A seed-confined strategy to alloy immiscible systems for methanol oxidation

The design of high-performance alloy catalysts is constrained by thermodynamic immiscibility among constituent elements (for example, W–Bi). High-entropy designs can overcome immiscibility by incorporating multiple elements, but active sites are often diluted and structure–property relationships are obscured. Here we report a compositionally minimalist seed-confined alloying strategy that uses a single thermodynamically selected seed, rather than multiple additional alloying elements, together with pathway-controlled alloy formation. Pt was selected as a representative seed because favourable Pt–W and Pt–Bi interactions improve ternary alloying accessibility while providing active sites for methanol oxidation; pre-anchoring creates dispersed incorporation centres, promotes multi-element association and suppresses competing phases. The resulting WBi–Pt@B/C catalyst comprises dispersed, robust nanoparticles with a diameter of ~3.6 nm and delivers a mass activity of 13.41 A per mg Pt in methanol oxidation, retaining 94.1% of its activity after 5,000 cycles. This strategy provides a practical route to the construction of compositionally simple nanoscale alloy catalysts with chemically complementary functions.