Green water-based fabrication of SiO₂–TiO₂ aerogels with superhydrophobic and photocatalytic properties and their application on cotton fabric

Abstract

In this work, a green, simple, low-cost, and highly effective sol–gel method was used to successfully fabricate water-based SiO₂–TiO₂ aerogels with the help of surfactant by the incorporation of TiO₂ into methyltrimethoxysilane-based SiO₂ sol. The surface morphologies, chemical composition, physical properties, wettability and photocatalytic activity of SiO₂–TiO₂ aerogels were characterized by Fourier transformed infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), water contact angle and ultraviolet–visible absorption spectrum measurements. When the molar ratio of Si to Ti was 10:1, the SiO₂–TiO₂ aerogel samples showed not only low bulk density (0.122 g cm⁻³) and high porosity (96.11%), but also the high-efficient photodegradation ratio of 98.30% under UV light for 150 min. The obtained SiO₂–TiO₂ aerogels were photocatalytically active and superhydrophobic with the water contact angle (WCA) of 152°, showing the promising potential wide application. Moreover, the superhydrophobic and photocatalytic properties of the SiO₂–TiO₂ aerogels coated cotton fabric were also investigated. The coated cotton fabric not merely possessed antifouling, liquid-repellent and self-cleaning capabilities due to its superhydrophobic property, but also performed the considerable photocatalytic activity by the decomposition of methylene blue (MB) and Rhodamine B (RhB) under ultraviolet (UV) exposure.