Enhancing CO oxidation stability of Ru/CeO2 catalysts via precursor phase transformation-induced strong metal-support interaction

In heterogeneous catalysis, achieving well-dispersed and highly active noble metal/support catalysts through strong metal-support interaction (SMSI) remains a key challenge. Conventional SMSI generation via high-temperature reduction or oxidation often leads to noble metal nanoparticles (NPs) agglomeration, compromising catalytic performance. In this work, we construct SMSI in a Ru/CeO 2 -S catalyst through phase transformation of a Ru 4 + /Ce-precursor (Ce(OH)CO 3 ) during high-temperature reduction, effectively preventing Ru NP sintering. The introduction of SMSI leads to Ru NPs being encapsulated by a CeO 2 layer, enhancing stability. We systematically investigate the SMSI formation mechanism and its influencing factors, such as the geometric coating degree of the Ru surface, oxygen vacancy concentration, and CO adsorption behavior. Compared to the conventional Ru/CeO 2 catalyst synthesized via impregnation (Ru/CeO 2 -T), the Ru/CeO 2 -S catalyst exhibits superior sintering resistance and stability for CO oxidation. Notably, it maintains its initial catalytic performance even after calcination at 700 °C in air, attributed to the enhanced SMSI effect. This work offers a strategic approach for designing stable, high-performance Ce-based noble metal catalysts. • Utilizing the Ce(OH)CO 3 -to-CeO 2 phase transformation to induce SMSI between CeO 2 and Ru nanoparticles (NPs). • Ru/CeO 2 -S exhibited a characteristic SMSI encapsulation structure, where Ru NPs were partially covered by a CeO 2 layer. • Even after calcination at 700 ℃ in air, Ru/CeO 2 -S retained its initial catalytic performance for CO oxidation. • The SMSI formation mechanism was elucidated by systematic analysis of CeO 2 support evolution during phase transformation.