Amorphous encapsulation engineering to overcome SMSI constraints in Pt@a-Nb₂O₅ catalysts for CO oxidation

In supported catalysts, strong metal–support interaction (SMSI) is pivotal for modulating catalytic performance. Challenges, such as active site shielding and insufficient interfacial reactivity, have emerged as key points of attention. Here, we propose an amorphous encapsulation strategy creating permeable overlayers that preserve metal accessibility while maximizing metal–support interfaces. The engineered Pt@a-Nb₂O₅ catalyst is synthesized through a two-step process involving the heat treatment of the Nb₂O₅ support followed by wet chemical reduction. This catalyst exhibits exceptional CO oxidation performance, achieving complete CO conversion at 165 °C and demonstrating remarkable stability for over 30 h at 205 °C. The amorphous Nb₂O₅ shell, rich in oxygen vacancies, modulates the electronic structure of Pt, creating dual adsorption sites for CO and O₂ and significantly improving catalytic activity. The catalyst design, which features an amorphous-coated heterostructure, along with the amorphous encapsulation preparation method, is expected to be applicable to a wider variety of supported catalyst systems and catalytic reactions.