Facile synthesis of clean PtAg dendritic nanostructures with enhanced electrochemical properties†
Recently, great efforts have been devoted to improving the catalytic activity and durability of Pt based catalysts for proton exchange membrane fuel cells. Here, surfactant-free PtAg fractal dendritic nanocrystals (NCs) with high surface area were prepared via a facile one-pot reaction. The control synthetic experiments proved that the formation of PtAg fractal dendritic NCs resulted from a kinetics-controlled growth, i.e. the “diffusion limited aggregation” mechanism. Due to their unique structural advantage and clean surface, the as-prepared PtAg fractal dendritic NCs exhibited superior electrochemical catalytic activities and structural stabilities compared with commercial Pt black and Pt/C towards methanol electro-oxidation and oxygen reduction reaction in acidic media. The design strategy presented here may be useful in fabricating other highly active and stable Pt–M catalysts for fuel cells.