Adsorption of Carbon Monoxide on Dendrimer-Encapsulated Platinum Nanoparticles: Liquid versus Gas Phase

The ability of dendrimer-encapsulated platinum nanoparticles (Pt DENs) to adsorb carbon monoxide was contrasted in the gas versus liquid phases by using in situ infrared absorption spectroscopy. It was found that while only limited, weak, and reversible adsorption is possible in the gas phase, extensive and stronger adsorption occurs in the liquid phase, even when the Pt DENs are dispersed inside of the pores of a high surface-area solid. It is speculated that the dendrimer structure may collapse in the gas phase, blocking access to the Pt surface, but may expand and open up in the presence of a proper solvent.