3d–5d Orbital Hybridization in Nanoflower‐Like High‐Entropy Alloy for Highly Efficient Overall Water Splitting at High Current Density

Abstract

Exploring highlyefficient electrocatalysts for overall water splitting is a challenging butnecessary task for development of green and renewable energy. Herein, PtIrFeCoNi high-entropy alloy nanoflowers (HEA NFs) withstrong 3d-5d orbital hybridization were fabricated to achieve highly efficientoverall water splitting at high current density. The Pt₂₆Ir₇Fe₁₃Co₂₂Ni₃₂ HEA NFs achieved a 57.52-fold higher than commercial IrO₂ in turnoverfrequency (TOF) for oxygen evolution reaction (OER). Besides, its TOF value forhydrogen evolution reaction (HER) was 2.11-fold higher than that of commercialPt/C. The cell voltages based on Pt₂₆Ir₇Fe₁₃Co₂₂Ni₃₂ HEA NFs for overall water splitting were only 1.594 V and 1.861 V at currentdensities of 100 mA cm^-2 and 500 mA cm^-2, which weresignificantly lower than those of Pt/C.