Silver Oxide-Decorated Silica Nanoparticles for Visible-Light-Driven Photolytic Pollutant Degradation and Water-Oil Separation

Abstract

Materials with hydrophobic and visible-light-driven photolytic properties find a wide range of applications, starting from self-cleaning, antifouling, antibacterial, pollutant removal, and water–oil separation. Hydrophobic properties reduce adhesion of dirt particles or bacteria, and photolytic behavior helps improve the self-cleaning property by breaking the complex pollutant molecules. Despite several advantages, not many materials are found to exhibit both these properties simultaneously. A majority of the photocatalytic activity of nanomaterials is observed in the presence of ultraviolet (UV) or strong visible-light illumination, which often destroys the hydrophobic property. We developed a simple, highly scalable, and inexpensive route of synthesizing hybrid nanomaterials by decorating ultrasmall (∼5 nm) silver oxide nanoparticles onto the surface of superhydrophobic silica nanoparticles. These highly stable hybrid nanoparticles show very strong photolytic activity in the presence of visible light of one sun intensity and are able to remove more than 99% Rhodamine B pollutant in just 5 min. Various substrates like tissue paper, plastic, glass, and sponge show superhydrophobic behavior when coated with these nanoparticles. The robust superhydrophobic nature was successfully used in self-cleaning and water–oil separation applications. The visible-light-driven strong photolysis property poses enormous potential for pollutant removal and can impart efficient germicidal property when used as a coating material.