Synergistic High‐Rate Solar Steaming and Mercury Removal with MoS 2 /C @ Polyurethane Composite Sponges

Abstract Solar steam generation, a sustainable water‐purification technology, holds substantial promise in resolving the global issue of shortage of drinkable water. Here, the design, fabrication, and high‐performance of an innovative 3D solar steamer, offering synergistic high‐efficiency steaming and heavy metal removal functions are reported. The device is made of synthesized carbon‐molybdenum‐disulfide microbeads electrostatically assembled on a 3D polyurethane sponge. The mesoporous composite sponge also serves as a freestanding water reservoir that avoids one‐side contact to bulk water, effectively suppressing the commonly observed parasitic heat loss, and offering a high energy efficiency of 88%. When being sculpted into a 3D spoke‐like structure, the composite sponge achieves one of the highest evaporation rates of 1.95 kg m −2 h −1 at 1 sun. The solar steamer is demonstrated for water treatment, i.e., decontamination of metal ions, disinfection, and reducing alkalinity and hardness of river water. Particularly, the strong mercury adsorption of MoS 2 reduces mercury levels from 200 to 1 ppb, meeting the stringent standard set by the Environmental Protection Agency, which is the first demonstration of mercury‐removal powered by solar energy. The unique design, fabrication, water‐handling strategy, and mercury‐removal function of this high‐performance solar steamer can inspire new paradigms of water treatment technologies.