Enhanced interfacial solar driven water evaporation performance of Ti mesh through growing TiO2 nanotube and applying voltage

Abstract

Interfacial solar driven water evaporation (ISDWE) technology has been widely studied to desalinate seawater in aiming to alleviate the scarcity of clean water. In this paper, the ISDWE performance of Ti mesh was enhanced by anodized TiO2 nanotube film and applied voltage, and the water evaporation rate increased from 1.20 kg•m−2•h−1 to 2.48 kg•m−2•h−1. Due to hydrophilic and nanoporous nature of TiO2 nanotube film, the solar absorptivity, wettability of Ti mesh was improved, the water evaporation enthalpy was reduced, and the water evaporation rate reached 1.98 kg•m−2•h−1. For the superior ISDWE performance with applied voltage, electrothermal effect and internal electrical filed were proved to be contributing factors. The solar irradiation can enhance the electrothermal effect for the semiconducting nature of TiO2. The internal electrical field can optimize the solar absorptivity and water evaporation enthalpy through doping TiO2 and breaking water clusters. Moreover, the applied voltage also increased the salt-resistance property of Ti mesh coated with TiO2 nanotube film. When increasing NaCl concentration, stable water evaporation rate was attainable under 1.2 V, whereas continuous deceleration of water evaporation occurred without external voltage. Therefore, our study provides strategies for achieving high efficient and salt-free seawater desalination by ISDWE technology.