Pt-Embedded CuO x-CeO2 Multicore-Shell Composites: Interfacial Redox Reaction-Directed Synthesis and Composition-Dependent Performance for CO Oxidation.

Exploring the state-of-the-art heterogeneous catalysts has been a general concern for sustainable and clean energy. Here, Pt-embedded CuO x-CeO2 multicore-shell (Pt/CuO x-CeO2 MS) composites are fabricated at room temperature via a one-pot and template-free procedure for catalyzing CO oxidation, a classical probe reaction, showing a volcano-shaped relationship between the composition and catalytic activity. We experimentally unravel that the Pt/CuO x-CeO2 MS composites are derived from an interfacial autoredox process, where Pt nanoparticles (NPs) are in situ encapsulated by self-assembled ceria nanospheres with CuO x clusters adhered through deposition/precipitation-calcination process. Only Cu-O and Pt-Pt coordination structures are determined for CuO x clusters and Pt NPs in Pt/CuO x-CeO2 MS, respectively. Importantly, the close vicinity between Pt and CeO2 benefits to more oxygen vacancies in CeO2 counterparts and results in thin oxide layers on Pt NPs. Meanwhile, the introduction of CuO x clusters is crucial for triggering synergistic catalysis, which leads to high resistance to aggregation of Pt NPs and improvement of catalytic performance. In CO oxidation reaction, both Ptδ+-CO and Cu+-CO can act as active sites during CO adsorption and activation. Nonetheless, redundant content of Pt or Cu will induce a strongly bound Pt-O-Ce or Cu-[O x]-Ce structures in air-calcinated Pt/CuO x-CeO2 MS composites, respectively, which are both deleterious to catalytic reactivity. As a result, the composition-dependent catalytic activity and superior durability of Pt/CuO x-CeO2 MS composites toward CO oxidation reaction are achieved. This work should be instructive for fabricating desirable multicomponent catalysts composed of noble metal and bimetallic oxide composites for diverse heterogeneous catalysis.