Bioinspired Hierarchically Interconnected Supermacroporous Hydrogels via Dual‐Templating for Rapid Atmospheric Water Harvesting

ABSTRACT Hydrogel sorbents for atmospheric water harvesting (AWH) require simultaneously rapid vapor transport and structural stability. However, the narrow and tortuous pore networks in conventional hydrogels cause diffusion‐limited kinetics and pore collapse, making the transport–stability trade‐off a key challenge in hydrogel sorbent design. Inspired by the hierarchically interconnected architecture of lung alveoli for rapid and durable gas exchange, we develop a dual‐template pore‐engineering strategy that integrates in situ CO ₂ bubbles with ice templating to construct robust supermacroporous hydrogels with multiscale interconnected pathways. CO ₂ bubbles generate millimeter‐scale cavities as “alveolar sacs” for enhanced air accessibility, while ice templating creates micrometer‐scale throats as “Kohn pores” enabling low‐resistance diffusion. Compared with traditional single ice‐templated hydrogels, the dual‐templated hydrogel achieves a 3.37× reduction in sorption time and 1.72× higher solar‐driven water release. Importantly, the hierarchical network mitigates dehydration‐induced capillary stresses, achieving ∼90% pore‐size retention after regeneration cycles. Consequently, the hydrogel enables excellent multi‐scenario moisture harvesting, including outdoor AWH (2.26 g g ⁻¹ day ⁻¹ ), fog collection (35 g g ⁻¹ in 250 min), and cyclic dehumidification (>80% RH to <20% RH in 150 min over 30 cycles). This work establishes a scalable hierarchical pore‐engineering strategy for fast, durable hydrogel sorbents and provides design principles for advanced moisture‐management materials.