Multifunctional bamboo-derived carbon aerogels as low-carbon materials for CO2 capture, thermal insulation and photothermal conversion with flame retardant property

The development of low-carbon materials has become a key research focus due to the rising CO 2 levels and global climate change. Carbon aerogels derived from renewable biomass, such as bamboo cellulose, offer promising solutions due to their high surface area, adjustable porosity, and lightweight thermal insulation properties. In this study, cellulose aerogels were synthesized by dissolving cellulose in an alkali-urea solution followed by freeze-drying. KOH-activated carbon aerogels were obtained via carbonization at 500 ℃ and activation at 800 ℃, achieving a specific surface area of 1900 m²/g, significantly higher than that of cellulose and carbon aerogels. CO 2 adsorption experiments showed that the activated carbon aerogel had a CO 2 uptake of 6.40 mmol/g at 0 ℃ and 3.54 mmol/g at 25 ℃. Isosteric heat of adsorption analysis indicated that adsorption enthalpy decreased with CO 2 uptake. The aerogel maintained 95 % of its initial adsorption efficiency after five cycles. It also exhibited excellent thermal insulation, with a 106 ℃ temperature difference at 200 ℃, photothermal properties, and fire resistance, remaining unignited after four minutes in an alcohol lamp. This study provides a paradigm for developing low-carbon materials with CO 2 adsorption, thermal insulation, photothermal, and flame retardant capabilities. • KOH activation at 800 °C following 500 °C carbonization yielded aerogels with a specific surface area of 1900 m²/g. • The CACCA achieved CO₂ uptakes of 6.40 mmol/g at 0 °C and 3.54 mmol/g at 25 °C, with decreasing adsorption enthalpy. • The aerogel retained 95 % of its initial CO₂ adsorption efficiency after five cycles. • It showed excellent thermal insulation (Δ106 °C at 200 °C), strong photothermal conversion, and superior flame resistance.