TiO2-facet-dependent reconstruction of Pt nanoparticles during CO oxidation

Facet engineering of reducible oxide supports is a powerful strategy for tuning metal–support interactions. We show that this facet dependence extends beyond intrinsic support properties to govern the initial morphology and reaction-induced restructuring behaviour of supported Pt nanoparticles during CO oxidation. For ~1.8 nm Pt nanoparticles on anatase TiO2, microscopy and spectroscopy show that the (001) facet stabilises a wetted Pt structure with expanded interfacial contact, whereas the (101) facet favours compact cuboctahedral nanoparticles with limited interface. Genetic algorithm and graph neural network-based simulations reproduce these facet-dependent structures and support distinct restructuring under CO oxidation. DFT calculations support facile oxygen activation on the (001) facet throughout the MvK pathway, while reaction-order analysis and catalytic cycle tests indicate that the reaction-evolved Pt–TiO2(001) interface synergistically couples with oxygen vacancies to enable efficient oxygen replenishment, further lowering the activation barrier by ~25% after the initial run. This work identifies support facets as regulators of dynamic metal–support interfaces governing catalytic performance. Engineering the exposed facets of reducible oxide supports is an effective way to tune metal–support interactions. Here, the authors show that the support facet directs the structural evolution of Pt nanoparticles and the dynamic metal–support interface, thereby governing catalytic performance during CO oxidation.