Synergistic Integration of Tensile-Strained Pt Shell and SnO_x Sites in a Core-Shell Nanocatalyst for Dual Enhancement...

Direct alcohol fuel cells (DAFCs) are promising energy conversion devices, but their widespread application is hindered by the sluggish kinetics and severe CO poisoning associated with the anode oxidation reactions. Here, we designed a novel core-shell electrocatalyst, PtPbSn/Pt@sub-SnO_x, which combines a Sn-modified PtPb intermetallic core, a tensile-strained Pt shell, and a sub-monolayer of SnO_x. This architecture was achieved via a facile one-pot synthesis. The introduced Sn is key to simultaneously inducing core lattice expansion, Pt-shell tensile strain, and surface oxophilic sites. For the methanol oxidation reaction, it exhibits a mass activity of ∼6.77 A mg^-1 _Pt, outperforming PtPb and commercial Pt/C. It also demonstrates exceptional long-term stability over 80 000 s and high CO tolerance, alongside promising activity for ethanol and ethylene glycol oxidation. Density functional theory calculations reveal that the synergy between the tensile-strained Pt shell and surface SnO_x species optimizes the electronic structure of Pt. This optimization leads to enhanced adsorption of CH₃OH and OH, weakened CO binding, and consequently, lowered energy barriers for the key steps. This work demonstrates that the synergistic design of a stable intermetallic core, a strained metal shell, and surface oxophilic species is an effective strategy for developing high-performance and durable electrocatalysts for DAFCs.