The Synergy of the Electric Polarization and Built-In Electric Field for Efficient OER/ORR Supported on 2D Ferroelectric TM-Gr@Ga2O3 Heterojunctions Using Constant-Potential Methods

The pursuit of efficient oxygen reduction and evolution reactions (ORR/OER) using non-noble-metal catalysts is a coveted goal, yet it presents considerable challenges. In this study, we utilize first-principles calculations to engineer heterojunctions by integrating Ga2O3 monolayers with transition metal-doped graphene (TM-Gr) and then systematically evaluate the catalytic performance of these TM-Gr@Ga2O3 heterojunctions in the OER and ORR. Our results reveal that the synergistic effect of the built-in electric field created by the charge transfer and the Ga2O3 electric polarization markedly enhances the catalytic activity for OER/ORR. Altering Ga2O3 polarization orientations synergistically affects interfacial charge transfer and monolayer charge distribution. This involves charge redistribution across monolayers aligned with intrinsic interfacial charge transfer, including both interfacial and intralayer transfer, driven by the system’s inherent polarization. Using a constant charge approach, 69 systems were evaluated as the potential electrocatalysts, including TM-Gr, TM-Gr@Ga2O3↑, and TM-Gr@Ga2O3↓, for which TM-Gr@Ga2O3 produces more high-performance catalyst candidates compared with TM-Gr. Furthermore, detailed analysis of highly active catalysts based on the constant-charge method such as Co-Gr@Ga2O3↓, Co-Gr@Ga2O3↑, and Ni-Gr@Ga2O3↑ through constant-potential assessment and microkinetic modeling revealed the best performance with overpotentials of 0.23 (OER) and 0.21 V (ORR) and half-wave potentials of 0.85 V and potentials of 1.36 V at a current density of 10 mA cm–2 in acidic or alkaline conditions. This research provides a theoretical foundation for developing efficient nonprecious metal electrocatalysts.