Growth and Characterization of Crystalline Metal Nanoparticles on h-BN

The development and characterization of novel composites consisting of ordered arrays of monodisperse size nanoparticles supported on a substrate is a hot topic in materials science. Here, a 2D material consisting in a pseudo-ordered distribution of Ir nanocrystals supported on the h-BN/Rh(111) interface will be presented. The deviations of nanoparticles positioning with respect to a perfect periodic arrangement can be tuned by the temperature and the amount of Ir. Upon annealing, this material undergoes slight structural changes in the temperature range 370-570 K and much more drastic ones, which are due to cluster coalescence, between 670 and 770 K. This relatively high onset of coalescence is encouraging for using this 2D material as a catalyst for reactions as the oxidation of CO or of NO by molecular oxygen, which are especially relevant in the field of environmental science. From this material, metal nanostructures, exhibiting regular geometries have been created by using the STM tip. Because of the insulating character of h-BN, these nanostructures could be very promising to design conductive nanotracks.