Energy‐Coupled Crystalline Hexapodal Amine Sorbents for Low‐Energy Direct Air Capture and CO ₂ Conversion

ABSTRACT Rising atmospheric ​carbon dioxide (CO 2 ) concentrations—now above 410 ppm—threaten climate stability. While point‐source carbon capture has advanced, it cannot address diffuse legacy emissions. Direct air capture (DAC) offers a complementary approach but is hampered by the high energy cost of sorbent regeneration under ambient conditions. Inspired by biological energy coupling, we developed a DAC system that links CO 2 binding with sorbent dissolution and release with recrystallization. Using branched hexapodal amines such as 2‐PHA , the system captures CO 2 from air at 0°C and releases it at 40°C using only mechanical stirring, without significant external heating. Exothermic formation of carbamate and bicarbonate drives sorbent dissolution, storing energy that is later recovered during crystallization to power desorption. This reversible coupling enriches atmospheric CO 2 to >95% purity and integrates directly with electrocatalytic conversion. With tailored electrocatalysts, directly air‐captured CO 2 is reduced to carbon monoxide (CO) or formate with up to 99% Faradaic efficiency; the CO stream reaches 82% purity, suitable for direct use. This study introduces a generalizable design principle—coupling chemical capture with phase transitions—to minimize regeneration energy. The resulting platform is scalable, regenerable, and modular, offering a new low‐energy pathway for atmospheric CO 2 capture and utilization.