Ru/Active Carbon Catalyst: Improved Spectroscopic Data Analysis by Density Functional Theory

Abstract

We describe a DFT study on the self-organizing of ruthenium (Ru) nanoparticles deposited on a sp2 carbon layer (either of graphite type or of graphene type) using cluster models. The calculations provide insights into the nature and structure of the supported Ru clusters and the active sites of B5-type. Different sizes of Ru nanoparticles have been tested with up to 17 atoms. The carbon support has been modeled using a single sp2 carbon layer (graphene type) and double sp2 carbon layer (graphite type). Our DFT results suggest that for clusters with more than 4 Ru atoms, epitaxial growth of Ru on the carbon support is possible only in certain configurations. We were able to build and stabilize three-dimensional Ru nanoparticles with several B5-type active sites on the carbon support. Such C-supported Ru-nanoparticles exhibiting B5-type sites give potential for further molecule adsorption and reaction mechanism studies. The all investigated structures and configurations for different Ru nanoparticles are presented. The supported Ru nanoparticles have been used for interpreting valence band and EXAFS spectra of a commercial Ru/activated carbon catalyst. The Ru nanoparticles supported on graphene gives the best interpretation of the spectroscopic data.