Sustainable Microporous Carbon Derived from Defatted Cotton Waste for High‐Performance CO₂ Capture

The increasing atmospheric CO 2 concentration necessitates the development of efficient carbon capture and storage (CCS) technologies to mitigate climate change. Porous carbon materials are promising candidates for CO 2 adsorption due to their high surface area, tunable pore structures, and chemical stability. However, the high cost and environmental impact of conventional precursors limit their large‐scale application. Herein, a sustainable and cost‐effective synthesis of microporous carbon materials derived from defatted cotton waste (DCW), an underutilized byproduct, via a simple activation process is reported. The optimized material (DCW‐700‐3) exhibits exceptional CO 2 adsorption capacities of 4.55 mmol g −1 at 25 °C and 6.81 mmol g −1 at 0 °C under 1 bar, owing to its well‐developed microporous structure, high ultramicropore volume, and oxygen‐containing surface functional groups. Furthermore, DCW‐700‐3 demonstrates excellent CO 2 /N 2 selectivity (56), moderate isosteric heat of adsorption (19–45 kJ mol −1 ), and outstanding cyclic stability with less than 2% capacity loss over five cycles. By valorizing DCW, this work not only offers a sustainable and eco‐friendly pathway for industrial‐scale CCS but also addresses global waste management challenges, aligning with circular economy and sustainable development principles.