Ultrasonic Vibration‐Driven Cold Upcycling of Waste Plastics: Enabling High‐Efficiency Seawater Distillation

ABSTRACT Plastic pollution has become a pervasive environmental crisis, intensifying greenhouse gas emissions, contaminating soils, and potentially aggravating cardiovascular risks. Prevailing recycling strategies such as incineration, landfilling, and mechanical processing remain constrained by inefficiency, contamination, and excessive energy demand, resulting in limited reusability of the recovered materials. Therefore, developing an eco‐friendly, high‐performance technology that transforms plastic waste into valuable resources is imperative. Herein, we report a novel waste plastic upcycling strategy utilizing ultrasonic vibration cold fabrication to convert waste polyethylene terephthalate into carbon materials. The polyethylene terephthalate was treated via a combination of ultrasonic vibration and dissolution methods to produce highly carbonized, porous materials with high photothermal efficiency that enable high‐performance seawater distillation. High‐frequency stress treatment promotes rapid polymer chain scission, deoxygenation, and aromatization, facilitating heat‐source‐free carbonization. We further revealed that porous carbonized materials exhibit exceptional broadband photothermal conversion with an efficiency exceeding 95%. In seawater distillation, the material generated 2.19 kg m −2 h −1 of solar steam and maintained stability in high‐salinity conditions. Leveraging the flexible fabrication capability of these porous carbons, we constructed a solar evaporation device and demonstrated a freshwater yield of 6.02 kg m −2 in 10 h of outdoor testing, which is 5.2 times that of natural evaporation.