CO2 adsorption behaviour on β-C2S(111) and (100) surfaces: Implications for carbon sequestration in cementitious materials

• CO2 adsorption is more energetically favorable on the β-C2S(111) surface than on the β-C2S(100) surface, with adsorption energies of –0.647 eV and –0.423 eV, respectively. • H2O adsorption on β-C2S(111) is significantly stronger than CO2 adsorption (–1.588 eV vs. –0.647 eV), indicating that hydration occurs preferentially before carbonation. • Electronic structure analyses reveal that Ca and O sites on the β-C2S(111) surface exhibit higher chemical reactivity for CO2 adsorption, as evidenced by changes in valence electron counts. • The findings provide a theoretical basis for designing cementitious materials with enhanced CO2 capture and storage capabilities, contributing to carbon sequestration strategies.