Dealloyed PtAuCu electrocatalyst to improve the activity and stability towards both oxygen reduction and methanol oxidation reactions

Highlights: • PtAuCu nanocatalyst is synthesized via a simple galvanic displacement method. • After dealloying, a rich PtAu skin is exposed on the surface of the PtAuCu. • Dealloyed PtAuCu is demonstrated with enhanced ORR activity and superior stability. • Dealloyed PtAuCu displays excellent MOR activity and CO tolerance ability. • The high catalytic activity is due to geometric, electronic structural effect. - Abstract: In the present work, we synthesize ternary PtAuCu nanoparticles supported on carbon by a sequent galvanic displacement method and study the relationship between the structure and properties. X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) reveal that PtAuCu displays a compressive lattice, and X-ray photoelectron spectroscopy (XPS) also presents an altered electronic environment. After electrochemical dealloying, a rich PtAu skin is exposed on the surface of the PtAuCu. With the changes in the geometric, electronic and surface structure, the PtAuCu electrocatalyst shows an enhancement in ORR and MOR activity, as well as an improvement in their stability. The Pt₁₀Au₁₀Cu₆₄/C catalyst exhibits a Pt mass activity of 0.376 A mg_Pt⁻¹ at 0.85 V for the ORR, which is 2.22 times higher than that of Pt/C, and the current density at 0.8 V for the MOR is 4.43 times higher than that of Pt/C. Furthermore, Pt₁₀Au₃Cu₄₄/C exhibits superior stability for the ORR, with a mass activity loss of only 7.25% after 3000 cycles, whereas Pt/C exhibits a 48.82% loss under the same conditions.