writer：Ran Niu, Yang Ding, Liang Hao, Jiaxin Ren, Jiang Gong*, Jinping Qu.
keywords：solar evaporator, hydrogel
source：期刊
specific source：ACS Applied Materials & Interfaces
Issue time：2022年

The integration of renewable solar energy-driven interfacial evaporation and

photocatalysis has recently emerged as one of the most promising technologies

for simultaneous freshwater production and pollutant removal. However, the construction

of advanced integrated system with the merit of fast supply of water and

pollutant molecules remains challenging for efficient solar-driven evaporation

and photocatalytic performance. Herein, inspired by the transpiration of plant,

we fabricate a biomimetic, vertically channeled polypyrrole/foam-like carbon

nitride/poly(vinyl alcohol) hydrogel (PCH) by directional freeze-drying. We

prove that the vertically aligned channels not only reduce heat loss and

improve energy conversion efficiency, but also facilitate the

transport of water and organic pollutants to the air-water interface.

Benefiting from the advantages above, the PCH evaporator presents high solar

evaporation efficiency of 92.5%

with an evaporation rate achieving 2.27

kg m-2 h-1 under 1 kW m-2 irradiation, exceeding

many advanced interfacial solar-driven evaporators. Meanwhile, PCH

reaches the degradation efficiency of 90.6% within 1 h when dealing with tetracycline

(a typical antibiotic)-polluted water, remarkably higher than the hydrogel

without vertically aligned channels (68.6%). Furthermore, the as-formed

reactive oxygen species effectively kill Gram-positive and Gram-negative

bacterial in the source water, achieving the all-round water purification. In

outdoor experiment after 11 h sunlight irradiation, the degradation efficiency of tetracycline and freshwater production of the PCH

evaporator rises to 99.0% and 6.2 kg m-2, respectively. This work highlights

the novel biomimetic approach to fabricate multifunctional photothermal

materials for simultaneous freshwater production and polluted-water

remediation.