Oxygen Vacancy Mediated Carbonation of γ‐C ₂ S: Combined Ab Initio Calculations and OPES Enhanced Sampling Insights

ABSTRACT The γ‐dicalcium silicate (γ‐C 2 S) has emerged as a promising candidate material for CO 2 capture and mineralization owing to its high carbonation activity. This work systematically investigates how oxygen vacancy regulates the γ‐C 2 S carbonation process by well‐defined ab initio calculations. Our results reveal that the oxygen vacancy introduces localized charge states at the surface, which significantly activated CO 2 reaction activities. The oxygen vacancy also facilitates the dynamic leaching of surface Ca 2+ ions. The complete reaction free energy landscape was mapped by On‐the‐fly Probability Enhanced Sampling (OPES) approach, and the calculated results show that the oxygen vacancy substantially modulates the entire reaction pathway, stabilizing a key torsional transition state and lowering the kinetic energy barrier for carbonate formation. Revealing a triple synergistic mechanism that significantly influences the reaction dynamics. This work elucidates a defect‐driven kinetic control mechanism that transcends static thermodynamics, thereby establishing a dynamic framework offering critical guidance for the rational design and defect engineering of high‐activity silicate materials for advanced carbon capture applications.