Interfacial Growth of TiO₂-rGO Composite by Pickering Emulsion for Photocatalytic Degradation

Abstract

A 2D sandwich-like TiO₂-rGO composite was fabricated by the Pickering emulsion approach to improve the photocatalytic efficiency. Through an in situ growth of antase-TiO₂ nanoparticles on the interface of O/W type GO Pickering emulsion, TiO₂ nanoparticles were closely and densely packed on the surface of well-exfoliated rGO sheets; meanwhile, many mesoporous voids acting as the adsorption chamber and microreactor were produced. Evaluated by methylene blue (MB) degradation, its photocatalytic activity was prominent compared with the common TiO₂-based photocatalyst, with the rate constants 5 and 3.1 times higher under visible light and xenon lamp, respectively. When we applied it in the photocatalytic degradation of tetracycline hydrochloride (TCH, such as 10 ppm) under the visible light without adding any oxidants, the total removal efficiency was as high as 94% after 40 min. The mechanism of this good photocatalytic efficiency was illustrated by the scavenger trapping tests, which showed that this unique structure of TiO₂-rGO composite induced by the Pickering emulsion can significantly enhance the light absorption ability, accelerate the separation rate of electron-hole pairs, increase the adsorption capacity of organic pollutants, and hence improve the photocatalytic efficiency.