Peptide templated Au@Pd core-shell structures as efficient bi-functional electrocatalysts for both oxygen reduction and hydrogen evolution reactions

Bimetallic core-shell nanostructures have been gaining considerable research attentions recently, mainly thanks to their versatile applications in many fields, including catalysis, electrocatalysis, electronic, sensing and so on. Herein, we demonstrate a peptide templated Au@Pd core-shell structure for both oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER). By employing peptide sequence FlgA3 as surface capping agent, core-shell structure with Pd nanoparticles coated on the surface of Au nanoparticles were prepared. The Au@Pd core-shell structures demonstrated effective electrocatalytic activities toward both ORR and HER, whereas the catalytic activity was optimized by tuning the Pd-to-Au ratio. Among a series of samples tested, we discovered that the Au@Pd 1.0 sample exhibited the best ORR activity, superior to that of Pt/C and Pd/C, while its HER activity was also among the finest, close to that of Pt/C and Pd/C. The Au@Pd 1.0 sample also exhibited remarkable stability beyond Pt/C and Pd/C in both ORR and HER. Such intriguing electrocatalytic performances are attributed to the core-shell structure induced lattice strain. The results offer reliable pathway for designing peptide templated core-shell bimetallic nanostructures as dual or multiple functional electrocatalysts with excellent electrocatalytic activities and longevity.