Kelvin Probe Force Microscopy Study of a Pt/TiO2 Catalyst Model Placed in an Atmospheric Pressure of N2 Environment

A catalyst model comprising platinum nanoparticles deposited on a TiO(2)(110) wafer was prepared in a vacuum, transferred in air, and characterized with a Kelvin probe force microscope placed in a N(2) environment. The topography and local work function of individual nanoparticles were observed with single-nanometer resolution in the N(2) environment of one atmosphere pressure. Some nanoparticle presented positive shifts of work function relative to that of the TiO(2) surface, while the others showed negative shifts. This finding suggests heterogeneous properties of the nanoparticles exposed to air and then N(2). The ability of the advanced microscope was demonstrated in observing the work function of metal nanoparticles on a metal oxide support even in the presence of vapor environments.