Hierarchical Photothermal Network Spontaneously Facilitates Co‐Extraction of Clean Water and Boron
Longxin Li, Zhen Yu, Beichen Jin, Xuyu Yu, Yuqing Su, Shaoan Cheng
Abstract
Abstract Resources, energy, and food are interconnected global challenges. Herein, a double‐layer hierarchical photothermal network (HPN) is designed to co‐harvest clean water and boron. As is known, this is the first to achieve the above aims together. As a concept demonstration, the graphene oxide (GO) hydrogel with vertically aligned GO nanosheets served as the upper layer for light adsorption, while the Mg(OH) 2 /GO hydrogel acted as the bottom layer for boron extraction. HPN demonstrated a high evaporation rate of 1.87 kg m −2 h −1 , with an evaporation efficiency of 89.9% under 1 sun. Combined with the evaporation‐induced convection effect, localization concentration field, and temperature field, HPN showed a record boron extraction capacity of 789.5 mg m −2 under solar irradiation, versus just 112.16 mg m −2 under dark conditions. The contributions of these enhanced factors are 59.6%, 30.1%, and 10.3%, respectively. Ultimately, the extracted boron significantly increased the germination rate and growth of irrigated crops. In conclusion, HPN offers a novel approach to boron extraction and provides an innovative solution to advance the achievement of Sustainable Development Goals (SDGs).