Surface enhanced sum frequency generation of carbon monoxide adsorbed on platinum nanoparticle arrays

Abstract

Sum frequency generation (SFG) provides a method for studying model nanoparticle catalyst. Without surface enhancement, the vibrational spectra of adsorbates would be unattainable on such systems. The local coverage of CO on the platinum particles is studied with SFG vibrational spectroscopy at 1 at pressure on Pt nanoparticle arrays. The Pt arrays are prepared using electron beam lithography to produce particles with uniform spacing and sizes on an oxidized Si(100) wafer. SFG signal is enhanced at small Pt particles due to the interaction of the light with the surface plasmons. The enhanced signal allows the study of catalytic reactions on model nanoparticle surfaces under reaction conditions.