Energy efficient materials for solar water distillation - A review

Solar energy is one of the most powerful sources for many sustainable applications. Recently, efficient water distillation has attracted significant attention. The fresh water productivity depends on how efficiently the system harvests the incoming solar energy and converts it into useful heat. An ideal blackbody is capable of perfectly absorbing all wavelengths. The absorbed incident photons are converted into thermal energy. To approach the maximum solar absorption of a blackbody, efficient nanomaterials were developed with enhanced absorption in ultraviolet (UV)-visible to near infrared (NIR). Nanomaterials with broadband absorption, efficient heat transfer, minimum surface energy loss, and energy storage have recently emerged exhibiting accelerated the evaporation rate. These nano-enabled materials direct attention back towards traditional solar stills for future sustainable water evaporation for clean water production. Herein, novelty of the review includes (1) direct solar steam generation of highly efficient broadband materials, (2) energy exchange materials including nanoparticles & nano-fluids, (3) energy storage materials including phase change materials & nano-enabled-phase change materials and (4) other sensible energy storage materials for desalination. One result was that the local surface plasmon resonance (LSPR) effect in plasmonic metals and efficient heat trapping capabilities of carbon materials show high evaporation rates.