Charge redistribution engineering in Mn_5.64P₃/CePO₄ heterostructure enhances oxygen reduction for advanced zinc-air...

Tailoring the electronic structure via charge redistribution is a promising strategy for constructing oxygen reduction reaction (ORR) catalysts to accelerate reaction kinetics for metal-air batteries. Herein, an approximately 3.9 nm thin-layer of Mn_5.64P₃/CePO₄ heterostructure stabilized on mesoporous carbon spheres (Mn_5.64P₃/CePO₄@Cs) was synthesized via mild hydrothermal and high-temperature phosphating approaches. The resultant Mn_5.64P₃/CePO₄@Cs demonstrates superior ORR performance in 0.1 M KOH with a kinetic current density of 5.2 mA cm^-2 at 0.8 V, increasing 2.4- and 5.8-fold compared to CePO₄@Cs and Mn_5.64P₃@Cs, respectively. Moreover, the zinc-air battery (ZAB) incorporating Mn_5.64P₃/CePO₄@Cs showcases a peak power density of 168 mW cm^-2 and robust durability of 400 h, surpassing the advanced Pt/C. Experiments and density functional theory (DFT) calculations indicate that the built-in electric field (BEF)-induced charge asymmetry regulates the d-band center of Mn_5.64P₃/CePO₄@Cs and reduces the energy barrier of oxygen intermediates, thereby improving ORR catalytic performance. This work provides a promising avenue to rationally manipulate the electronic structure of ORR catalysts by constructing heterostructure driven BEF strategy.