Plasma-Induced Defect Engineering in Pt-Doped Perovskite Oxide Enhances Catalytic Oxidation via Strengthened Metal–Support Interactions

Perovskite oxides, despite their excellent thermal stability, are often limited in heterogeneous catalysis by insufficient exposure of active sites and low oxygen activity. Thermal plasma technology, capable of inducing surface and bulk structural reconstruction, represents an effective solution. Herein, Pt-doped LaMO₃ (M = Mn, Co, or Fe) perovskites are modified by high-temperature O₂ plasma treatment and evaluated in CO and toluene oxidation reactions. The designed plasma treatment significantly promotes the formation of surface defects, particularly oxygen vacancies (O_v). These defects not only stabilize metallic Pt (Pt⁰) species, but also facilitate the migration and surface exposure of Pt species from the bulk, thereby constructing abundant, highly active, and stable Pt⁰-O_v-Mn³⁺ synergistic active sites. They significantly enhance reactive oxygen species cycling, effectively promoting the adsorption and activation of CO and toluene, and thus enabling efficient low-temperature catalytic oxidation. Plasma-activated Pt-doped LaMnO₃ reduces the temperature for complete CO conversion by 40 °C and decreases the T₉₀ temperature for toluene conversion by nearly 80 °C. This work presents a universal plasma-activated strategy for designing high-performance noble-metal-based perovskite catalysts, holding significant promise for environmental catalysis.