Maximize the Electrocatalytic Activity of Pt Toward Ethanol Oxidation via Engineering PdPt₁ Single-Atom Alloy Skin

Single-atom alloys (SAAs) emerge as an intriguing model system for electrocatalysis by combining the advantages of single-atom catalysts and nanoalloys, yet it faces the challenge in engineering their surface structure at the atomic level. Herein, to fully utilize active Pt sites to boost ethanol oxidation electrocatalysis, single-Pt-atoms anchored onto the surface of intermetallic Pd₅Bi₃ core-ultrathin Pd shell octahedrons, namely a tensile-strained PdPt₁ SAA skin, were rationally designed and engineered. This unique PdPt₁ SAA skin achieves a record-high mass activity (553.58 A mg_Pt ^-1 or 34.73 A mg_Pt+Pd ^-1) and outstanding durability toward ethanol oxidation in alkaline electrolyte, outperforming the current high-performance electrocatalysts. Density functional theory (DFT) calculations reveal that the isolated-Pt-atoms effectively enhance the adsorption of ethanol, accelerate the C2 pathway, and enhance the C-C bond cleavage of the *CH₂CO intermediate. The wet-chemical fabrication of SAA skin opens up a general strategy to construct model surface that completely exposes and stabilizes active atoms, facilitating the development of highly efficient electrocatalysts.