Pd-Sb Rhombohedra with an Unconventional Rhombohedral Phase as a Trifunctional Electrocatalyst

Crystal phase engineering is an important strategy for designing noble-metal-based catalysts with optimized activity and stability. From the thermodynamic point of view, it remains a great challenge to synthesize unconventional phases of noble metals. Here, a new class of Pd-based nanostructure with unconventional rhombohedral Pd20Sb7 phase is successfully synthesized. Benefiting from the high proportion of the unique exposed Pd20Sb7 (003) surface, Pd20Sb7 rhombohedra display much enhanced ethanol oxidation reaction (EOR) and oxygen reduction reaction performance compared with commercial Pd/C. Moreover, Pd20Sb7 rhombohedra are also demonstrated as an effective air cathode in non-aqueous Li-air batteries with an overpotential of only 0.24 V. Density functional theory calculations reveal that the unique exposed facets of Pd20Sb7 rhombohedra can not only reduce the excessive adsorption of CH3CO* to CH3COOH on Pd for promoting EOR process, but also weaken CO binding and CO poisoning. This work provides a new class of unconventional intermetallic nanomaterials with enhanced electrocatalytic activity.

Automated summary

This study successfully synthesized a new class of Pd-based nanostructures with unconventional crystal phases and demonstrated their enhanced electrocatalytic activity in ethanol oxidation reaction, oxygen reduction reaction, and non-aqueous Li-air batteries.