<div>DOI: 10.1002/ ((please add manuscript number))</div><div><b>Article type:</b> Research Article</div><div>Polyoxometalates-Modulated Hydrophilic-Hydrophobic Composite Interfacial
Material for Efficient Solar Water Evaporation and Salt Harvesting in
High Salinity Brine</div><div>Sihang Cheng, Cuimei Liu, Yingqi Li, Huaqiao Tan*,Yonghui Wang,
Yangguang Li*</div><div>S. H. Cheng, C. M. Liu, Prof. Y. Q. Li, Prof. H. Q. Tan, Prof. Y. H.
Wang and Prof. Y. G. Li</div><div>Key Laboratory of Polyoxometalate and Reticular Material Chemistry of
Ministry of Education, Faculty of Chemistry, Northeast Normal
University, Changchun, 130024, P. R. China</div><div>E-mail: tanhq870@nenu.edu.cn; liyg658@nenu.edu.cn</div><div><b>Abstract</b> </div><div>Solar vapour generation (SVG) represents a promising technique for
seawater desalination to alleviate the global water crisis and energy
shortage. One of its main bottleneck problems is that the evaporation
efficiency and stability are limited by salt crystallization under
high-salinity brines. Herein, we demonstrate that the 3D porous
melamine-foam (MF) wrapped by a type of self-assembling composite
materials based on reduced polyoxometalates (i.e. heteropoly blue, HPB),
oleic acid (OA) and polypyrrole (PPy) (labeled with
MF@HPB-PPy<sub>n</sub>-OA) can serve as efficient and stable SVG
material at high-salinity. Structural characterizations of
MF@HPB-PPy<sub>n</sub>-OA indicate that both hydrophilic region of
HPBs and hydrophobic region of OA co-exist on the surface of composite
materials, optimizing the hydrophilic and hydrophobic interfaces of the
SVG materials, and fully exerting its functionality for ultrahigh
water-evaporation and anti-salt fouling. The optimal
MF@HPB-PPy<sub>10</sub>-OA operates continuously and stably for
over 100 h in 10 wt% brine. Furthermore,
MF@HPB-PPy<sub>10</sub>-OA accomplishes complete salt-water
separation of 10 wt% brine with 3.3 kg m<sup>-2</sup>h<sup>-1</sup> under 1-sun irradiation, yielding salt harvesting
efficiency of 96.5%, which belongs to the record-high of high-salinity
systems reported so far and reaches zero liquid discharge. Moreover, the
low-cost of MF@HPB-PPy<sub>10</sub>-OA (2.56
$/m<sup>2</sup>) suggests its potential application in the
practical SVG technique.</div><div>Keywords: polyoxometalates (POM), heteropoly blue (HPB),
hydrophilic-hydrophobic interface, solar vapour generation (SVG),
salt-water separation</div>