15920
J. Phys. Chem. B 2006, 110, 15920-15925
Carbon Monoxide Adsorption and Oxidation on Monolayer Films of Cubic Platinum Nanoparticles Investigated by Infrared-Visible Sum Frequency Generation Vibrational Spectroscopy S. J. Kweskin,†,‡ R. M. Rioux,†,§ S. E. Habas,† K. Komvopoulos,‡ P. Yang,† and G. A. Somorjai*,† Department of Chemistry, UniVersity of California, Berkeley, California 94720, and Materials Sciences DiVision, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Mechanical Engineering, UniVersity of California, Berkeley, California 94720 ReceiVed: April 19, 2006; In Final Form: June 14, 2006
The adsorption and oxidation of CO on monolayer films of cubic Pt nanoparticles synthesized by a modified solution-phase polyol process were examined by sum frequency generation (SFG) vibrational spectroscopy in total internal reflection (TIR) geometry. Extremely low incident laser power (∼5 µJ/pulse of infrared) yields sufficient SFG intensity in TIR geometry and reduces destructive interference. Because TIR-SFG spectroscopy does not require correction for bulk gas absorption, CO spectra can be collected over a wide pressure range (
