Encapsulation of Platinum by Titania under an Oxidative Atmosphere: Contrary to Classical Strong Metal–Support Interactions

Classical strong metal–support interaction (SMSI) has attracted intensive attention in the heterogeneous catalysis field; however, its crystalline TiOx overlayer and reversible feature often curtail the effect of classical SMSI on enhancing the catalytic performance of supported metal catalysts in oxidation reactions, especially at elevated temperatures. Here, we report the evidence that Pt nanoparticles can be encapsulated by an amorphous and permeable TiOx cover layer in Pt/TiO2 catalysts under an oxidative atmosphere, where the keys are the utilization of melamine, followed by annealing in nitrogen flow and further calcination at 800 °C in air. More importantly, the formed overlayer is stabilized against re-oxidation at 400–600 °C in air, in sharp contrast to the retreat of the TiOx overlayer by subsequent oxidation treatment in classical SMSI. Such an extraordinary strategy is further demonstrated on titania-supported Pd and Rh nanoparticles, paving a promising way for designing supported platinum group metal-based catalysts with high activity and stability.