Surface reconstruction enabled o-PdTe@Pd core-shell electrocatalyst for efficient oxygen reduction reaction

Abstract

Palladium-based alloy catalysts have been employed as one of the potential candidates for oxygen reduction reaction (ORR), but the dissolution of transition metal hinders their application. Herein, structure ordered PdTe intermetallic with Pd shell (o-PdTe@Pd) are synthesized via an electrochemical etching driven surface reconstruction strategy. The surface reconstruction could tune the electronic structure, weaken the adsorption energy of reaction intermediates on o-PdTe@Pd, resulting in enhanced electrocatalytic activity for ORR. The mass activity of o-PdTe@Pd is about 3.3 and 2.7 times higher than that of Pd/C in acid and alkaline, respectively. Besides, the half-potentials for ORR decay only about 44 mV and 12 mV after 30 k cycles accelerated durability test in acid and alkaline media, respectively. The enhanced durability originates from the resistance of Te atoms dissolve in the ordered PdTe intermetallic core and the core-shell structure. When assembled in a Zn-air battery, o-PdTe@Pd electrode delivers a higher specific capacity (794 mAh/g) and better cycling stability than Pt/C.