TUNNELING PROBE MANIPULATION OF INDIVIDUAL RHODIUM NANOPARTICLES SUPPORTED ON TIO2

Active metals finely dispersed on oxide supports are useful in a broad class of applications. We have used scanning tunneling microscopy (STM) to characterize and to manipulate 30-50-angstrom rhodium particles grown on TiO2(001) rutile. Tunneling barrier height values of almost-equal-to 5 eV (close to the mean tip-sample work function) indicated a good vacuum tunneling gap. The tunneling probe was used to manipulate individual nanoparticles via intimate tip-sample point contacts. The results are consistent with cohesive/adhesive tip-particle interactions. This study indicates that supported catalyst and sensor research can be done on a particle-by-particle basis.