Fibrous AuPt bimetallic nanocatalyst with enhanced catalytic performance

Abstract

The nature of a physicochemical process and the surface reactivity properties involving charge transfer, catalysis, adsorption, surface segregation, etc., depend on the nanocatalyst morphology, available surface area and atomic composition. In this paper, we demonstrate a simple method to synthesize AuPt bimetal nanoparticles with an exotic morphology, namely fibrous nanoparticles (FNPs), directly on an ITO substrate surface via a liquid-phase deposition approach. The AuPt FNPs are constructed with a networked nanorod (diameter ca. 3–5 nm), and its morphology resembles a cauliflower. The lattice-mismatching effect between Au and Pt is assumed as the key factor for the formation of such an exotic structure. High-resolution transmission electron microscopy analysis shows that the nanorods are bounded by (001), a high-energy facet in the fcc crystal of Au or Pt. XPS analysis revealed that the AuPt FNPs show signs of possessing a highly unstable d-electron system at the top surface of the nanocrystals, which renders a highly reactive surface for efficient catalytic and surface reaction. Examination of the catalytic properties of the AuPt FNPs in a model catalytic reaction, namely acetone hydrogenation to produce isopropyl alcohol under microwave irradiation, reveals that the AuPt FNPs effectively and selectively converted the acetone to isopropyl alcohol with TON and TOF as high as 67 × 10² and 3.5 × 10² s⁻¹, respectively. It was also found that the kinetic rate of the conversion linearly increases with increasing Au concentration in the AuPt FNPs. The mechanism of nanostructure growth and the detailed physicochemistry and catalytic properties of the AuPt FNPs will be discussed.