Cold energy storage technology using phase change materials (PCMs) plays an important role in cold chain logistics, air conditioning refrigeration, high temperature operation temperature control clothing and other fields. However, the performance of current phase change cold storage materials is still far from optimum. How to make its shape stable and machinability is still the key problem in its practical application. Herein, we report a novel form-stable hydrogel phase change cold storage materials (HPCCS) with water as PCM and a polyether-based 3D gel as skeleton. These hydrogels exhibited excellent shape-stability i.e. no water leakage, owing to the coaction of capillary forces and hydrogen bonding. HPCCS has similar phase change performance with ice, while HPCCS maintained cold temperature 1.85 times longer than ice. Finally, it was found that HPCCS could prolong the preservation time of Litchi which points towards its excellent potential for use in food cold chain logistics applications.

Photothermal-assisted water purification is a promising and sustainable scheme to the global clean water crisis. In this work, we report a custom-tailored bilayer photothermal aerogel to integrate multiple purification mechanisms through a cost-effective route. It is composed of a bottom layer of polyethylenimine-modified chitosan (PEI-CS) and an upper layer of CuS nanoflower/reduced graphene oxide (CuS/rGO) composites. Benefiting from the vertically aligned microchannels, PEI-CS scaffold exhibits rapid capillary pumping characteristics for water transport, and absorbs heavy metal ions by forming chelating bonds with excess hydroxyl and amino groups. With a facile spraying fabrication, the spatial distribution of CuS/rGO is rationally controlled to improve the upper thermal localization. More practically, the harnessed solar energy can be utilized by CuS/rGO nanoheterostructure with pronounced charge separation for photocatalytic degradation in parallel to efficient vapor generation. The low-cost raw materials, scalable fabrication, and multifunctionality make the bilayer aerogel be potentially applied in wastewater remediation.