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 = 0.46/0.22 V) and PtTe (η = 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 IrO 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) 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), (PtTe), (RhTe), and (IrTe), by transferring more electrons to the adsorbed O molecule, leading to considerably high ORR catalytic performance (η = 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.