Copper‐Nanoparticle‐Decorated Hydrothermal Carbonaceous Carbon–Polydimethylsiloxane Nanocomposites: Unveiling Potential in Simultaneous Light‐Driven Interfacial Water Evaporation and Power Generation

Abstract This study introduces a hydrothermal synthesis method that uses glucose and Cu 2+ ions to create a Cu‐nanoparticle (NP)‐decorated hydrothermal carbonaceous carbon hybrid material (Cu–HTCC). Glucose serves both as a reducing agent, efficiently transforming Cu 2+ ions into elemental Cu nanostructures, and as a precursor for HTCC microstructures. An enhanced plasmon‐induced electric field resulting from Cu NPs supported on microstructure matrices, coupled with a distinctive localized π‐electronic configuration in the hybrid material, as confirmed by X‐ray photoelectron spectroscopic analysis, lead to the heightened optical absorption in the visible–near‐infrared range. Consequently, flexible nanocomposites of Cu–HTCC/PDMS and Cu–HTCC@PDMS (PDMS = polydimethylsiloxane) are designed as 2 and 3D structures, respectively, that exhibit broad‐spectrum solar absorption. These composites promise efficient photo‐assisted thermoelectric power generation and water evaporation, demonstrating commendable mechanical stability and flexibility. Notably, the Cu–HTCC@PDMS composite sponge simultaneously exhibits commendable efficiency in both water evaporation (1.47 kg m −2 h −1 ) and power generation (32.1 mV) under 1 sunlight illumination. These findings unveil new possibilities for innovative photothermal functional materials in diverse solar‐driven applications.