Multimetallic Au/FePt₃ Nanoparticles as Highly Durable Electrocatalyst

Abstract

We report the design and synthesis of multimetallic Au/Pt-bimetallic nanoparticles as a highly durable electrocatalyst for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells. This system was first studied on well-defined Pt and FePt thin films deposited on a Au(111) surface, which has guided the development of novel synthetic routes toward shape-controlled Au nanoparticles coated with a Pt-bimetallic alloy. It has been demonstrated that these multimetallic Au/FePt(3) nanoparticles possess both the high catalytic activity of Pt-bimetallic alloys and the superior durability of the tailored morphology and composition profile, with mass-activity enhancement of more than 1 order of magnitude over Pt catalysts. The reported synergy between well-defined surfaces and nanoparticle synthesis offers a persuasive approach toward advanced functional nanomaterials.

Understanding the electrocatalysis of oxygen reduction on platinum and its alloys

“…For instance, Pt on FeAu/C only lost $7% of its initial ORR activity when cycled 60 000 times between 0.6 and 1.1 V in an RDE experiment; 179 Pt on AuPd/C only lost 37% of its initial ORR activity when cycled 100 000 times between 0.6 and 1 V in a PEMFC. 181 The high stability of these catalysts could be due to (a) the decoration of steps or other defects on Pt with Au, preventing their dissolution, 141 (b) that subsurface oxide formation is inhibited by the presence of Au or Ir in the subsurface layer 179,184 and (c) the dissolution of Pd from the core, causing a contraction of the Pt overlayer and a decreased propensity towards dissolution. 181 Future progress in the development of these novel nanostructures would be to substantially increase their mass activity, normalised to total platinum group metal content (rather than the platinum metal content), and to prepare them using a synthesis method amenable towards industrial scale-up.…”

Electrochemical preparation and characterization of PdPt nanocages with improved electrocatalytic activity toward oxygen reduction reaction

“…4a), the nanocages were built by the connection of nanoparticles and nanobars which were larger than that of Pt nanoparticles of Pt/C and shell of Pd@Pt NDs, resulting in lower amount of low-coordinated Pt atoms on the surface of NCs (i.e., smoother), because the percentage of low-coordinated Pt atoms decreases with the increase of particle size [45,46]. It is well known that these low-coordinated Pt atoms have higher oxygen binding energies which is adverse to the ORR activity [47]. As a result, the PdPt NCs showed the highest ORR activity.…”

Graphitic C3N4-Pt nanohybrids supported on a graphene network for highly efficient methanol oxidation

“…Pt becomes unstable when exposed to hostile electrochemical environments, where Pt surface atoms migrate and agglomerate, resulting in aggregation of nanoparticles and loss of surface area and activity [34,35]. In particular, the instability of Pt at the anode side represents one of the main limitations for commercialization of this technology.…”