Sepiolite supported BiVO4 nanocomposites for efficient photocatalytic degradation of organic pollutants: Insight into the interface effect towards separation of photogenerated charges.

Although the construction of clay-supported photocatalyst is a promising strategy to develop the low cost and high activity photocatalyst, only few works researched the effect of their interfaces on the photocatalytic performance. Herein, a monoclinic BiVO4/sepiolite nanocomposite was fabricated as case to study the transport mechanism of photogenerated carries based on the interfaces effect. The obtained BiVO4/sepiolite nanocomposites exhibited excellent visible light photocatalytic performance. The photocatalytic degradation rates of antibiotic tetracyclines (TCs) and methylene blue (MB) by the nanocomposites are 2 and 5.34 times higher than that by pure BiVO4 under visible light irradiation. XPS and Raman spectra confirmed the strong interfaces effect existing between BiVO4 and sepiolite clay. Moreover, PL and transient photocurrent response suggested that the strong interfaces effect effectively promoted the separation of photogenerated electron-hole pairs and further enhanced the photocatalytic performance. In addition, the results of trapping experiments revealed that the photo-induced holes (h+) were the dominant active species in the photocatalytic mechanism. This work illuminates the photocatalytic mechanism of monoclinic BiVO4/sepiolite nanocomposites and provides a novel strategy for designing the clay-supported photocatalyst for degradation of organic pollutants.