Solvent‐Free “ <i>Weaving</i> ” Synthesis of MOF From Waste Plastics for Record‐Efficiency Evaporation Energy Harvesting

ABSTRACT Metal–organic framework (MOF)‐based electricity generation driven by water evaporation offers a promising route toward clean energy for self‐powered systems. However, the rational fabrication of high‐performance, low‐cost MOF generators, along with a clear understanding of the intrinsic structure‐property correlations governing electricity generation, remains a significant challenge. Herein, we report an organic solvent‐free, atmospheric, two‐step “ weaving ” strategy that converts waste poly(ethylene terephthalate) (PET) into Ca‐BDC·3H 2 O via coordination‐induced in situ re‐construction‐crystallization. By leveraging the Ca(II)‐σ‐Lewis acidity and OH − nucleophilic attack mechanism, Ca(OH) 2 mediates the re‐construction of molten PET into a calcium‐coordinated intermediate (Ca‐Int), which subsequently undergoes steam‐assisted in situ re‐construction‐crystallization to form Ca‐BDC·3H 2 O. This “ weaving ” strategy achieves a total profit of $ 1.06 × 10 7 , representing a three‐order‐of‐magnitude improvement over conventional closed‐loop PET recycling methods. The resulting Ca‐BDC·3H 2 O features a uniform nanorod morphology, which synergistically enhances surface hydrophilicity and charge density, thereby facilitating ion migration and boosting electricity generation. Consequently, the Ca‐BDC·3H 2 O‐based generator (CaBDC‐G) delivers a high electrical output (19.7 V and 34.8 µA) during seawater evaporation, outperforming state‐of‐the‐art MOF‐based generators. This study establishes a paradigm for the cost‐effective functional upcycling of waste PET into MOF and provides new insights into the intrinsic structure‐performance relationships of MOF in evaporation‐driven energy harvesting.