Selective adsorption and photocatalytic clean-up of oil by TiO₂ thin film decorated with p-V₃D₃ modified flowerlike Ag nanoplates

Various methods are developed and used to treat oil-contaminated water, including mechanical separation, chemical treatment, biological treatment, membrane filtration, and sorption. Oil clean-up via selective sorption of the oil by an engineered surface is the most accepted technique due to its high removal efficiency and low cost. Here, a multifunctional surface providing highly selective oil sorption and clean-up capability via the photocatalytic decomposition is proposed. This novel surface is named as the “three-in-one (3-in-1) surface” since it is composed of 1) a highly photocatalytic layer, 2) micro- and nanostructures, and 3) a low surface energy layer. First, the TiO₂ photocatalytic layer is prepared by magnetron sputtering. Then flowerlike Ag nanoplates are photocatalytically deposited on the sputtered TiO₂ layer. Afterward, a low surface energy layer, poly-1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane (p-V₃D₃), is over-coated on Ag/TiO₂ surface by initiated chemical vapor deposition (iCVD) while retaining the topographical features of the surface (micro- and nanoscale surface structures). The p-V₃D₃/Ag/TiO₂ surface demonstrates a high selective adsorption to oil whereas simultaneously it shows extreme repellency to water. The p-V₃D₃/Ag/TiO₂ surface can also be photocatalytically cleaned up and this may find applications in various technology fields including water treatment, microfluidics, self-cleaning, and water harvesting.