Atomic scale deposition of Pt around Au nanoparticles to achieve much enhanced electrocatalysis of Pt

We report an electrochemical method to deposit atomic scale Pt on a 5 nm Au nanoparticle (NP) surface in N₂-saturated 0.5 M H₂SO₄. Pt is provided by the Pt wire counter electrode via one-step Pt wire oxidation, dissolution, and deposition realized by controlled electrochemical scanning. Scanning from 0.6–1.0 V (vs. RHE) for 10 000 cycles gives Au_98.2Pt_1.8, which serves as an excellent catalyst for the formic acid oxidation reaction, showing 41 times higher specific activity (20.19 mA cm⁻²) and 25 times higher mass activity (10.80 A mg_Pt⁻¹) with much better CO-tolerance and stability than commercial Pt. Our work demonstrates a unique strategy to minimize the use of Pt as a catalyst for electrochemical reactions.