Lattice Oxygen Engineering on Perovskite Oxide Catalysts: Concurrent Enhancement of Reactivity and Replenishment for Volatile Organic Compounds Oxidation

The catalytic volatile organic compound oxidation poses a dilemma for perovskite (ABO3) catalysts, as their high lattice oxygen reactivity (electron-deficient O-(2-x)) depends on attracting coordinated oxygen electrons through an increased electronegativity of B-site cations, but this impedes the healing of oxygen vacancies and thus results in a low concentration of active lattice oxygen due to the limited O2 dissociation in electron-deficient environments. Herein, we compress [Co/MnO6] octahedra through A-site Cs+ doping in the double perovskite (La2CoMnO6-σ), which optimizes the orbital hybridization between Co/Mn 3d and O 2p. This promotes electron transfer from O to Co/Mn while reducing Co/Mn electronegativity, resulting in a synergistic improvement of lattice oxygen reactivity and oxygen vacancy healing. As a result, La1.70Cs0.30CoMnO6-δ exhibits a remarkable 30.2-fold and 4.5-fold increase in toluene oxidation rates at 200 °C compared to LaMnO3 and La2CoMnO6-σ, respectively, surpassing the reported Co/Mn-based perovskites. Due to its ultrahigh lattice oxygen reactivity and abundant active lattice oxygen, benzaldehyde intermediates predominantly governed by adsorbed oxygen are synchronously oxidized to CO2 and H2O by lattice oxygen, enabling Mars-van Krevelen reactions to function efficiently coupled with Langmuir-Hinshelwood reactions. This work harmonizes the reactivity and abundance of lattice oxygen, offering a robust strategy to advance the development of high-performance perovskite catalysts for catalytic oxidation.