Two-Dimensional Sandwich-Like Monolayers: Bimetallic Selenides/Tellurides as High-Activity Electrocatalysts for the Oxygen Reduction Reaction

The design of low-cost electrocatalysts for the oxygen reduction reaction (ORR) is of great importance for advancing hydrogen fuel cell technology. In this work, we employ density functional theory calculations to systematically evaluate the ORR electrocatalytic potential of unique two-dimensional sandwich-like VTMSe4 (TM = Co, Rh, Ir) and TMCoTe4 (TM = V, Nb, Ta) monolayers. Our findings indicate that these bimetallic monolayers can effectively activate adsorbed O2 molecules and exhibit outstanding ORR catalytic performance. The optimal overpotentials range from 0.32 to 0.33 V for the VTMSe4 series (TM = Co, Rh, Ir) and from 0.26 to 0.33 V for the TMCoTe4 series (TM = Nb, Ta), even outperforming the benchmark Pt catalyst. In addition to their outstanding catalytic activity, these monolayers also demonstrate high selectivity, excellent structural stability, and good conductivity. The fundamental catalytic mechanisms are thoroughly elucidated. This study not only proposes a range of promising candidate materials for the ORR but also provides new insights into the design of high-performance, low-cost alternatives to precious-metal-based catalysts for fuel cell applications.