The impact of surface chemistry on the performance of localized solar-driven evaporation system

Shengtao Yu,Yanming Liu,Tao Deng,Yao Zhang,Jianbo Wu,Haoze Duan,Peng Tao,Wen Shang,Xiaojun Quan,Chengyi Song

doi:10.1038/srep13600

Abstract

This report investigates the influence of surface chemistry (or wettability) on the evaporation performance of free-standing double-layered thin film on the surface of water. Such newly developed evaporation system is composed of top plasmonic light-to-heat conversion layer and bottom porous supporting layer. Under solar light illumination, the induced plasmonic heat will be localized within the film. By modulating the wettability of such evaporation system through the control of surface chemistry, the evaporation rates are differentiated between hydrophilized and hydrophobized anodic aluminum oxide membrane-based double layered thin films. Additionally, this work demonstrated that the evaporation rate mainly depends on the wettability of bottom supporting layer rather than that of top light-to-heat conversion layer. The findings in this study not only elucidate the role of surface chemistry of each layer of such double-layered evaporation system, but also provide additional design guidelines for such localized evaporation system in applications including desalination, distillation and power generation.

Highlights

Was achieved[7,9]
This work demonstrates that evaporation rate could be tuned by the chemically modified AAO-based AuNP film (AANF), which behaves like a “water gate” that controls the rate of water vapor flow
To modify the aluminum oxide (AAO)-based gold nanoparticle (AuNP) film with controlled hydrophobicity, AANF was incubated in the mixture of alkyl thiol and acetone solution with a volume ratio V(thiol):V(acetone) = 1:49 for 3 hours

Summary

Introduction

Apart from plasmonics-based light-to-heat conversion, Chen and his coworkers have recently used the light-to-heat conversion layer based on the intrinsic light absorption of graphite and reported that solar-powered water vapor can be generated efficiently by applying a double-layered structure composed of light absorbing exfoliate graphite (top light-to-heat conversion layer) and insulating carbon foam (bottom supporting layer)[5]. While both systems achieved high efficiency in evaporation[5,9], the impact of surface chemistry, or the surface wettability on the evaporation performance was not studied. With the demonstrated hydrophilic and hydrophobic behavior of AANF and the added understanding of its evaporation mechanism, this study provides new insight in designing efficient localized evaporation system and possibility to tune the evaporation performance of such systems

Methods

Results

Conclusion