Building Random Alloy Surfaces from IntermetallicSeeds: A General Route to Strain-Engineered Electrocatalysts with High Durability

Pt-based catalysts are common in fuel cells but suffer from high cost and poor durability. To overcome these limitations, earth-abundant metals are often incorporated with Pt in core@shell architectures or through alloy formation. Here, the concepts of a core@shell architecture, alloyed surfaces, and high-durability intermetallics are integrated into one nanostructure platform using seed-mediated co-reduction (SMCR). Specifically, random alloy PtM (where M = Ni, Co, Cu, or Fe) shells are deposited on intermetallic PdCu B2 seeds. Control of shell thickness and Pt:M ratios is also demonstrated, providing a general route to strain-engineered alloyed surfaces. The performance of these nanocatalysts was evaluated for the oxygen reduction reaction (ORR) as a function of shell thickness and shell composition, where PtCu and PtNi shells showed a 230% and 270% activity increase, respectively, compared to the Pt reference. This evaluation is coupled with Tafel plot analysis which shows significant changes in the Ta...