Atomic controlled shell thickness on Pt@Pt 3 Ti core-shell nanoparticles for efficient and durable oxygen reduction

The exploitation of durable and highly active Pt-based electrocatalysts for the oxygen reduction reaction (ORR) is essential for the commercialization of proton exchange membrane fuel cells (PEMFCs). Herein, we designed Pt@Pt 3 Ti core-shell nanoparticles with atomic-controllable shells through precise thermal diffusing Ti into Pt nanoparticles for effective and durable ORR. Combining theoretical and experiment analysis, we found that the lattice strain of Pt 3 Ti shells can be tailored by precisely controlling the thickness of Pt 3 Ti shell in atomic-scale on account of the lattice constant difference between Pt and Pt 3 Ti to optimize adsorption properties of Pt 3 Ti for ORR intermediates, thus enhancing its performance. The Pt@Pt 3 Ti catalyst with one-atomic Pt 3 Ti shell (Pt@1L-Pt 3 Ti/TiO 2 -C) demonstrates excellent performance with mass activity of 592 mA mg Pt -1 and durability nearly 19.5-fold that of commercial Pt/C with negligible decay (2 %) after 30,0 0 0 potential cycles (0.6-1.0 V vs. RHE). Notably, at higher potential cycles (1.0 V-1.5 V vs. RHE), Pt@1L-Pt 3 Ti/TiO 2 -C also showed far superior durability than Pt/C (9.6 % decayed while 54.8 % for commercial Pt/C). This excellent stability is derived from the intrinsic stability of Pt 3 Ti alloy and the confinement effect of TiO 2 -C. The catalyst's enhancement was further confirmed in PEMFC configuration. (c) 2024 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.