Asymmetric Pt1O4–Ov Dual Active Sites Induced by NbOx Clusters Promotes CO Synergistical Oxidation

Abstract

Pt/CeO₂ single-atom catalysts are attractive materials for CO oxidation but normally show poor activity below 150 °C mainly due to the unicity of the originally symmetric Pt₁O₄ structure. In this work, a highly active and stable Pt₁/CeO₂ single-site catalyst with only 0.1 wt % Pt loading, achieving a satisfied complete conversion of CO at 150 °C, can be obtained through fabricating asymmetric Pt₁O₄-oxygen vacancies (O_v) dual-active sites induced by well-dispersed NbO_x clusters. Specifically, the formation of new Ce–O–Nb interactions weakened the strength of the original Pt–O–Ce bond, thus transferring the originally near-perfect square-planar Pt₁O₄ into the distorted square-planar one, along with forming abundant O_v around the Pt site. Hence, the promoted CO activation on the asymmetric Pt₁O₄ structure and the facilitated dissociation of the O₂ on the neighboring O_v site synergistically improved the CO catalytic oxidation performance. The fabrication of such asymmetric Pt₁O₄–O_v double-active sites was also active for the oxidation of other typical hydrocarbons pollutants such as C₇H₈ and C₃H₆ from exhaust gases, shedding light on engineering high-efficiency Pt-based oxidation catalysts for low-temperature environmental catalysis.