Supramolecular Modification of Graphene Sponge with a Porphyrin Derivative Enhances the Photothermal Conversion Efficiency of a Solar Steam Generator

Solar energy seems to be a promising solution for obtaining clean water from saltwater and wastewater. With the solar steam generator system, it is possible to effectively acquire clean water from wastewater with a low-cost, sustainable, and environmentally friendly approach. In this study, PRF/GGSM, prepared by modification of gradient graphene sponge material (GGSM) with porphyrin derivative supramolecules (PRF), was investigated as a photothermal material for solar steam generation. PRF/GGSM possessing graphene and PRF served as ideal solar thermal converters that could easily gather sunlight. This material owing to its microporous and gradient hydrophilic structure has achieved a solar thermal conversion efficiency of up to 92% under 1 sun, corresponding to the water evaporation rate of 3.8 kg h-1 m-2. Moreover, this study exhibited that PRF/GGSM can efficiently generate clean water from seawater, wastewater, and even concentrated acid and alkali solutions.