Dynamic Metal Encapsulation in a Pt/TiO x system Regulated by Pt-Assisted TiO2 Amorphization

Strong metal–support interaction (SMSI) plays an important role in heterogeneous catalysis, but remains poorly understood, particularly on the origin of SMSI under an oxidative atmosphere. Hereby grand canonical structure exploration of over 4 million bulk PtTi alloys and Pt or PtTi-supported Ti oxide (TiOx) surface structure candidates, we resolve the Pt/TiOx system, a text-book example of SMSI, under both reductive and oxidative conditions: it experiences an encapsulation─deep encapsulation─decapsulation dynamic reconstruction under a sequence of H2 reduction─O2 oxidation─H2 plus O2 redox thermal treatment. The whole process was kinetically simulated by long-time (69 ns) molecular dynamics simulations, revealing in detail how a 3 nm Pt nanoparticle undergoes nonclassical SMSI under an oxidative and redox atmosphere. We find that Pt-assisted TiO2 amorphization is the key to the transition of various SMSI states at different conditions, which elevates Ti chemical potential via amorphization toward low-coordinated [TiO4]. Finally, explainable machine learning models were developed to predict nonclassical SMSI cases and clarify their rarity in nature.