Surface‐engineered perovskite oxides enabling dual activation of lattice and adsorbed oxygen for <scp>CO</scp> oxidation

Abstract Catalytic oxidation using perovskite oxides is a promising technology for mitigating environmental and health risks associated with CO emissions. A fundamental constraint for perovskite oxides, however, lies in the limited low‐temperature reactivity of oxygen species. While the dual activation of lattice oxygen (O latt ) and adsorbed oxygen (O ads ) is recognized as an effective strategy, achieving it in perovskite oxides remains a significant and underexplored challenge. This study addresses this challenge through a novel surface engineering strategy employing dilute TiCl 4 solution treatment. The treatment process on La 0.6 Sr 0.4 CoO 3 (LSCO) simultaneously achieves two distinct functions: (i) the removal of surface A‐site segregation to expose Co‐site termination, thereby facilitating O ads activation; (ii) the incorporation of Ti dopant, which enhances the CoO covalency to boost O latt reactivity. This concerted dual activation mechanism enables the LSCO‐Ti catalyst to operate via both Mars–van Krevelen (O latt ‐mediated) and Langmuir–Hinshelwood (O ads ‐mediated) pathways, leading to its exceptional activity of 90% CO conversion at a remarkably low temperature of 92°C. Furthermore, the Ti dopant also optimizes O 2 adsorption and suppresses carbonate accumulation, ensuring stable performance for over 50 h at 150°C. Our work provides a novel mechanistic framework for designing high‐performance perovskite catalysts via synergistic surface modification.