Key Words:HYBRID HYDROGELS; NETWORK HYDROGEL; AEROGEL
Abstract:Hydrogels have recently emerged as promising solar evaporators due to their exceptional high evaporation rates. However, the high costs and complexity associated with the conventional freezing-thawing processes pose challenges that hinder their widespread application in large-scale solar evaporation systems. Herein, we present the successful attempt to prepare hydrogel-based solar evaporators using a salting-out/sacrificial template strategy, where salt particles serve as both salting-out agents and sacrificial templates. Without the need for freezing processes, we successfully synthesized polyvinyl alcohol (PVA) hydrogels, incorporating copper oxide and antimony-doped tin oxide particles as solar absorbers. It is demonstrated that the salting-out (Hofmeister) effect enables the cross-linking of PVA polymeric chains, imparting significant mechanical strength and dura-bility to the hydrogels. Meanwhile, the use of salt particles as sacrificial templates creates well-developed microchannels of 100-300 mu m within the hydrogels, enabling rapid water delivery. These hydrogels exhibited a solar-weighted absorptivity of 93.4 % and achieved solar evaporation rates exceeding 3.0 kg m -2h- 1 under one-sun illumination. Notably, their performance is comparable to that of state-of-the-art hydrogels prepared using freezing-thawing methods. As such, this proposed strategy holds great promise for the large-scale and cost-effective production of hydrogels as high-performance solar evaporators.
Volume:480
Issue:
Translation or Not:no