One-step fabrication of all-in-one biocompatible polymer wrapping carbon dots for efficient atmospheric water harvesting from plants

Plant transpiration is a ubiquitous process that continuously release water vapor to the atmosphere, which is an untapped resource of water. Hygroscopic sorbents are potential candidates to address water scarcity through efficient solar-driven atmospheric water harvesting (AWH). However, the composite sorbents containing multiple components are typically toxic and environment harmful, with low photothermal efficiency and poor cyclic stability. Herein, we utilize all natural plant-derived precursors for one-step synthesis of phosphate-polymer-wrapped carbon dots (PWCD) with multi-carbonized cores inside and wrapped polymer chains in the surrounding. Without need to combine other materials, the single all-in-one PWCD particle exhibits multiple functions including low toxicity, biocompatible, high moisture absorption, low-energy desorption, high photothermal temperature, excellent cyclic stability and antibacterial properties. The PWCD can absorb water vapor across a wide range from 10% to 90% RH, with water uptake ranging from 0.11 to 3.23 g water /g absorbents . Furthermore, PWCD also shows excellent photothermal desorption ability, with final photothermal temperature surpass 100 °C for in situ sterilization. The presence of wrapped polymer prevents PWCD from aggregation and agglomeration, enhancing their cyclic stability. As the results, the biocompatible PWCD was successfully applied for water harvest from plant transpiration, producing 0.51 g·g −1 per cycle near Epipremnum aureum while keeping plant fresh.