Surface-Strained Intermetallic Pd3Pb Concave Nanocubes for Selective C2-Pathway Ethanol Electrooxidation

Selective electrooxidation of ethanol to acetate via the C2 pathway offers a sustainable route to high-value chemicals, but achieving high activity and selectivity on Pd-based catalysts remains challenging. Here, we report ordered intermetallic Pd3Pb concave nanocubes (CNCs) with engineered surface strain as selective electrocatalysts for ethanol-to-acetate conversion. The Pd3Pb CNCs deliver a mass activity of 1841.7 mA mg-1 and a specific activity of 5.6 mA cm-2 in an alkaline electrolyte, outperforming Pd3Pb nanocuboids and commercial Pd/C. Notably, 1H NMR quantification reveals a faradaic efficiency of ∼92% toward acetate, demonstrating outstanding C2 pathway selectivity. The concave morphology introduces high-index facets and localized lattice strain, while the ordered intermetallic structure modulates the Pd d-band center. DFT calculations show that tensile strain on Pd3Pb(111) and (100) surfaces lowers the rate-determining barriers of the C2 pathway relative to the C1 pathway, kinetically favoring acetate formation. This work demonstrates that surface strain engineering in intermetallic Pd3Pb can effectively steer ethanol electrooxidation toward selective acetate production.