Highly efficient interfacial solar steam generation using carbonized loofah-Cu₂O composite

Abstract

Water scarcity, intensified by socioeconomic impacts and climate changes, calls for innovative and sustainable desalination methods. Solar distillation, leveraging renewable energy, represents a promising solution; however, it is hindered by low photothermal efficiency. Therefore, this study develops a novel composite material combining carbonized loofah and Cu₂O particles to enhance interfacial solar steam generation performance. The porous microstructure of loofah together with the superior photothermal properties of Cu₂O can achieve high light absorption and thermal efficiency. The CL/Cu₂O composite synthesis involved in situ copper ion adsorption followed by thermal activation, creating uniform particle distribution. XRD, SEM, and TGA analyses confirmed the presence of Cu₂O. Specifically, XRD identified ∼21 nm cubic Cu₂O crystallites, while SEM revealed a Cu₂O coating on the carbonized loofah (CL) fibers, which increased surface roughness and showed Cu₂O aggregates smaller than 250 nm. UV-Vis spectroscopy showed increased absorbance for CL and CL/Cu₂O compared to in-nature loofah (INL). The PZC was 2.0 for CL and 2.4 for CL/Cu₂O. Additionally, water absorption of the composite exceeded 400 %. Under sunlight exposure, the composite exhibited a remarkable 97 % photothermal conversion efficiency and increased solar distillation productivity by up to 150 % compared to conventional systems. The solar distillation process delivered high water purity, meeting potable water standards. The intact porous structure optimized interfacial heating, facilitating enhanced evaporation rates, even under low irradiance conditions.