Two-dimensional metallic tantalum ditelluride with an intrinsic basal-plane activity for oxygen reduction: A microkinetic modeling study

Two-dimensional (2D) materials have exhibited great potential for replacing costly Pt for oxygen reduction reaction (ORR) because of their distinctive structural features and high pre-site activity. However, their performance is generally hindered by the limited density of active sites (e.g., at the layer edges). Although they feature a high exposure of surface sites, these sites are typically inert for ORR. Herein, through density functional theory calculations, we propose a promising ORR catalyst candidate, a 2D TaTe2 nanosheet, which has an intrinsic high basal-plane activity. Both of the thermodynamic and kinetic processes are explored, which demonstrates that the basal-plane Te sites of the TaTe2 nanosheet have great potential for facilitating ORR. Specifically, we construct a microkinetic model of ORR proceeding on TaTe2, which unveils its dynamic intermediate coverage under different electrode potentials and identifies the dominating associative pathway. The theoretical half-wave potential of TaTe2 is predicted to be 0.87 V, which exceeds those of the well-established Pt (111) and Fe–N–C single-atom catalysts computed at the same level. This study not only presents the first 2D, non-Pt ORR catalyst candidate with an intrinsic basal-plane activity but also offers a rational methodology for unveiling the mechanism/activity of ORR and other electrochemical reactions.