Synergistic Energy Nanoconfinement and Water Activation in Hydrogels for Efficient Solar Water Desalination.

Abstract

Precisely controlled distribution of energy in solar-to-thermal energy conversion systems could allow for enhanced energy utilization. Light absorbing hydrogels provide a means for evaporating water by using solar energy, yet targeted delivery of solar thermal energy to power the water evaporation process remains challenging. Here we report a light-absorbing sponge-like hydrogel (LASH) that is created by in-situ gelation of a light absorbing nanoparticle-modified polymer leading to synergistic energy nanoconfinement and water activation. By means of experimental demonstration and theoretical simulation, the LASH presents record high vapor generation rates up to ~3.6 kg m⁻² h⁻¹ and stable long-term performance under one sun (1 kW m⁻²) irradiation. We investigate the energy confinement at the polymer-nanoparticle interphases and the water activation enabled by polymer-water interaction to reveal the significance of such effects for high-rate solar vapor generation. The water vaporization enabled by LASHs can remove over 99.9% of salt ions in seawater through solar water desalination. The fundamental design principle, scalable fabrication route and superior performance offer possibilities for portable solar water purification, industrial solar-powered water treatment and other advanced solar thermal applications.

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Identifiers

DOI

10.1021/acsnano.9b02301

Journal

ACS Nano

Year

2019