Monolayer Ta2Se: A low-cost catalyst with enhanced stability and high basal plane activity for oxygen reduction reaction

The search for cost-effective two-dimensional (2D) electrocatalysts is accelerating as these materials emerge as pivotal alternatives to traditional energy technologies for fuel cells. In this work, we report a low-cost, highperformance Ta2Se monolayer as an electrocatalyst for the oxygen reduction reaction (ORR) through firstprinciples calculations. The Ta2Se monolayer exhibits notable stability and low cleavage energy, underscoring its practical potential for experimental synthesis. Our computations show that the Ta2Se monolayer has a metallic band structure with substantial electronic states at the Fermi level, which suggests the favorable electron transport properties. Remarkably, the outer Ta atoms in the basal plane of Ta2Se monolayer are identified as ORR active sites, exhibiting a competitive selection for dissociative and associative four-electron pathways alongside outstanding catalytic activity. Through examining the surface coverage impacts on ORR, we disclose that at a moderate oxygen coverage, the Ta2Se monolayer's limiting potential reaches approximately 0.9 eV, outstripping the conventional Pt electrodes, thus confirming its superior ORR catalytic capability. The low cost, active basal plane sites, and high ORR activity make the Ta2Se monolayer a competitive candidate for advanced fuel cell components.