CO2 capture and dissociation on novel Ni/CaO bifunctional materials: A theoretical study

Abstract

Calcium-looping dry reforming of methane (CaL-DRM) strategy mainly relies on novel Ni/CaO-based dual-functional materials, in which its microscopic mechanism remains to be further explored. In this work, molecular simulation of the adsorption and dissociation processes of CO₂ was performed on the surface of Ni/CaO dual-functional materials (DFMs) based on density functional theory (DFT). The analyses of electron density, partial density of states, and formation energy suggest that the Ni/CaO model has higher stability and activity than the CaO model. The analyses of the evolution of chemical bonds, adsorption energy, density of states, and charge population after the adsorption of CO₂ on the CaO surface and Ni/CaO shows that the modification with Ni made the adsorption of CO₂ on Ni/CaO more stable. The transient calculations indicate that the path with the lowest activation energy is the H-mediated dissociation path of chemisorption carboxyl COOH* as an intermediate, which is the possible dissociation path of CO₂ on the surface of Ni/CaO DFMs. The dissociation of COOH* into CO* and OH* is the rate-controlling step of the reaction. The DFT results demonstrate that the doping of Ni during the preparation of CaO materials can realize and enhance the CaL-DRM processes, which provide a theoretical basis for the optimum preparation of Ni/CaO-based DFMs. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.