Toward Enhanced Atmospheric Water Harvesting in Arid Conditions via Mixed-Ligand MOF-Derived Porous Carbon

The development of solar-driven atmospheric water harvesting (AWH) is critical for synergistically alleviating water scarcity and energy demands in arid regions. However, achieving an efficient water adsorption capacity and rapid photothermal-driven desorption with adsorbents under arid climatic conditions remains a significant challenge. In this work, we design a novel nitrogen-enriched nanoporous carbon (NPCMAF-47) derived from the mixed-ligand metal-azolate framework (MAF-47). NPCMAF-47 exhibits a high water adsorption capacity, rapid adsorption kinetics, and excellent photothermal performance. Under 30% relative humidity, the material achieves a high water uptake capacity of 405 mg·g-1, along with a record-breaking water production rate of 542 mg·g-1·h-1. Notably, under diverse low-humidity arid conditions (≤40% RH), NPCMAF-47 demonstrates a superior overall water adsorption capacity compared to previously reported benchmark AWH adsorbents. Density functional theory calculations reveal a microscopic mechanism through which carbon defects and nitrogen sites synergistically enhance water adsorption by inducing a charge redistribution. This study highlights the defect-nitrogen synergy in carbon design, advancing the development of application materials for sustainable solar-driven AWH.