Theoretical Study on the Activation of CO₂ at the Ni/Al₂O₃ Interface under External Electric Field

The interface between metal supports plays a crucial role in many multiphase catalytic processes and has received widespread attention, but research on interface interactions under external electric fields is still far from sufficient. In this paper, the activation of CO₂ on the surface and interface of catalyst model Ni_n/Al₂O₃(n = 1-7,9) under positive electric field (+0.6 V/Å), zero electric field (0 V/Å), and negative electric field (-0.6 V/Å) was studied by means of periodic calculation and construction microkinetic models by density functional theory. Under the three electric fields, the adsorption energy of CO₂ at the interface and surface is negative electric field > zero electric field > positive electric field. We found that the negative electric field can further improve the adsorption performance of CO₂. In addition, we explored that CO₂ tends to bind at the Ni-Al interface rather than the metal surface under the three electric fields, and the applied electric field has a greater effect on the adsorption of CO₂ on the cluster interface. We also explored that the strength of the external electric field is related to the zero-field dipole moment of the adsorbed species. It is hoped that our present work can help people to understand the effects of external electric fields and interfaces on CO₂ activation better, thus improving the catalyst for CO₂ hydrogenation reactions.