Regulation of oxygen reduction reaction by the magnetic effect of L10-PtFe alloy

It is important to improve the oxygen reduction reaction (ORR) performance of Pt by alloying it with first-row transition metals (M: e.g., Fe, Co, Ni). It is known that the ligand, strain, and ensemble effects govern the ORR performance. However, the intrinsic magnetic characteristics of PtMs have rarely been focused on in ORR investigations. Here, we employed a hard-magnet L1(0)-ordered PtFe nanopillar film (L1(0)-PtFe NF) as model catalyst to uncover the catalyst's magnetic effect on the ORR. We report a five-fold enhancement of the catalytic efficiency of magnetized L1(0)-PtFe(M) NF compared with unmagnetized one. Further investigations demonstrate that the coverage of chemisorbed oxygen on catalyst surface, especially the primary Pt d(yz)-O-2 pi* coupling, manipulated by the catalyst's magnetic field is the key factor for the ORR regulation. This work thus paves the way for the implementation of magnetic effect towards the precise regulation in broad catalysis applications.