Rational design of B-Site single-atom doped LaMnO3 for CO chemical looping combustion: a DFT study

Abstract

Perovskite oxides such as LaMnO3 are widely investigated as oxygen carriers (OCs) in chemical looping combustion (CLC) due to their tunable catalytic and structural properties. In this study, density functional theory (DFT) calculations were employed to explore the effects of B-site single-atom doping on the CO oxidation performance of LaMnO3. Among 25 possible doped configurations, eight were identified as thermodynamically stable, providing a basis for further activity analysis.The adsorption and activation of CO on these stable doped surfaces were examined at the electronic level, followed by evaluation of the reaction energy barriers. Six doped structures (V-, Cr-, Ni-, Rh-, and Cd-LaMnO3) displayed lower barriers than pristine LaMnO3, with Ni-LaMnO3 showing the lowest value of 0.770 eV, corresponding to a 61% reduction. Ab initio molecular dynamics (AIMD) simulations further confirmed the kinetic stability of these low-barrier structures under CLC conditions. Finally, structureactivity-stability relationships were explored, revealing that the +3 ionic radius and the Bader charge transfer of the doped atom serve as robust descriptors for predicting both stability and catalytic activity. Collectively, these findings provide atomic-level insights for the rational design of doped perovskite oxides with enhanced performance in CO CLC, demonstrating the potential of targeted B-site doping strategies to improve catalytic activity.