Enhancing Solar Energy Conversion Efficiency in Interfacial Evaporation Technology using Graphite Nanoflakes/Polydimethylsiloxane Composite

Carbon-based materials such as graphite, graphene, and carbon nanotubes have been shown as a promising high-performance photothermal materials for the application in interfacial evaporation technology. In this study, we prepared a flexible graphite nanoflake (GnF)/polydimethylsiloxane (PDMS) composite with varying amounts of GnF from 1 to 10 wt%. It was found that the GnF/PDMS composite's photothermal property was optimized at 3 wt% of GnF, resulting in excellent total solar absorption of 94.8 %. As proof of concept, GnF/PDMS composite was coated on polyurethane (PU) foam to create a floatable interfacial water evaporator. Under 1 sun illumination, the coated PU with 1 wt% of GnF/PDMS composite yields an evaporate rate of 1.14 Kg/m^-2h with solar-vapor conversion efficiency of ~68 %. With the promising photothermal effect, the GnF/PDMS composite can also be used in various solar-powered applications, including desalination and purification.