Polyethyleneimine modified AuPd@PdAu alloy nanocrystals as advanced electrocatalysts towards the oxygen reduction reaction

摘要

Designing the low cost,active,durable,and alcohol-tolerant cathode catalysts towards the oxygen reduction reaction (ORR) is significant for the large-scale commercialization of direct alcohol fuel cells.Recently,Pd-based nanocrystals have attracted attention as Pt-alternative cathode catalysts towards the ORR in the alkaline electrolyte.Unfortunately,the pristine Pd-based nanocrystals lack the selectivity towards the ORR due to their inherent activity for the alcohol molecule oxidation reaction in the alkaline electrolyte.In this work,polyethyleneimine (PEI) modified AuPd alloy nanocrystals with Au-rich AuPd alloy cores and Pd-rich PdAu alloy shells (AuPd@PdAu-PEI) are successfully synthesized using a traditional chemical reduction method in presence of PEI.The rotating disk electrode (RDE) technique is applied to evaluate the ORR performance of AuPd@PdAu-PEl nanocrystals.Compared with commercial Pd black,AuPd@PdAu-PEI nanocrystals show significantly enhanced activity and durability towards the ORR,and simultaneously exhibit particular alcohol tolerance towards the ORR in the alkaline electrolyte.