Dissociation of CO2 on rhodium nanoclusters (Rh13) in various structures supported on unzipped graphene oxide – a DFT study

Abstract

The catalytic activity of rhodium nanoclusters (Rh₁₃) on unzipped graphene oxide (Rh₁₃/UGO) has been investigated for comparison with Rh₁₃ nanoclusters and Rh(111) surfaces. The binding energy of Rh atoms on UGO is less than the cohesive energy (−5.75 eV) of bulk Rh, indicating that the Rh atoms adsorbed on UGO tend to collect into clusters. We systematically calculated the adsorption energies of CO₂ on Rh₁₃ nanoclusters in various stable shapes on unzipped graphene oxide; Rh₁₃-I_h/UGO had the highest energy (where the I_h represents icosahedral shape), −1.18 eV, with the C–O bond being elongated from 1.17 to 1.29 Å; the barrier to dissociation of CO₂ on Rh₁₃-I_h/UGO is, accordingly, the smallest (E_a = 0.45 eV), indicating that Rh₁₃-I_h/UGO might act as an effective material to adsorb and activate the scission of the C–O bond of CO₂. The calculated data required to support all evidence of this result, including the electronic distribution and the density of states, are provided.