Spatially Immobilized PtPdFeCoNi as an Excellent Bifunctional Oxygen Electrocatalyst for Zinc–Air Battery

Abstract Developing efficient oxygen electrocatalysts with low cost, high catalytic activity, and robust stability remains a formidable challenge for rechargeable zinc–air batteries (ZABs). Herein, highly dispersed ultrasmall PtPdFeCoNi high‐entropy alloy nanoparticles with a size of ≈ 2 nm and randomly distributed multimetallic single atoms spatially immobilized on the 3D hierarchically ordered porous nitrogen‐doped carbon skeleton (denoted as PtPdFeCoNi/HOPNC) are successfully synthesized via ultra‐rapid Joule heating process. The spatial immobilization on 3D HOPNC skeleton is the key to the high dispersion of multi‐active sites of oxygen electrocatalysts, and the formed hierarchical pore structure is conducive to the successful construction of the rapid mass transfer channel. As a result, the as‐prepared PtPdFeCoNi/HOPNC exhibits a positive half‐wave potential of 0.866 V versus RHE for oxygen reduction reaction (ORR), a low overpotential of 310 mV at 10 mA cm⁻² for oxygen evolution reaction (OER), and low Tafel slopes for both ORR and OER. Furthermore, ZAB using PtPdFeCoNi/HOPNC as bifunctional oxygen catalysts exhibits excellent rate performances and superior cycling stability, surpassing that of a commercial Pt/C‐RuO₂ mixture. The spatial immobilization strategy of HOPNC provides a new idea for the design and synthesis of efficient catalysts for various applications.