CO2 Activation on Ni/γ-Al2O3 Catalysts by First-Principles Calculations: From Ideal Surfaces to Supported Nanoparticles

Due to the impact of anthropogenic CO2 emissions on global warming, the conversion of this molecule to useful products is of increasing interest. Therefore, further understanding of the CO2 activation is needed. Ni-based catalysts are able to dissociate and convert CO2 into fuels, and although these systems are generally simulated using simple slab models, real catalysts are significantly more complex. They are generally composed of nanoparticles supported on oxides, being gamma-Al2O3 one of the most widely used supports. In this study, we perform ab initio simulations in order to model the CO2 activation on Ni nanoparticles supported on gamma-Al2O3. Starting from ideal surface terminations, going to Ni nanoparticles (0.5-1 nm) and up to gamma-Al2O3 supported Ni nanoparticles, the role of terraces, steps, edges, and the support is evaluated for this chemical transformation. The metal oxide interface provides the most active sites for CO2 activation, due to a synergistic effect between the nickel nanoparticles and the Lewis acidic sites of gamma-Al2O3.