Photothermal Halloysite Aerogel Encapsulating Phase Change Materials for Solar-Driven Seawater Desalination

Abstract

The inherent limitations of phase change materials (PCMs), namely liquidphase leakage and insufficient intrinsic light absorption, pose significant challenges to their scalable application in photothermal conversion and storage systems. This study employs polydopamine (PDA) pre-coated halloysite nanotubes (HNTs) as fundamental building blocks to construct a three-dimensional porous aerogel (PHG), which is subsequently utilized to encapsulate polyethylene glycol (PEG). A synergistic effect between the HNTs aerogel and the PDA coating leads to a collaborative enhancement of the composite PCMs (PEG/PHG). The porous structure of PHG guarantees a high encapsulation efficiency of 93.1% and a latent heat of 166.7 J g -1 , whereas the PDA coating boosts the photothermal conversion efficiency to 92.88%. The exceptional thermal management and highly efficient photothermal conversion capabilities of PEG/PHG are key enablers for its deployment in solar-driven seawater desalination.The PEG/PHG-integrated evaporator combines the dual advantages of high-efficiency solar-driven operation and sustained performance during intermittent periods. It achieves a high evaporation rate of 3.03 kg m -2 h -1 under one sun irradiation, while also maintaining a continuous evaporation performance of 1.67 kg m -2 h -1 even in the absence of light. Therefore, this research successfully integrates photothermal composite PCMs with solar-driven seawater desalination, paving the way for their application and offering new avenues for future development.