Dramatic increases in fossil fuel consumption inevitably led to the emission of huge amounts of CO₂ gas, causing abnormalities in the climate system. Despite continuous efforts to resolve global atmospheric problems through CO₂ capture and separation, success has been limited by poor CO₂ selectivity in the CO₂/N₂ mixture. Herein, we demonstrate the fabrication of a three-dimensional (3D) nanostructure from two-dimensional transition metal carbides (Ti₃C₂Tx, MXene), and assess its utility as an adsorbent in a CO₂ capture system. Through structural and textural analysis, we confirm that the as-prepared MXene possesses high size uniformity with a thickness of ~2.5 nm, and that an MXene aerogel interconnected by MXene nanosheets has a 3D porous architecture with micro/nano porosity (Barrett-Joyner-Halenda (BJH) pore size = 11.4 nm). Moreover, the MXene aerogel exhibits favorable adsorption behavior for CO₂, due to the high-quality MXene nanosheets even with a low specific surface area. Our approach could lead to significant advances in CO₂ capture by adsorbents and open up new opportunities for mass production.