Graphene substrate-mediated catalytic performance enhancement of Ru nanoparticles: a first-principles study.

The structural, energetic and magnetic properties of Ru nanoparticles deposited on pristine and defective graphene have been thoroughly studied by first-principles based calculations. The calculated binding energy of a Ru(13) nanoparticle on a single vacancy graphene is as high as -7.41 eV, owing to the hybridization between the dsp states of the Ru particles with the sp(2) dangling bonds at the defect sites. Doping the defective graphene with boron would further increase the binding energy to -7.52 eV. The strong interaction results in the averaged d-band center of the deposited Ru nanoparticle being upshifted toward the Fermi level from -1.41 eV to -1.10 eV. Further study reveals that the performance of the nanocomposites against hydrogen, oxygen and carbon monoxide adsorption is correlated to the shift of the d-band center of the nanoparticle. Thus, Ru nanoparticles deposited on defective graphene are expected to exhibit both high stability against sintering and superior catalytic performance in hydrogenation, oxygen reduction reaction and hydrogen evolution reaction.