Super-hydrophilic LaCoO3/g-C3N4 nanocomposite coated beauty sponge for solar-driven seawater desalination with simultaneous volatile organic compound removal

Abstract

Interfacial solar steam generation (ISSG) is emerging as a promising, environment-friendly solution for fulfilling freshwater and energy demands. However, a critical challenge for ISSG lies in the presence of harmful volatile organic compounds (VOCs) in the feedwater which are co-evaporated with water, leading to more enriched concentration in condensed water. Herein, lanthanum cobaltate–graphitic carbon nitride (LaCoO₃/g-C₃N₄, LCO/g-CN) nanocomposite decorated beauty sponge (LCO/g-CN@BS) is proposed as an efficient photothermal/photocatalytic material for solar-driven seawater desalination and simultaneous VOC degradation. The hydrophobic surface of the beauty sponge after LCO/g-CN coating becomes super-hydrophilic, ensuring sufficient water supply and our LCO/g-CN@BS delivers an evaporation rate of 1.94 kg m⁻² h⁻¹ under 1 sun irradiation. This LCO/g-CN@BS shows excellent seawater desalination capacity with a self-cleaning ability when employed for saltwater purification for a salt (NaCl) concentration as high as 15 wt%. Moreover, fast photocarrier transfer between LCO and g-CN leads to enhanced photocatalytic degradation of over 90% of phenol simultaneously, which is about 60% for only an LCO-based beauty sponge. This work presents a promising approach to combining novel nanocomposites with microporous structures for efficient solar desalination, offering simultaneous VOC degradation.