Hydrotalcites (HTlcs) or layered double hydroxides (LDHs) have been used in a wide range of applications such as catalysis, electrochemical sensors, wastewater treatment, and carbon dioxide (CO 2 ) capture. In the current study, molecular dynamics simulation was employed to investigate carbon dioxide adsorption behavior on amorphous layered double oxides (LDOs) derived from LDHs at elevated temperatures. The thermal stability of LDHs was first examined by heating the sample up to T = 1700 K. Radial distribution functions confirmed the structural evolution upon heating and the obtained structures were in good agreement with experiments, where periclase was confirmed to be the stable phase in the recrystallized mixed oxides above T = 1200 K. Further, CO 2 adsorption was studied as a function of amorphous HTlc-derived oxide composition, where static and dynamic atomistic measures have been employed to characterize the CO 2 adsorption behavior. The simulation results showed that the CO 2 dynamic residence time on LDH-derived LDOs was sensitive to the Mg/Al molar ratio and the average amount of residence time of CO 2 on the surface of LDOs reached maximum when the Mg/Al molar ratio was equal to 3.0. Meanwhile, the activation energy for diffusion also showed local maximum when the Mg/Al molar ratio was 3.0, suggesting that this particular ratio of Mg/Al mixed oxides possessed the highest CO 2 adsorption capacity. This is consistent with experimental results. Examination of the binding between CO 2 and mixed oxides revealed that both magnesium and oxygen in amorphous LDOs contributed to CO 2 adsorption. Further analysis suggested that the interaction between Mg–O and O(LDO)–C were the most important interactions for the physisorption of CO 2 on amorphous surface and different CO 2 adsorption behavior on different Mg/Al molar ratio surfaces was directly related to their amorphous local structure.

a Key laboratory of Materials Modification by laser, ion, and electron Beams (Ministry of education), School of Materials Science and engineering, Dalian university of technology, Dalian, P.r. china; b School of Materials Science and engineering, tsinghua university, Beijing, P.r. china ABSTRACT The interatomic potential for Fe-Cr-Ni-N system based on the second nearest-neighbour modified embedded-atom method has been developed in this work. The potential is based on those for the corresponding lower order systems. The potential parameters for the binary systems, Cr-N, Ni-N, Ni-Fe and Ni-Cr, were determined by fitting the lattice constants, elastic properties, heat of solution and defect binding energies. The potential parameters for the ternary systems were calculated based on the corresponding binary systems. Then, all of them were applied to the quaternary system Fe-Cr-Ni-N to confirm their validity by a simulation of the lattice constants of AISI 316 austenitic stainless steel with a range of nitrogen content. The results were in good agreement with the previous observations and calculations.

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