Enhanced photothermal performance of copper nanoparticle–loaded graphene oxide networks for integrated solar-driven water evaporation and energy conversion

Abstract

The high real-time efficiency and multifunctional photothermal properties of pristine metal nanostructures face challenges due to stability issues, high fabrication costs, potential toxicity, and limited scalability for practical applications. Here, we design a copper nanoparticle loaded graphene oxide (GO-Cu) based floater which works as a low-cost interfacial solar evaporation platform in a synergistic manner, and also analyse their photothermal efficiency, evaporation rate, and long-term stability under simulated and daylight solar irradiation. The optimized composite materials achieved interfacial water evaporation rate of 1.6 kg m -2 h -1 with 94% energy conversion efficiency at 1 Sun irradiation. The high solar absorbing nature exhibits enhanced internal light reflections and active heat generation owing to the synergistic associations between plasmonic Cu and the porous textured GO surface of the nanocomposite, which facilitates multiple light scattering events and improved photon trapping. This engineered surface structure increases the effective optical path length, thereby enhancing solar light harvesting and thermal generation efficiency. Validation through real-time solar water evaporation reveals the superior photothermal efficiency of the floater, evidenced by rapid surface heating, sustained water temperature elevation, and a significantly enhanced evaporation rate under natural sunlight conditions. Simultaneously, It was integrated with a Bi 2 Te 3 -based commercial thermoelectric module, exhibiting excellent photothermal-to-electric conversion with a high-power output of 110 mV and power density of 0.132 mW cm -2 . This approach offers a practical floating photothermal platform with improved heat localization, suitable for real-time solar-driven water evaporation and sustainable freshwater production.