Ti Single Atom Enhancing Pt‐Based Intermetallics for Efficient and Durable Oxygen Reduction

Abstract

AbstractThe insufficient durability of Pt‐based catalysts and the sluggish kinetics of oxygen reduction reaction (ORR) is hampering the development of proton exchange membrane fuel cells (PEMFCs) for commercialization. Herein, a single atom Ti‐modified activated nitrogen‐doped porous carbon (Ti‐a‐NPC) is designed to equalize O2‐activation/*OH‐removal through regulating the charge rearrangement of ultra‐small L12‐Pt3Co for efficient and durable oxygen reduction. The Ti single‐atom modified in the surface/pore of Ti‐a‐NPC can anchor the Pt‐based intermetallic nanoparticles (NPs) not only guarantees Pt‐based intermetallics’ ultra‐fine size (≈2.62 nm) but also maintains Pt‐based intermetallics during ORR process. The enhanced catalyst (L12‐Pt3Co/Ti‐a‐NPC) achieves 11‐fold mass activity (1.765 A mgPt−1) compared to commercial Pt/C. Notably, after 30 000 cycles of accelerated durability tests, the mass activity of the L12‐Pt3Co/Ti‐a‐NPC only decreased by 3.7%, while that of commercial Pt/C decreased by 37.1%. Rationalized by theoretical simulation, the introduction of Ti atoms can form charge channels between L12‐Pt3Co NPs and Ti‐a‐NPC, accelerating the charge transfer in the ORR process. Furthermore, the charge of L12‐Pt3Co will accumulate to Ti atoms and buffer the electron transfer of L12‐Pt3Co to the N atoms, thus optimizing the adsorption performance of the active site to the oxygen‐containing intermediate and improving the intrinsic activity of the catalyst.