Abstract
Although researches on non-noble metal electrocatalysts have been made some progress recently, their performance in proton exchange membrane water electrolyzer (PEMWE) is still incomparable to that of noble-metal-based catalysts. Therefore, it is a more practical way to improve the utilization of precious metals in electrocatalysts for oxygen evolution reaction (OER) in the acidic medium. Herein, nanostructured IrCo@IrCoOx core-shell electrocatalysts composed of IrCo alloy core and IrCoOx shell were synthesized through a simple colloidally synthesis and calcination method. As expected, the hybrid IrCo-200 NPs with petal-like morphology show the best OER activities in acidic electrolytes. They deliver lower overpotential and better electrocatalytic kinetics than pristine IrCo alloy and commercial Ir/C, reaching a low overpotential (j = 10 mA/cm2) of 259 mV (vs. RHE) and a Tafel slope of 59 mV dec−1. The IrCo-200 NPs displayed robust durability with life time of about 55 h in acidic solution under a large current density of 50 mA/cm2. The enhanced electrocatalytic activity may be associated with the unique metal/amorphous metal oxide core-shell heterostructure, allowing the improved charge transferability. Moreover, the *OH-rich amorphous shell functions as the active site for OER and prevents the further dissolution of the metallic core and thus ensures high stability.
Core–Shell Prussian Blue Analogs with Compositional Heterogeneity and Open Cages for Oxygen Evolution Reaction
