Bismuth oxide nanoparticles as a nanoscale guide to form a silver–polydopamine hybrid electrocatalyst with enhanced activity and stability for the oxygen reduction reaction

Abstract

Highly dispersed Ag nanoparticles (Ag NPs) were successfully synthesized on functionalized polydopamine (PDA)@Bi₂O₃ NPs for use as an electrocatalyst. In the proposed method, a uniform layer of PDA was first coated on Bi₂O₃ NPs. The surface of the PDA@Bi₂O₃ can then be used as a nanoscale guide to deposit Ag NPs and hence for the formation of Ag–PDA@Bi₂O₃ hybrid nanocatalysts. It was found that Ag NPs enhanced the electrocatalytic ability on PDA@Bi₂O₃ by a synergetic effect for direct 4e⁻ transfer in the oxygen reduction reaction (ORR) with a low overpotential. The surface morphology and lattice fringes of Ag NPs of crystalline nature of the obtained Ag–PDA@Bi₂O₃ hybrid nanocatalysts were examined through HR-TEM and SAED patterns. The material's purity and chemical functional groups were identified by FT-IR analysis. This strategy provides new opportunities to design and optimize heterogeneous nanocatalysts with tailored size, morphology, chemical configuration and supporting substrates for metal-catalyzed reactions.