Ferromagnetic L12‐Pt3Co Nanowires with Spin‐Polarized Orbitals for Fast and Selective Oxygen Reduction Electrocatalysis

Magnetic alloys are key to develop efficient catalysts for oxygen reduction reaction (ORR) in fuel cells. During the last decade, it has been shown that spin manipulation of magnetic materials can improve the kinetics of triplet state 3O2 electrocatalysis, promoting the unification between the physics of strongly correlated materials and heterogeneous catalysis. In this study, structurally ordered Pt3Co nanowires (NWs) are synthesized, and their ORR catalytic performances are studied in detail. These intermetallic ordered L12‐Pt3Co NWs exhibit stronger ferromagnetism, superior ORR catalytic activity, and higher tolerance to carbon monoxide than related disordered A1‐Pt3Co NWs, and commercial Pt/C catalyst. These characteristics make them one of (if not) the best catalyst reported nowadays. Density functional theory calculations prove that the L12‐Pt3Co(111) surface displays a lower activation barrier at the ORR rate‐limiting step and better selectivity H2O2/H2O (i.e., lower production of H2O2) compared with disordered A1‐Pt3Co(111). ORR reactivity increases with the level of Co order in the slab. Moreover, L12‐Pt3Co(111) displays more favorable thermodynamics, decreasing the adsorption enthalpies of 3O2, and lower ORR rate‐limiting step, due to ferromagnetic quantum spin exchange interactions (QSEI), compared with Pt(111). Recently synthesized ordered L12‐Pt3Co nanowires exhibit better ORR catalytic activity than disordered A1‐Pt3Co nanowires, solid Pt3Co, and a commercially available Pt/C catalyst with very low production of unwanted side‐product H2O2, in‐line with that of commercial Pt catalysts. Ferromagnetic long‐range quantum spin exchange interactions (QSEI) are responsible for enhanced reactivity in L12‐Pt3Co nanowires.