A 3D porous PDMS sponge embedded with carbon nanoparticles for solar driven interfacial evaporation

Solar driven interfacial evaporation has caught the eyes of global researchers in the past few years due to its outstanding vapor generation ability by using clean solar energy. Extensive investigations have been carried out to explore solar absorber/receiver materials for efficient photothermal conversion and heat concentration at the water-air interface. However most of the presented solar absorber materials are expensive and the preparation processes are often complicated. Here we proposed a polydimethylsiloxane (PDMS) sponge with three-dimensional porous structure embedded with carbon nanoparticles (CNPs) as the solar absorber for solar driven interfacial evaporation. The proposed PDMS-CNPs sponge can be easily prepared through a simple procedure. Characterization results indicate the fabricated PDMS-CNPs sponge has microscale 3D porous structure with ideal optical absorption in visible/near-infrared (NIR) wavelength and good water transport ability after surface modification. The solar driven evaporation performance of the proposed PDMS-CNPs sponge was evaluated under different working conditions. In floating condition, the vapor evaporation rate and solar-vapor conversion efficiency at one sun radiation intensity could reach 1.36 kg/m2·h and 77.8 %, respectively. Effects of light intensity, sponge thickness, and seawater salinity were also investigated. The PDMS-CNPs sponge has exhibited excellent solar driven evaporation performance and good compatibility under different operation conditions. With its great potential in solar energy harvesting and vapor generation, it can be wide applied in researching/industrial scenarios.