Peptide templated AuPt alloyed nanoparticles as highly efficient bi-functional electrocatalysts for both oxygen reduction reaction and hydrogen evolution reaction

Peptide driven metallic nanomaterials fabrication under mild conditions has become a significant research thrust recently, thanks to its capability to generate multifunctional materials with tunable electronic and catalytic properties. Herein, peptide Z1 is employed to fabricate a series of AuPt alloyed nanoparticles with different Au-to-Pt ratios. The morphology is examined by electron microscopic techniques, and well-defined peanut-shape is observed for Au33Pt67 while spherical particles are obtained for the other samples. The AuPt alloys demonstrate effective electrocatalytic activity toward both oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) and Au33Pt67 exhibits the best bifunctional electrocatalytic performance. Its ORR activity is superior than commercial Pt/C in alkaline media, verified by the positive onset potential (+1.02 V vs. RHE) and large diffusion-limited current density, while its HER activity is comparable with Pt/C, evidenced by the small overpotential at 10 mA cm−2 (−171 mV vs. RHE) and low Tafel slope. Moreover, Au33Pt67 exhibits markedly higher long-term durability than Pt/C for both ORR and HER. The excellent activity and stability for ORR and HER are ascribed to Au alloying Pt induced synergistic effects. The results highlight the advantages of using peptide to fabricate bi-functional or multiple functional electrocatalysts with desirable activity and robust stability.