Carbon dioxide adsorption of two-dimensional carbide MXenes

Abstract

Two-dimensional carbide MXenes (Ti ₃C ₂T _x and V ₂CT _x ) were prepared by exfoliating MAX phases (Ti ₃AlC ₂ and V ₂AlC) powders in the solution of sodium fluoride (NaF) and hydrochloric acid (HCl). The specific surface area (SSA) of as-prepared Ti ₃C ₂T _x was 21 m ²/g, and that of V ₂CT _x was 9 m ²/g. After intercalation with dimethylsulfoxide, the SSA of Ti ₃C ₂T _x was increased to 66 m ²/g; that of V ₂CT _x was increased to 19 m ²/g. Their adsorption properties on carbon dioxide (CO ₂) were investigated under 0–4 MPa at room temperature (298 K). Intercalated Ti ₃C ₂T _x had the adsorption capacity of 5.79 mmol/g, which is close to the capacity of many common sorbents. The theoretical capacity of Ti ₃C ₂T _x with the SSA of 496 m ²/g was up to 44.2 mmol/g. Additionally, due to high pack density, MXenes had very high volume-uptake capacity. The capacity of intercalated Ti ₃C ₂T _x measured in this paper was 502 V·v ^–1. This value is already higher than volume capacity of most known sorbents. These results suggest that MXenes have some advantage features to be researched as novel CO ₂ capture materials.