Tailorable MBene aerogel with the lowest evaporation enthalpy for solar seawater desalination and wastewater purification

Growing global water scarcity has fueled the quest for sustainable and effective desalination solutions under lower energy requirements. However, it has a common strategy that has led to reducing the enthalpy of evaporation of water during solar-driven interfacial evaporation by dual-layer aerogels with effective mechanical robustness. Here, we introduce a novel class of 2D transition metal boride (MBene) integrated into the hydratable polymeric network of Polyvinyl alcohol/Chitosan/Polyurethane (MPCP) for an "all-in-one" solar evaporator. This dual-layer aerogel possesses both photothermal properties (for evaporating seawater) and reduced evaporation enthalpy (resulting in lower energy requirements). The MPCP aerogel gains broadband light absorption, and effective heat localization and exploits the polar groups on the polymer chains to interact with water molecules, resulting in reduced enthalpies of evaporation of 1132 J g(- 1) for water and 1245 J g(- 1 )for seawater, which promotes excellent solar steam generation performance with a high evaporation rate of 2.83 kg/m2h under 1 kW m(- 2) solar intensity. The MBene aerogel has favorable endurance and versatility in effectively treating a wide range of polluted wastewater sources, such as organic dyes and heavy metal solutions, with high efficiency and exceptional longevity under real seawater tests over 20 consecutive days. This work could guide the development of MBenes for efficient solar-driven water evaporation and wastewater remediation.