Reverse Oriented Dual-Interface Built-in Electric Fields of Robust Pd1Mo1Ta2Oα Bifunctional Electrocatalysis for Zinc-Air Batteries

Abstract

It is imperative yet challenging for developing highly efficient multifunctional electrocatalysts for future sustainable energy pursuits. Herein, dual-interface reinforced reverse orientation of built-in electric fields (BIEFs) is reported in Pd₁Mo₁Ta₂Oα in-plane heterostructure, where amorphous Ta₂O₅ and PdO_δ particles are confined to PdMo nanosheet, for robust bifunctional electrocatalysts of rechargeable zinc–air batteries. The as-synthesized electrocatalyst (Pd₁Mo₁Ta₂Oα) exhibits remarkable catalytic activity toward oxygen reduction (E_on = 0.95 V, E_1/2 = 0.81 V) and oxygen evolution (η₁₀ = 401 mV) reactions with high kinetics and operational stability. These enhanced bifunctional electrocatalytic activities of Pd₁Mo₁Ta₂Oα are attributed to the synergistic collaboration of dual-interface BIEFs, where PdMo || PdO_δ initiating BIEF₁ orientation is parallel to OER external electric field (ExEF) and Ta₂O₅ || PdO_δ/PdMo initiating BIEF₂ orientation is parallel to ORR ExEF. In particular, the rechargeable zinc-air battery (ZAB) with the as-designed Pd₁Mo₁Ta₂Oα electrocatalysts delivers a high specific capacity of 1050 mAh g⁻¹ and stable voltage profiles over 800 cycles. Therefore, this work provides the structural and interfacial designs of bifunctional electrocatalysts with the reverse oriented BIEFs that synergistically enhance intrinsic catalytic activity and electronic transport for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER).