Quantitative analysis of hydrogen adsorbed on Pt particles on SiO2 in the presence of coadsorbed CO by means of L3-edge X-ray absorption near-edge structure spectroscopy

X-ray absorption near-edge structure (XANES) spectra at the Pt L₃-edge for Pt particles supported on SiO₂ under CO adsorption and CO+H₂ coadsorption were recorded to analyze the amount of adsorbed hydrogen in the coadsorbed state on the Pt particles. Adsorbed CO on the Pt particles revealed a new peak at 6 eV above the Pt L₃-edge in the difference spectra before and after CO adsorption in the coverage range 0.10-0.51. Subsequent adsorption of hydrogen at various coverages on the CO-preadsorbed Pt particles broadened and shifted the peak to the higher energy side. The peak was deconvoluted to two components due to adsorbed hydrogen and CO by a linear least-squares fitting technique. It was found that the fitting coefficient with respect to adsorbed hydrogen was proportional to the amount of adsorbed hydrogen. The XANES difference spectra provide a quantitative analysis method for adsorbed hydrogen on supported Pt particles in the presence of coadsorbates like CO. This revised version was published online in July 2006 with corrections to the Cover Date.