Upcycling Waste Poly(ethylene terephthalate) into a Porous Carbon Cuboid through a MOF-Derived Carbonization Strategy for Interfacial Solar-Driven Water–Thermoelectricity Cogeneration

Converting plastics into functional carbonaceous materials for solar energy conversion and storage has emerged as a prospective solution to concurrently advanced waste plastics upcycling and solar energy exploitation. However, synthesizing efficient carbon-based photothermal materials with well-defined shapes from waste plastics remains challenging. Herein, we propose metal–organic framework-derived carbonization strategy to upcycle waste poly(ethylene terephthalate) into a porous carbon cuboid (PCC) for interfacial solar-driven water–thermoelectricity cogeneration. PCC with well-controlled shapes is readily prepared from carbonization of a Ca-metal–organic framework cuboid derived from recycled poly(ethylene terephthalate). The size and porous structure of the PCC are facilely regulated by changing the carbonization temperature (700–900 °C). Owing to abundant hierarchical micro-/meso-/macropores, unique cuboid morphology, and many oxygen-containing groups of the PCC, the PCC-based solar evaporator reveals high light absorptivity, reduced evaporation enthalpy, low heat conductivity, and superior photothermal conversion capability. Thanks to these advantages, it displays an ultra-high evaporation rate (2.49 kg m–2 h–1) under 1 sun illumination, surpassing many recent evaporators. Besides, an outdoor solar-driven desalination apparatus achieves the freshwater generation amount per unit area of 7.1 kg. Significantly, the evaporator combined with a thermoelectric module generates a voltage of 201 mV at the illumination intensity of 1 kW m–2, with a maximum power density of 0.8 W m–2. This work not merely offers new opportunities for sustainable electricity and freshwater supply from renewable solar energy but also contributes to upcycling waste plastics and achieving carbon neutrality.