In Situ Growth of Ultrafine Pt Nanoparticles onto Hierarchical Co₃O₄ Nanosheet‐Assembled Microflowers for Efficient Electrocatalytic Hydrogen Evolution

Abstract

Abstract The development of Pt‐based electrocatalysts with high Pt utilization efficiency toward the hydrogen evolution reaction (HER) is of great significance for the future sustainable hydrogen economy. For rational design of high‐performance HER electrocatalyst, the simultaneous consideration of both thermodynamic and kinetic aspects remains greatly challenging. Herein, a simple template‐derived strategy is demonstrated for the in situ growth of ultrafine Pt nanoparticles onto Co 3 O 4 nanosheet‐assembled microflowers (abbreviated as Pt/Co 3 O 4 microflowers hereafter) by using the pre‐fabricated PtCo‐based Hofmann coordination polymer as reactive templates. The elaborate preparation of such intriguing hierarchical architecture with well‐dispersed tiny Pt nanoparticles, abundant metal/oxide heterointerfaces and open configuration endows the formed Pt/Co 3 O 4 microflowers with high Pt utilization efficiency, rich active sites, lowered energy barrier for water dissociation and expedited reaction kinetics. Consequently, the Pt/Co 3 O 4 microflowers exhibit superior HER activity with a relatively low overpotential of 34 mV to deliver a current density of 10 mA cm −2 , small Tafel slope (34 mV dec −1 ) and outstanding electrochemical stability, representing an attractive electrocatalyst for practical water splitting. What's more, our concept of in situ construction of metal/oxide heterointerfaces may provide a new opportunity to design high‐performance electrocatalysts for a variety of applications.