Constructing Janus Structures and Rich Electron Pool in 2D TMTe Nanostructures To Achieve OER/ORR Electrocatalysts

Through first-principles structure search calculations, we have identified ten hitherto unknown two-dimensional (2D) Janus-wrinkled TMTe monolayers (TM = Ni, Pd, Pt, Co, Rh, Ir, Fe, Ru, Os, and Hf) by screening 3d, 4d, and 5d transition metal atoms. These monolayers exhibit high stability and metallic conductivity. Among the discovered materials, the 2D PdTe (η_OER/ORR = 0.46/0.22 V) and PtTe (η_OER/ORR = 0.46/0.32 V) monolayers can demonstrate superior bifunctional catalytic performance for oxygen evolution and oxygen reduction reactions (OER/ORR), with lower overpotential than the state-of-the-art IrO₂ for OER and Pt (111) for ORR, respectively. The TM- and Te-sides originating from the unique Janus configurations play a crucial role in the high OER and ORR catalytic activities, respectively. Furthermore, by stacking the monolayer structures, eight new (TMTe)₂ bilayers with high stability and metallic conductivity can be achieved, which possess an internal metal layer, forming a rich electron pool. This effectively improves oxygen adsorption and activity on some bilayers, including (PdTe)₂, (PtTe)₂, (RhTe)₂, and (IrTe)₂, by transferring more electrons to the adsorbed O₂ molecule, leading to considerably high ORR catalytic performance (η_ORR = 0.16-0.44 V). Moreover, detailed analyses of the catalytic mechanisms have been conducted. These intriguing findings can offer new insights for designing low-cost and high-performance electrocatalysts for OER and ORR reactions, with the potential to replace related noble metal catalysts used in water splitting, fuel cells, metal-air batteries, etc.