Sub-Nanometer Pt Clusters on Defective NiFe LDH Nanosheets as Trifunctional Electrocatalysts for Water Splitting and Rechargeable Hybrid Sodium–Air Batteries

It is challenging to develop highly efficient and stable multifunctional electrocatalysts for improving the hydrogen evolution reaction (HER), oxygen (OER), reduction (ORR) sustainable energy conversion storage systems such as water-alkali electrolyzers (WAEs) hybrid sodium-air batteries (HSABs). In this work, sub-nm Pt nanoclusters (NCs) on defective NiFe layered double hydroxide nanosheets (NixFe LDHs) are synthesized by a facile electrodeposition method. Due synergistic effect between NCs abundant atomic M(II) defects, along with hierarchical porous nanostructures, Pt/NixFe LDHs catalysts exhibit superior trifunctional electrocatalytic activity durability toward HER/OER/ORR. A WAE fabricated electrodes needs 1.47 V reach current density of 10 mA cm-2, much lower than that mixed 20% Pt/C Ir/C catalysts. An HSAB assembled binder-free air cathode displays high open-circuit voltage, narrow overpotential gap, remarkable rechargeability. This work provides feasible strategy constructing freestanding systems.