A solar-driven seawater desalination and electricity generation integrating system based on carbon black-decorated magnetic phase-change composites

Abstract

We have developed a novel type of solar-driven interfacial evaporation and electricity generation integrating system based on the modified carbon black (MCB)-decorated magnetic phase-change composites (MCB-MPCC) for continuous seawater desalination and clean electric power generation under intermittent solar illumination. In this system, MCB-MPCC acts as not only a solar absorber but also a hydrovoltaic functional coating. MCB-MPCC was fabricated through encapsulating n-docosane as a phase change material (PCM) in a SiO2/Fe3O4 composite shell through emulsion-templated interfacial polycondensation, followed by coating a polydopamine layer and surface-depositing MCB nanoparticles. Owing to the introduction of a PCM core, the resultant MCB-MPCC obtained a high latent heat capacity of over 145 J g−1 for consecutive seawater evaporation under intermittent solar illumination. Moreover, the surface-decorated MCB nanoparticles contribute to superior sunlight absorptivity and good wettability of MCB-MPCC, promoting a high evaporation rate of 2.67 kg m−2 h−1 for the MCB-MPCC-based evaporator under one-sun illumination along with excellent salt resistance. Meanwhile, the developed system achieved a stable output voltage of 0.43 V and output current of 10.05 μA under one-sun illumination, and the generated electric power could be stored by a commercial capacitor to provide a power supply for lightening an LED lamp.