Black Diatom Colloids toward Efficient Photothermal Converters for Solar-to-Steam Generation.

Steam generation from solar power using converters has attracted significant research attention in recent years as an alternative form of energy conversion from solar energy. Rationally designed photothermal converters are essential to increase the efficiency of steam generation. Here, we propose a novel colloidal type of photothermal converter based on a frustule skeleton, which is a naturally designed colloid containing through-pore structures. Several coating processes were used to provide broadband absorption, magnetic, and water-floating properties without deteriorating pore structures, through vapor deposition polymerization of polypyrrole, weak base treatment, and additional vapor deposition polymerization of polystyrene. The prepared colloidal photothermal converter showed superior efficiency for steam generation under sunlight irradiation.