Unravelling the Electrocatalytic Activity of LaFeO3 Perovskite towards O2 Reduction Reaction

Abstract

The oxygen reduction reaction (ORR) plays a vital role in renewable energy technologies, such as fuel cells. The performance of solid-polymer-electrolyte fuel cells depends on sluggish ORR kinetics, which poses a key challenge. To address this issue, extensive research has been conducted to explore non-Pt-based materials as potential alternatives for enhancing the ORR performance. In the present study, we theoretically investigated the structural and electronic properties of bulk LaFeO₃ perovskite using the GGA+U approach within the Vienna Ab Initio Simulation Package (VASP) framework. A (001) plane was cleaved from the bulk LaFeO₃ material to model a 2D monolayer of LaFeO₃, which was found to exhibit a band gap of 0 eV, indicating its potential to be used as an electrocatalyst for fuel cell applications. The complete ORR pathway was explored on the surface of the 2D monolayer LaFeO₃ perovskite. Both the associative and dissociative reaction mechanisms were studied by computing the change in Gibbs free energy (ΔG) for all of the reaction steps involved in ORR. Our findings demonstrate that the 2D LaFeO₃ monolayer exhibits exceptional electrocatalytic activity and favors the four-electron associative mechanism over the dissociative one. This study proposes that the 2D monolayer of LaFeO₃ can serve as an alternate ORR electrocatalyst to expensive platinum in fuel cells. Overall, these results offer insights into the potential application of the subject perovskite as a fuel cell material and provide profound insight into the O₂ reduction process on 2D perovskite-derived catalysts, including interactions with residual H₂O during the reaction, while also shedding light on the properties and behavior of active sites.