Strain effect of PtCu alloy aerogel nanocatalysts on the oxygen reduction reaction enhancement

Tuning their strain effect of Pt based alloy electrocatalysts is an efficient strategy to enhance the electrocatalytic performance toward oxygen reduction reaction (ORR) for proton exchange membrane fuel cells (PEMFCs). Herein, an efficient PtCu alloy aerogels (PtCu AAs) with adjustable Pt/Cu atomic ratio form a subtle lattice contraction, as well as the electrochemical dealloying process created surface defects with abundant active sites. The prepared Pt₁Cu₂ AAs catalysts with optimal strain effects and accessible surface sites displayed much-enhanced mass activity and specific activity of 1.65 A/mg_Pt and 3.96 mA/cm², which are higher than those of the Pt₁Cu₁ AAs, Pt₁Cu₃ AAs and commercial Pt/C catalysts, respectively, originating from the optimal strain effect with the moderate degree of lattice shrinkage. Meanwhile, Pt₁Cu₂ AAs displayed a remarkable stability. This work offers a new strategy to design an efficient ORR electrocatalyst with surface strain and defects by controlling atomic compositions and electrochemical dealloying process for PEMFCs.