Ab initio calculations of CO2 adsorption on β-C2S(100) and M3-C3S(001) surfaces: An exploration of early CO2 sequestration pathways

Chongchong Qi; Xinhang Xu; Jie Chen; Li Guo; Qiusong Chen

doi:10.1016/j.envres.2022.114412

Ab initio calculations of CO₂ adsorption on β-C₂S(100) and M3-C₃S(001) surfaces: An exploration of early CO₂ sequestration pathways

Environ Res. 2022 Dec;215(Pt 2):114412. doi: 10.1016/j.envres.2022.114412. Epub 2022 Sep 23.

Authors

Chongchong Qi¹, Xinhang Xu², Jie Chen³, Li Guo², Qiusong Chen⁴

Affiliations

¹ School of Resources and Safety Engineering, Central South University, Changsha, 410083, China; School of Molecular Science, University of Western Australia, Perth, 6009, Australia. Electronic address: chongchong.qi@csu.edu.cn.
² School of Resources and Safety Engineering, Central South University, Changsha, 410083, China.
³ School of Resources and Safety Engineering, Chongqing University, Chongqing, 400044, China.
⁴ School of Resources and Safety Engineering, Central South University, Changsha, 410083, China. Electronic address: qiusong.chen@csu.edu.cn.

PMID: 36162466
DOI: 10.1016/j.envres.2022.114412

Abstract

Investigating CO₂ sequestration in cement-based materials is significant for achieving carbon neutrality in the cement and concrete industries. The early CO₂ sequestration pathways on cement-based materials are fundamental for CO₂ sequestration, which is not clear. Towards this, the adsorption behavior of CO₂ on β-C₂S(100) and M3-C₃S(001) was investigated at the atomic level using density functional theory calculations, which were then compared with water adsorption results. The molecular adsorption configurations of CO₂ on both β-C₂S(100) and M3-C₃S(001) were tilted from their initial configurations due to the influence of surface Ca and O atoms. The CO₂ adsorption energy on M3-C₃S(001) and β-C₂S(100) were -0.458 eV and -0.426 eV, respectively, indicating adsorption on M3-C₃S(001) was more energetically favorable. After CO₂ adsorption, electrons were transferred from the surface to the CO₂ molecule. Furthermore, the Ca-O bond orders of β-C₂S(100) and M3-C₃S(001) after CO₂ adsorption were maximally decreased by 2.79% and 6.99%, respectively. A more significant adsorption influence on surfaces was found for H₂O, with more negative adsorption energy, more evident electron transfer, and a greater decrease in bond order. The CO₂ adsorption on β-C₂S(100) and M3-C₃S(001) were still spontaneous at 298 K and 1 atm. This study provides important theoretical insights into early CO₂ sequestration at the atomic level, which has practical implications for the design of efficient CO₂ sequestration technologies.

Keywords: CO(2) adsorption; CO(2) sequestration and uptake; Calcium silicates; First-principles calculations; Portland cement.