Pyridinic-N-Rich nanoporous carbon for ultrafast solar atmospheric water harvesting

Adsorption-based atmospheric water harvesting (AWH) offers a promising route to alleviate freshwater scarcity, yet many adsorbents suffer from sluggish uptake and energy-intensive regeneration under solar operation. Nitrogen-rich porous carbons offer a platform to mitigate both challenges through enhanced water affinity and photothermal-assisted release. However, how localized electronic polarization associated with nitrogen coordination motifs and micropore architecture jointly regulate water uptake and release kinetics remains insufficiently understood. Herein, we establish a mechanism-anchored design strategy that couples computational screening with synthesis and validation to co-optimize nitrogen coordination environments and micropore architecture across a C_xN_y series. Motif-resolved electrostatic descriptors and GCMC-derived adsorption thermodynamics are linked to transport kinetics assessed by MD/DFT and time-resolved sorption experiments under energy-constrained cycling. Guided by this strategy, C₂N is identified and experimentally validated to exhibit rapid water uptake (reaching 90% of its equilibrium uptake within 55 min) and efficient one-sun regeneration (>99% release within 15 min). Outdoor tests further demonstrate multicycle operation over three consecutive days under naturally varying low-humidity conditions. The combined computational and experimental results help clarify how localized electronic polarization at nitrogen sites and accessible micropore architecture affect rapid-cycling AWH and may provide useful guidance for the future development of carbon-based sorbents for solar-driven water harvesting.