quantity of oxygen vacancies on the surface. The results indicated that CeO₂/Ti₃C₂ construction induced TiO₂ derivation and formed Schottky heterojunctions including TiO₂/Ti₃C₂ and CeO₂/Ti₃C₂, which increased interfacial electron transfer paths for effective active oxygen species generation. Among synthesized catalysts, CeO₂/Ti₃C₂-12 exhibited a light-off temperature (T₁₀, 242 °C) and half-conversion temperature (T₅₀, 410 °C). Compared with the T₁₀ and T₅₀ values of CeO₂ in this study and other Ce-based catalysts documented in the literature, those of CeO₂/Ti₃C₂-12 were respectively reduced by 83 °C and 38 °C, demonstrating a remarkable low-temperature activity advantage. Such a result is attributed to Ti₃C₂-induced CeO₂ interface restructuring and lowered oxygen vacancies formation energy, which enhanced interfacial electron transfer thereby accelerated soot oxidation. This study proposes a facile and efficient CeO₂ interface reconstruction strategy to develop superior catalysts for soot oxidation and contribute to meeting China National Emission Standard VI for diesel engines.