Light-triggered molecular lever in a MOF@COF nanosheet for synergistic enhancement of heat and mass transfer in CO2 photothermal desorption

A photo-switchable NH 2 -AZO molecular lever exfoliates MOF and bridges COF growth. • Core-shell nanosheet couples light-triggered pore opening with heating. • It shows high CO 2 capacity (4.5 mmol/g at 298 K/1 bar) and selectivity (CO 2 /N 2  = 190). • It achieves 98% CO 2 desorption in 40 min with 75% lower regeneration energy. • Light-triggered transfer ends desorption tailing and concentrates CO 2 release. The CO 2 capture efficiency of solid adsorbents in CCS technology is largely determined by their regeneration efficiency. To achieve rapid and energy-efficient CO 2 adsorbents regeneration, emerging photothermal desorption technologies offer distinct advantages owing to their unique inside-out heating mechanism. However, current adsorbent materials often struggle to balance photothermal conversion efficiency and mass-transfer performance. The incorporation of photothermal components enhances energy conversion but tends to block or lengthen diffusion pathways, resulting in a mismatch between heat delivery and pore accessibility. Inspired by the light-regulated opening and closing of plant stomata, this study proposes a light-triggered synergistic intelligent mass-transfer strategy for efficient CO 2 capture and enhances photothermal desorption using a MOF@COF nanosheet composite. The key point of this strategy is the multifunctional photo-switch molecule NH 2 -AZO, which acts as a molecular lever. It induces the self-exfoliation of CALF-20 into nanosheets, thereby shortening diffusion pathways, and simultaneously facilitates the epitaxial growth of a COF photothermal shell. Furthermore, its reversible photoisomerization enables dynamic regulation of internal pore sizes. This on-demand opening mass-transfer mechanism, coupled with the high photothermal efficiency of the COF shell, substantially accelerates CO 2 diffusion during photothermal desorption.