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

Abstract

Exploring the state-of-the-art heterogeneous catalysts has been a general concern for sustainable and clean energy. Here, Pt-embedded CuO -CeO multicore-shell (Pt/CuO -CeO 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 -CeO MS composites are derived from an interfacial autoredox process, where Pt nanoparticles (NPs) are in situ encapsulated by self-assembled ceria nanospheres with CuO clusters adhered through deposition/precipitation-calcination process. Only Cu-O and Pt-Pt coordination structures are determined for CuO clusters and Pt NPs in Pt/CuO -CeO MS, respectively. Importantly, the close vicinity between Pt and CeO benefits to more oxygen vacancies in CeO counterparts and results in thin oxide layers on Pt NPs. Meanwhile, the introduction of CuO 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 Pt-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 ]-Ce structures in air-calcinated Pt/CuO-CeO MS composites, respectively, which are both deleterious to catalytic reactivity. As a result, the composition-dependent catalytic activity and superior durability of Pt/CuO -CeO 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.

Elucidating the Nature of the Cu(I) Active Site in CuO/TiO2 for Excellent Low-Temperature CO Oxidation

“…The employment of metal oxide support such as CeO 2 , − TiO 2 , , and MnO x to form composite materials has been proved effective for the stabilization Cu + species. Among the above-mentioned metal oxide supports, TiO 2 attracts special attention owing to its outstanding physical/chemical stability, low cost, and ability to stabilize Cu + species. − Stable Cu + was found to exist in the model CuTiO x mixed oxide film prepared via a vacuum-assisted sputter deposition method.…”

Facile synthesis of Au embedded CuOx-CeO2 core/shell nanospheres as highly reactive and sinter-resistant catalysts for catalytic hydrogenation of p-nitrophenol

“…More recently, numerous successful attempts have been realized on the basis of the interfacial auto-catalytic redox reactions for preparing ceria-encapsulated noble metal or transition metal oxide nanocatalysts with core/shell nanostructures [25]. For instance, our group has developed a novel method for preparing Pt-embedded CuOx-CeO2 multicore-shell nanostructures at room temperature [26]. However, an effective strategy for the integration of Au NPs and CuOx-CeO2 support with core/shell structure has not been realized yet.…”

Co3O4–CuCoO2 Nanomesh: An Interface-Enhanced Substrate that Simultaneously Promotes CO Adsorption and O2 Activation in H2 Purification

“…Nanomaterials have been extensively studied in the past decades for the heterogeneous catalysis fields, especially in redox heterogeneous catalysis. − It is well established that these redox reactions generally follow the Mars–Van Krevelen mechanism in terms of four primary steps: (i) reactant adsorption, (ii) formation of active oxygen, (iii) reactant reacting with active oxygen, and (iv) product desorption. , Among all these steps, reactant adsorption and oxygen activation are two crucial steps that govern the selectivity of product and reactants conversion. , Although copious efforts have been tried to design an advanced catalyst, the problem is still not well solved in simultaneous adsorption of reactive gases and activation of oxygen species, which is seriously restricting the application of nanomaterials in many important catalytic fields. , Thus, it is urgent, but also highly challenging, to rationally design catalysts that could give effective adsorption of reactant and activation of oxygen species.…”