Efficient Solar‐Powered Interfacial Evaporation, Water Remediation, and Waste Conversion Based on a Tumbler‐Inspired, All‐Cellulose, and Monolithic Design

Abstract The 3D steam generator with cold evaporation surface (CES) provides a means for high‐efficiency interfacial steam generation due to the low heat loss and continuous ambient energy input. However, the poor floating stability of CES steam generators when suffering wave slamming has limited their practical application in open water. Herein, a cellulose‐based monolithic aerogel integrated with three structural elements is developed inspired by tumblers, which can synchronously achieve outstanding antioverturning stability in waves and a high evaporation rate (4.21 kg m⁻² h⁻¹). A single‐stage solar water purification device is constructed based on the photothermal aerogel, which attains an ultra‐high daily water yield of ≈32.6 L m⁻² and surpasses a large amount of single‐stage solar stills. The steam generator can also be used to purify wastewater containing Co²⁺ via adsorption. Gratifyingly, the Co₃O₄/C catalyst obtained from the pyrolysis of aerogels loaded with Co²⁺ exhibits good catalytic activity for carbon monoxide oxidation, demonstrating the potential for waste conversion. This work provides new insights into the design of solar steam generators used in open water, and offers a promising way for the disposal and utilization of contaminated steam generators after wastewater purification.