Tailoring Nanoscale Surface Topography of Hydrogel for Efficient Solar Vapor Generation

TLDR

Solar vapor generation can separate soluble or dispersing contaminants from water and is attractive for green energy–based water purification. The study proposes enhancing solar vapor generation by tailoring the surface topography of a hydrogel‑based solar evaporator. The authors constructed an easy‑to‑install solar still using cost‑effective poly(vinyl alcohol) and activated carbon to demonstrate domestic or emergency purification potential. The nanotextured evaporator achieved a water evaporation rate of ~2.6 kg m⁻² h⁻¹ at ~91 % energy efficiency under one sun, illustrating that the design principles enable scalable, processable solar evaporators from accessible materials.

Abstract

Solar vapor generation, which can separate the soluble or dispersing contaminants from water, is particularly desirable owing to its green energy utilization for water purification technology. Here, we present a concept of enhancing solar vapor generation by tailoring surface topography of the hydrogel-based solar evaporator. Via nanotexture-enhanced heat flux at the evaporation front, the obtained solar evaporator achieves a water evaporation rate of ∼2.6 kg m–2 h–1 at ∼91% energy efficiency under one sun (1 kW m–2). An easy-to-install solar still based on this solar evaporator consisting of cost-effective poly(vinyl alcohol) and activated carbon is deployed to demonstrate the potential for domestic or urgent water purification purposes. Such new design principles of hydrogel-based solar evaporators provides a useful means for surface-enhanced water evaporation to inspire scalable and processable solar evaporators from accessible raw materials.