CO2 activation and dissociation on the Fe2O3/Cu(111) inverse catalyst: A dispersion-corrected DFT study

Abstract

Density functional calculations have been performed to study the adsorption and dissociation of CO2 on a model of Fe2O3/Cu(1 1 1) inverse catalyst employing the PBE-D3 functional. The adsorption of the Fe2O3 cluster on Cu(1 1 1) surface was found to be highly exothermic accompanied by a noticeable deformation of its structure. An electronic charge transfer from Cu to Fe2O3 was observed and the appearance of a partially occupied Fe 4 s electronic state around the Fermi level was evidenced. This available electronic charge plays a significant role in the subsequent CO2 adsorption. This molecule adsorbs preferentially at the oxide–metal interface with a bent geometry. The adsorption involves a charge transfer from Fe2O3/Cu(1 1 1) to CO2, yielding an activated CO2δ- species. On pristine Cu(1 1 1) and Fe2O3(0001) surfaces, the CO2 adsorption is weaker, and the almost null charge transfer indicates a non-activated CO2 molecule. The dissociation of CO2 on Fe2O3/Cu(1 1 1) was calculated to be slightly exothermic, endothermic on Cu(1 1 1) and strongly endothermic on Fe2O3(0001). The activation barrier for CO2 dissociation was found to be 0.90 eV on Fe2O3/Cu(1 1 1), significantly lower than on Cu(1 1 1) and Fe2O3(0001). Our calculations show a great potential for the use of Fe2O3/Cu(1 1 1) inverse catalysts in reactions involving CO2 activation and dissociation.