Adsorption and decomposition mechanisms of <scp>CO</scp>  + Cl ₂ and <scp> COCl ₂ </scp> on <scp>MgO</scp> (100) surface: A <scp>DFT</scp> study

Abstract Density functional theory (DFT) was employed to investigate the adsorption and reaction of CO + Cl₂ mixture and phosgene on the perfect MgO (100) surface and defect surface with neutral Schottky pair defects. The O atom exhibits a high energy‐level matching with Cl₂, catalyzing its dissociation, while defects enhance both the catalytic and adsorption capabilities. Mg atoms adsorbed Cl₂ and CO through electrostatic interactions, providing binding sites for Cl atoms in the conversion of CO+ Cl₂ and COCl₂ to CO₂. COCl₂ adsorbed parallel on perfect MgO surface with bond lengths slightly increase, and this catalytic effect led to a low decomposition barrier (+0.01 eV). Defects could either enhance the stability of COCl₂ or promote its decomposition, depending on adsorption configuration. Additionally, a stable intermediate, COOCl, was identified in the decomposition process of harmful gas. These findings contributed to a deeper understanding of the adsorption and transformation of chlorine‐containing exhaust gases on MgO surfaces, highlighting the potential applications of MgO in gas purification.