Entropy Engineering Activates Cu-Fe Inertia Center From Prussian Blue Analogs With Micro-Strains for Oxygen Electrocatalysis in Zn-Air Batteries

Abstract

By the random distribution of metals in a single phase, entropy engineering is applied to construct dense neighboring active centers with diverse electronic and geometric structures, realizing the continuous optimization of multiple primary reactions for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Many catalysts developed through entropy engineering have been built in nearly equimolar ratios to pursue high entropy, hindering the identification of the active sites and potentially diluting the concentration of real active sites while weakening their electronic interactions with reaction intermediates. Herein, this work proposes an entropy-engineering strategy in metal nanoparticle-embedded nitrogen carbon electrocatalysts, implemented by entropy-engineered Prussian blue analogs (PBA) as precursors to enhance the catalytic activity of primary Cu-Fe active sites. Through the introduction of the micro-strains driven by entropy engineering, density functional theory (DFT) calculations and geometric phase analysis (GPA) using Lorentz electron microscopy further elucidate the optimization of the adsorption/desorption of intermediates. Furthermore, the multi-dimensional morphology and the size diminishment of the nanocrystals serve to expand the electrochemical area, maximizing the catalytic activity for both ORR and OER. Notably, the Zn-air battery assembled with CuFeCoNiZn-NC operated for over 1300 h with negligible decay. This work presents a paradigm for the design of low-cost electrocatalysts with entropy engineering for multi-step reactions.