The Rh–In bimetallic nanoparticle formation regularities: insights from theoretical and experimental studies by XPS and STM

Abstract

The formation patterns of bimetallic Rh–In nanoparticles deposited on highly oriented pyrolytic graphite (HOPG) have been studied using a combination of scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) techniques. Indium deposition on a monometallic Rh/HOPG matrix is shown to lead to the formation of bimetallic nanoparticles with a Rh_core–In_shell structure. Subsequent heating of the prepared model Rh–In/HOPG sample at a temperature of 350 °C under ultra-high vacuum conditions led to a uniform metal distribution throughout the volume of the nanoparticles. In addition, the surface morphology of the Rh–In/HOPG catalyst and the structure of the bimetallic nanoparticles were theoretically modeled based on experimental XPS and STM data.