Ab Initio Insights into the Interfacial Interactions of Emerging Two-Dimensional Nanomaterials with C‑A-S‑H...

The development of sustainable construction materials has positioned geopolymer concrete as a promising alternative to conventional Portland cement due to its reduced carbon footprint and utilization of industrial byproducts. In this context, two-dimensional (2D) materials have emerged as versatile reinforcing fillers that enable the precise tuning of interfacial interactions, thereby improving the mechanical and physicochemical performance of geopolymer systems. Herein, we present a systematic first-principles investigation of a diverse class of two-dimensional (2D) materials, including Xenes (silicene, germanene, stanene, arsenene, tellurene, and blue phosphorus), transition metal dichalcogenides (MoS₂ and WS₂), MXenes, graphene derivatives (including graphdiyne), and ceramic/covalent systems such as SiC, boron phosphate, boron nitride, and CrO₂ by examining their interfacial interactions with a structurally ordered calcium aluminosilicate hydrate (C-A-S-H) model using density functional theory (DFT). DFT-guided calculations reveal a clear hierarchy in interfacial binding, ranging from strong chemisorption (≈-1.5 to -4.0 eV) for MXenes and functionalized graphene derivatives, to moderate interactions (≈-0.8 to -1.5 eV) for Xenes and carbides, and weak physisorption (≈-0.2 to -0.8 eV) for transition metal dichalcogenides (TMDs) and ceramic surfaces. MXenes and functionalized graphene exhibit the strongest adhesion, driven by covalent bonding, Ca²⁺ mediated bridging, and charge transfer, leading to improved load transfer and microstructural densification. In contrast, graphdiyne and h-BN are dominated by van der Waals interactions, contributing mainly to durability and stability. Overall, this study establishes that surface functionality and electronic structure govern interfacial strength and reinforcement efficiency in 2D material-geopolymer systems. Therefore, this DFT-guided comparative study establishes a unified structure-interaction-property relationship and highlights that surface functionality and electronic structure are the key descriptors governing reinforcement efficiency. The findings establish clear design principles for the rational selection of 2D reinforcements, positioning MXenes, Xenes, and functionalized graphene as leading candidates for the development of next-generation, high-performance, and durable geopolymer concretes.