A bio-inspired sandwich-structured graphene oxide embedded with In(OH)3 to improve hydration kinetics and carbon sequestration of cement-based composites

Carbon sequestration of cement-based composites is an essential pathway towards the strategic goal of achieving carbon neutrality. However, the efficiency of cement-based composites to sequester carbon dioxide (CO 2 ) is limited. Inspired by legume structure, a sandwich-structured graphene oxide embedded with In(OH) 3 (SGOI) was synthesized to simultaneously enhance the CO 2 sequestration capacity, hydration kinetics, and mechanical performances of cement-based composites. The effect of SGOI content on the CO 2 sequestration capacity, hydration kinetics, and mechanical performances of cement-based composites was evaluated. The results show that the CO 2 sequestration, compressive strength, flexural strength, and eco-mechanical index of the hardened cement paste containing 0.03 wt% SGOI were achieved 52.55 g/kg, 105.1 MPa, 13.9 MPa, and 0.75 kgCO 2 /MPa, representing enhancements of 255.07 %, 32.70 %, 34.95 %, and 167.86 % compared to those of cement paste without SGOI, respectively. Meanwhile, the hydration reaction rate and hydration degree of cement at each stage were improved. The enhancement of these parameters is derived from the structural characteristics of SGOI, including the specific surface area (30.52 m 2 /g), interlayer distance (14.85 nm), and roughness (14.10 nm). One ton of hardened cement paste containing 0.03 wt% SGOI can sequestrate at least 31.09 kg of CO 2 within 28 days, highlighting its significant potential for promoting CO 2 neutrality.