High-Loading Pt-Co/C Catalyst with Enhanced Durability toward the Oxygen Reduction Reaction through Surface Au Modification.

Carbon-supported Pt-Co (Pt-Co/C) nanoparticles with a high Pt loading are regarded as promising cathode catalysts for practical applications of proton exchange membrane fuel cells (PEMFCs). Unfortunately, with high loading, it is difficult to improve the catalytic durability while maintaining the particle size between 2-5 nm to ensure the initial catalytic activity. Thus, it is of great significance to prepare high-loading Pt-Co/C catalysts with enhanced activity and durability. Herein, we proposed an efficient way to prepare high-Pt-loading (>50 wt.%) Pt-Co/C catalysts without using any further surfactants. Furthermore, due to the one-step selective acid etching and surface Au modification, the as-prepared catalysts only need to undergo thermal treatment at as low as 150℃ to achieve a surface structure rich of Pt and Au. The average particle size of the as-prepared Au-Pt-Co/C-0.015 is 3.42 nm and the Pt loading of it is up to 50.2 wt.%. The atomic ratio of Pt, Co and Au is 94:5:1. The mass activity (MA) is nearly 1.9 times that of Pt/C (60 wt.%, JM) and the specific activity (SA) is also improved. The MA loss after the 30,000-cycle accelerated degradation test (ADT) is only 9.4%. The remarkable durability is mainly due to the surface Au modification, which can restrict the dissolution of Pt and Co. This research provides an effective synthesis strategy to prepare high-loading carbon-supported Pt-based catalysts beneficial to practical PEMFC applications.