Lattice Oxygen Engineering on Perovskite Oxide Catalysts: Concurrent Enhancement of Reactivity and Replenishment for Volatile Organic Compounds Oxidation
Bin Wang, Yue Xuan, Gengde Zhu, Yanjie Liang, Yue Peng, Qiaowan Chang, Tao Luan, Dong Wang, Junhua Li
Abstract
The catalytic volatile organic compound oxidation poses a dilemma for perovskite (ABO 3 ) 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 O 2 dissociation in electron-deficient environments. Herein, we compress [Co/MnO 6 ] octahedra through A-site Cs + doping in the double perovskite (La 2 CoMnO 6−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, La 1.70 Cs 0.30 CoMnO 6−δ exhibits a remarkable 30.2-fold and 4.5-fold increase in toluene oxidation rates at 200 °C compared to LaMnO 3 and La 2 CoMnO 6−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 CO 2 and H 2 O 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.