Development of an innovative MnO2 nanorod for efficient solar vapor generator

Finding an efficient water harvesting technique is currently highly sought-after due to the rise of water demand. Solar vapor generators (SVGs) have recently shown promising results to be used as a cleaner alternative water harvesting system for desalination application. However, recent SVGs using semiconductor as photo-thermal materials (PTMs) still suffer from a low average water evaporation performance. This study aims to develop a novel high-water generating hydrogel-based SVG consisting of cross-linked polyvinyl alcohol (PVA) matrix and designed MnO2 nanorods as solar-to-heat converter. Results indicated that the resultant hydrogel material exhibited a maximum water evaporation rate of 2.8 ​kg/(m2·h) under 1 sun. Furthermore, the PVA/MnO2 hydrogel demonstrated salt resistant and filtration capability for desalination application with a consistent evaporation rate of 2.8 ​kg/(m2·h) and >99.8% reduction of sodium ion concentration. In short, this study opens up a new pathway for the development of high performance SVG system for desalination applications.