High-Performance Intermetallic Pt3Co/C Electrocatalyst for the Oxygen Reduction Reaction Synthesized by Pre-Lithiation Method.

Fuel cells are recognized as promising alternatives to existing conventional energy systems for a sustainable future. However, the synthesis of efficient and robust platinum (Pt) based catalysts remains a challenge for practical fuel cell applications. Herein, the Pt₃Co/C nanoparticles with about 4.45 nm are firstly prepared by a "pre-lithiation-deposition" strategy on C carrier and used as efficient electrocatalysts for cathodic oxygen reduction reaction. Notably, after heat treatment at 600 °C, the obtained Pt₃Co/C-600 catalyst shows excellent mass and specific activities (MA and SA) of 0.69 A mg  ${}_{Pt}^{-1}$ and 1.01 mA cm  ${}_{Pt}^{-2}$ , respectively, which are more than one order of magnitude higher than that of Pt/C-600. In particular, after accelerated durability testing with 20k cycles, the durability of the Pt₃Co/C-600 catalyst (98.3 % retention of MA) is much higher than that of Pt₃Co/C-600 without pre-lithiation (42.5 % retention of MA). The alloying of Pt and Co and the use of "pre-lithiation" to enable strong interactions between the carbon carriers and the Pt-Co nanoparticles contributed to the increased activity and excellent stability. This work provides a new perspective for the development of high-performance and low-cost Pt alloy electrocatalysts.