Polyelectrolytic Cellulose Nanocrystals Enabled Efficient Atmospheric Water Harvesting

Atmospheric water harvesting (AWH) technology is a promising strategy to provide sustainable water for arid regions. Hygroscopic biomass nano/gel materials are considered ideal AWH materials because of their renewability and tunable structures. However, the insufficient hydrophilicity and slow adsorption–desorption kinetics of biomass sorbents are big challenges for realizing efficient AWH. Here, an efficient polyelectrolytic strategy of cellulose nanocrystals with poly(acrylic acid) (SCNCPA) using Ce 4+ initiated for high-performance AWH devices is demonstrated. Benefiting from the high grafting yield ∼206%, the rigid SCNCPA network coordinated with highly carboxylated surface ∼11.5 mmol g –1 have sufficient physisorption and chemisorption sites to capture water rapidly. Using an elastic fabric EF as the skeleton, assisted by small amounts of hygroscopic salt ∼20 wt %, the SCNCPA based-EF AWH device showed excellent AWH performance, the moisture sorption and desorption capacity ∼1.27 g g –1 at 30% relative humidity, and produced ∼8.4 L kg –1 of fresh water per day. This strategy provides new insights for the sustainable and valuable design of the AWH system.