Superhydrophobic and Photocatalytic Synergistic Self-Cleaning Coating Constructed by Hierarchically Structured Flower-like Hollow SiO₂@TiO₂ Spheres with Oxygen Vacancies

Abstract

The self-cleaning coating has both superhydrophobic physical and photocatalytic chemical self-cleaning properties, which has attracted the wide attention of researchers in recent years. First, the flower-like hollow SiO 2 @TiO 2 spheres with oxygen vacancies (rFHSTs) were prepared by the liquid-phase reduction method, in which several different functional components were integrated. Meanwhile, the influence mechanisms of the physical structure and chemical composition on the photocatalytic properties are discussed in detail. The results proved that rFHSTs exhibited the enhanced photoresponse range and photocatalytic degradation performance in visible light because of the synergistic effect of the microstructure (internal cavity, 3D flower-like nanosheet), SiO 2 /TiO 2 heterojunction structure, and oxygen vacancies. After that, superhydrophobic modified rFHSTs were used as fillers to fabricate PVA/PFDTS-rFHSTs composite coatings with both physical and chemical selfcleaning properties. The self-cleaning performances and principles of the composite coating were examined and explored. The results showed that the low surface energy of the hydrophobic chain segment, the inherent particle effect, and the photocatalytic activity of rFHSTs were responsible for the superhydrophobic and photocatalytic effects, finally endowing the composite coating with selfcleaning performance. In short, this study is profound for the development and application of self-cleaning coatings with both physical and chemical performances.

Fluorine-Free Superhydrophobic Petal-like SiO2 Nanostructure Supported on Cotton for Oil–Water Separation

“…Superhydrophobic surfaces have gained significant attention for low wettability, characterized by a static water contact angle (WCA) greater than 150° and a sliding angle (SA) less than 10°. These surfaces find applications in various fields, including self-cleaning, − water-repellent properties, , oil–water separation, − antibacterials, anti-icing, , and antifogging. , To construct a superhydrophobic surface, two factors are critical: a low surface energy and a micronano rough structure. In recent studies, various strategies such as dip-dry coating, − spray coating, layer-by-layer self-assembly, templating, , chemical vapor deposition, and sol–gel process − have been used to establish a superhydrophobic surface.…”