New self-healing agents that can chemically bind seawater ions invading cracked cementitious materials were proposed. The potential of self-healing and binding of seawater ions were investigated by thermodynamic modeling. It was found that CaO-NaAlO₂ and CaO-metakaolin agents can have Cl⁻, SO₄²⁻ and Mg²⁺ chemically bound by reacting with sea water to form Friedel's salt, Kuzel's salt, ettringite and hydrotalcite. The removal of Cl⁻ from seawater firstly increased and then decreased with the increase of Ca/Al molar ratio in both agents, while the removal of Mg²⁺ and SO₄²⁻ were hardly influenced and approximated 100%. Because NaAlO₂ dissolves and releases Al(OH)₄⁻ rapidly, precipitates binding Cl⁻, SO₄²⁻ and Mg²⁺ were formed fast. In comparison, the reaction of metakaolin binding aggressive ions occurred after 3 days. Because of the faster reaction and the capacity to make [Cl⁻]/[OH⁻] lower in the solution, CaO-NaAlO₂ would be more efficient for self-healing and mitigating reinforcement corrossion than CaO-metakaolin.

Graphene foams are promising three-dimensional (3D) architectures with the combination of the intrinsic nature of graphene and unique cellular structures for various realms. Herein, a facile technique is developed by combining supramolecular assembly with lyophilization to functionalize graphene with donor−π-acceptor (D−π-A) molecules and then massively transform the two-dimensional (2D) plane nanosheets into 3D foams. The as-prepared gas sensors work at room temperature (RT) and reveal comprehensive gas sensing performance with an ultrahigh response (R _a/R _g = 3.2, 10 ppm), excellent selectivity, and reliable repeatability toward NO ₂. Notably, a gas sensing enhancement mechanism with density functional theory (DFT) calculations is proposed to unravel the synergetic effect of the “Greater Electron Transferring Area” and the specific 3D foam structure for the enhancement of charge transfer and NO ₂ adsorption. The combination of supramolecular assembly and the lyophilization technique provides a strategy to prepare 3D architectural graphene-based materials for high-performance gas sensors and chemical trace detectors.