Electrocatalyst on insulating support? Hollow silica spheres loaded with Pt nanoparticles for methanol oxidation

Ambrose A. Melvin, Vrushali S. Joshi, Durgasha C. Poudyal, Deepa Khushalani, Santosh K. Haram

Research output: Contribution to journalArticlepeer-review

58 Scopus citations

Abstract

Electrocatalytic oxidation of methanol on silica hollow spheres, loaded with platinum nanoparticles (Pt-SiO2-HS), is reported. The functionalized hollow silica spheres were prepared by the surfactant (lauryl ester of tyrosine) template-assisted synthesis. These spheres were loaded with platinum nanoparticles by γ-radiolysis. Energy-dispersive X-ray analysis (EDAX) and X-ray photoelectron spectroscopy (XPS) analyses confirmed presence of Si and Pt in the composite. High-resolution transmission electron microscopy showed the formation of uniformly deposited Pt nanoparticles over the hollow spheres with a predominant Pt(111) lattice plane on the surface. In spite of the poor conducting nature of the silica support, the oxidation potential and current density per unit mass for methanol oxidation were noted to be ca. 0.72 V vs NHE and 270 mA mg-1, respectively, which are among the best values reported in its class. The composite did not show any sign of a degradation even after repeated use. In fact, the anodic current was found to increase under constant polarization, which is attributed to a facile reaction between adsorbed CO with a surface hydroxyl group present on the silica support. These results are in favor of Pt-SiO2-HS as a promising electrocatalyst material in the direct methanol fuel cell (DMFC) applications.

Original languageEnglish
Pages (from-to)6590-6595
Number of pages6
JournalACS applied materials & interfaces
Volume7
Issue number12
DOIs
StatePublished - 1 Apr 2015
Externally publishedYes

Keywords

  • Pt nanoparticle
  • direct methanol fuel cell
  • electrocatalysis
  • methanol oxidation
  • silica hollow spheres
  • γ-radiolysis

ASJC Scopus subject areas

  • General Materials Science

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