Solar-Driven Interfacial Water Evaporation Using Open-Porous PDMS Embedded with Carbon Nanoparticles

Abstract

Solar-driven evaporation is a promising technology with many potential applications including desalination, power generation, purification, sterilization, and phase separation. Recently, much research has been directed toward increasing solar-driven evaporation efficiencies with photothermal materials that reside at the air–water interface to provide a localized thermal energy source when subjected to solar radiation. In this work, composite foams of carbon nanoparticles (CNPs) and polydimethylsiloxane (PDMS) were fabricated by a facile salt-leaching technique and used as interfacial receivers for solar evaporation. The inclusion of CNPs significantly increases the solar absorptivity of the foams to ∼97% without impacting their inherently low thermal conductivity. Polyvinyl alcohol (PVA) modification was applied to endow the foams with hydrophilicity, thereby enabling continuous water transport to the air–water interface. An enhanced water evaporation rate of 1.26 kg/m2·h with a solar-to-evaporation efficiency of 80% was achieved under a relatively low solar input of 850 W/m2. With their simple structure and excellent photothermal performance, the PVA-CNP/PDMS foams are promising candidates for solar evaporation applications.