Tailored Lattice Compressive Strain of Pt‐Skins by the L12‐Pt3M Intermetallic Core for Highly Efficient Oxygen Reduction

Abstract

AbstractThe sluggish kinetics of oxygen reduction reaction (ORR) and unsatisfactory durability of Pt‐based catalysts are severely hindering the commercialization of proton‐exchange‐membrane fuel cells (PEMFCs). In this work, the lattice compressive strain of Pt‐skins imposed by Pt‐based intermetallic cores is tailored for highly effective ORR through the confinement effect of the activated nitrogen‐doped porous carbon (a‐NPC). The modulated pores of a‐NPC not only promote Pt‐based intermetallics with ultrasmall size (average size of <4 nm), but also efficiently stabilizes intermetallic nanoparticles and sufficient exposure of active sites during the ORR process. The optimized catalyst (L12‐Pt3Co@ML‐Pt/NPC10) achieves excellent mass activity (1.72 A mgPt−1) and specific activity (3.49 mA cmPt−2), which are 11‐ and 15‐fold that of commercial Pt/C, respectively. Besides, owing to the confinement effect of a‐NPC and protection of Pt‐skins, L12‐Pt3Co@ML‐Pt/NPC10 retains 98.1% mass activity after 30 000 cycles, and even 95% for 100 000 cycles, while Pt/C retains only 51.2% for 30 000 cycles. Rationalized by density functional theory, compared with other metals (Cr, Mn, Fe, and Zn), L12‐Pt3Co closer to the top of “volcano” induces a more suitable compressive strain and electronic structure on Pt‐skin, leading to an optimal oxygen adsorption energy and a remarkable ORR performance.