Solar-driven interfacial evaporation (SIE) technology
has great
advantages in seawater desalination. However, during the long-term
operation of a solar evaporator, salts can be deposited on the solar
absorbing surface, which, in turn, hinders the evaporation process.
Therefore, there is an urgent need to propose new antisalt strategies
to solve this problem. Here, we present a novel cogeneration system
leveraging a salt-tolerant, heterogeneous Janus-structured evaporator
(FHJE) for simultaneous solar desalination and thermoelectric generation.
The top evaporation layer is composed of a graphene-based photothermal
membrane pre-embedded with Fe3+ cations, which enhanced
solar absorption and energy conversion abilities. Meanwhile, the Fe3+ cations further contribute to the Donnan effect, effectively
repelling salt ions in saltwater. The bottom layer comprises a hydrogel
composed of hydrophilic phytic acid (PA) and poly(vinyl alcohol) (PVA),
fostering facilitation of water transport. The FHJE was demonstrated
to exhibit evaporation rate and efficiency as high as 3.655 kg m–2 h–1 and 94.7% in 10 wt% saltwater,
respectively, and superior salt resistance ability without salt accumulation
after 8 h of continuous evaporation (15 wt%). Furthermore, a hydropower
cogeneration evaporator device was constructed, and it possesses an
open-circuit voltage (V
OC) and a maximum
output power density of up to 143 mV and 1.33 W m–2 under 1 sun, respectively. This study is expected to provide new
ideas for comprehensive utilization of solar energy.