Screening Efficient Pt-based Dual-Metal Atomic-Level Catalysts for Oxygen Reduction Reaction

Abstract

In this work, a computer aided screening strategy and density functional theory (DFT) are used together to screen and identify high-performance Pt-based dual-atom catalysts PtM-L₆@Gra (M = 3d, 4d, 5d, L = N, C, B) for oxygen reduction reactions (ORR). Comprehensive studies demonstrated that six representative electrocatalysts (i.e., PtCo-C₆@Gra, PtNi-C₆@Gra, PtZn-C₆@Gra, PtFe-N₆@Gra, PtCo-N₆@Gra, PtNi-N₆@Gra) show high ORR catalytic activities under both acidic and basic conditions with favorable overpotentials (among them, PtZn-C₆@Gra is the best candidate with the lowest η_ORR of 0.49 V). The ORR follows a 4-electron mechanism with the final product H₂O/OH^–. PtFe-, PtCo-, PtNi-N₆@Gra and PtCo-, PtNi-, PtZn-C₆@Gra demonstrate superior activities with low η_ORR due to their moderate adsorption strength of *OH. More importantly, intrinsic physical quantities are used to construct diverse and effective descriptors (such as (d_*(Pt-M) + χ_M) × ΔG_*→*O2, (d_*(Pt-M) + χ_M) × ΔG_*OH→*+OH-, (avg[d_a(Pt-M)] + χ_M) × ΔG_*→*O2 and (avg[d_a(Pt-M)] + χ_M) × ΔG_*OH→*+OH-) for rapid screening and identifying the promising electrocatalysts, unveiling the mechanism, and establishing the structure-activity relationship. The present study opens up an important route for the development of efficient low Pt catalysts for ORR, and will inspire the follow-up experimental and theoretical activities in this direction.