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

Xu, Bingyan; Liu, Tianyang; Liang, Xiaocong; Dou, Wenjie; Geng, Hongbo; Yu, Zhiyang; Li, Yafei; Zhang, Ying et al. · Adv Mater · 2022

basic_science · Level V

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Abstract

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 Pd<sub>20</sub> Sb<sub>7</sub> phase is successfully synthesized. Benefiting from the high proportion of the unique exposed Pd<sub>20</sub> Sb<sub>7</sub> (003) surface, Pd<sub>20</sub> Sb<sub>7</sub> rhombohedra display much enhanced ethanol oxidation reaction (EOR) and oxygen reduction reaction performance compared with commercial Pd/C. Moreover, Pd<sub>20</sub> Sb<sub>7</sub> 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 Pd<sub>20</sub> Sb<sub>7</sub> rhombohedra can not only reduce the excessive adsorption of CH<sub>3</sub> CO* to CH<sub>3</sub> COOH 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.