Biomass-derived carbon foam/MXene composite phase change material for high efficiency all-weather solar driven interfacial evaporation

Solar-driven interfacial evaporation (SDIE) holds great potential to mitigate global freshwater scarcity. However, its practical application is hindered by the intermittency of solar irradiation, which leads to operational instability and reduced energy utilization efficiency. To solve this issue, we proposed the incorporation of photothermal composite phase change materials (CPCMs) instead of conventional photothermal material into the SDIE system. These materials store residual heat generated during irradiation and release it under low-light or dark conditions, thereby sustaining the evaporation process and improving overall energy efficiency. In this study, a three-dimensional carbon foam (CF) derived from biomass was first synthesized and infused with MXene to enhance its photothermal properties. This modified framework was subsequently impregnated with a liquid PCM under vacuum to form the CPCMs. The resulting composites exhibited a high latent heat of 241.1 J/g and achieved a photothermal conversion efficiency of 92.2%. Finally, the CPCM-based SDIE system achieve a freshwater production rate 2.4 times higher than that of conventional systems in dark conditions, along with a 13.4% increase in total water production. Therefore, the proposed strategy effectively alleviates the operational instability caused by intermittent solar radiation, enabling efficient and stable all-weather interfacial evaporation.