Pt-Ni Alloy Nanoparticles via High-Temperature Shock as Efficient Electrocatalysts in the Oxygen Reduction Reaction

Exploring effective synthetic protocols for electrocatalysts of the oxygen reduction reaction (ORR) is vital to the practical application of alkaline fuel cells. Herein, a high-temperature shock (HTS) method is used to synthesize Pt-Ni alloy nanoparticles with various Pt/Ni ratios on a carbon support. The shock is provided by the Joule effect of current passing through the carbon paper. The ultrafast quenching process after the second-long current endows the as-synthesized alloy with an adjustable size and kinetically trapped dislocation features, which provides a degree of structure tuning toward electrocatalysts with improved ORR performance. Among the series of catalysts with various compositions, catalysts with a Pt/Ni ratio of 1 display a half-wave potential of 0.9 VRHE with a corresponding specific activity of 0.87 mA cm(-2), roughly 6-fold that of the commercial Pt/C catalyst. The half-wave potential shows a limited negative shift after 5000 cycles of the durability test, proving the feasibility of fabricating carbon-supported Pt alloy catalysts from HTS with remarkable ORR activity and stability. The influence of composition and strain on the performance is investigated by the density-functional theory calculation.

Automated summary

This study successfully synthesized carbon-supported Pt-Ni alloy nanoparticles using the high-temperature shock method. The alloy exhibited adjustable size and kinetically trapped dislocation features, allowing for structure tuning towards improved ORR performance in electrocatalysts. Among the catalysts, those with a Pt/Ni ratio of 1 displayed higher half-wave potential and significantly enhanced specific activity. The influence of composition and strain on the performance was investigated using density-functional theory calculations.