Polymer microsphere-confined in-situ growth of MOF-303@poly(acrylate) composites for rapid atmospheric water harvesting under arid conditions

Abstract Metal-organic frameworks (MOFs) have emerged as exceptional materials for atmospheric water harvesting (AWH) due to their superior adsorption properties in low humidity conditions (≤ 20% RH), but most MOF adsorbents typically exist in powder form, thus their aggregation induces significant transfer resistance to limit their adsorption kinetics and practical application potential. Here we prepared an organic-inorganic MOF-303@poly(acrylates) composite by in-situ growing MOF-303 within porous poly(acrylates) spheres. Our results demonstrate that the 87% loading of MOF-303@poly(acrylates) exhibits uniformly dispersed crystals with a crystal size that is 40% smaller compared to pure MOF-303 powder, while maintaining a water vapor adsorption capacity of 0.348 g·g−1 at 20% RH and 298 K, which is comparable to that of an equivalent mass of the pure MOF-303 powder. In the dynamic water vapor test with a constant flow rate (50 mL·min−1), the adsorption and desorption rates of the composite are 2.74 and 2 times faster than those of MOF-303 powder. After 100 consecutive adsorption and desorption cycles at 1780 mL·min−1 (0.95 m·s−1, light air), the water vapor adsorption capacity showed no significant decline. This composite strategy not only enhances adsorption kinetics but also advances MOF-based AWH systems for engineering applications.