Molecular recognitive photocatalytic degradation of various cationic pollutants by the selective adsorption on visible light-driven SnNb2O6 nanosheet photocatalyst

Two-dimensional (2D) oxide nanosheet has attracted multidisciplinary study because of its unique physicochemical properties. In this work, a visible-light driven 2D nanosheet photocatalyst, SnNb2O6 nanosheet (SNNS), has been applied into the selective photocatalysis for the first time. It is found that the SNNS sample exhibits significantly higher selectivity and superior activity for the photocatalytic degradation of positively charged pollutants from a mixture solution compared with the bulk SnNb2O6, TiO2, and N-doped TiO2 under visible light irradiation, even when the concentrations of other pollutants are much higher than those of cationic pollutants. This high selectivity and activity may be explained by the integrative effect of the unique crystal structure, highly selective adsorption performance, and oxidation of the photogenerated holes. By analyzing the results of X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectroscopy, as well as combining with the crystal structure of the nanosheet, the interaction between the SNNS sample and the pollutants has also been well investigated. In addition, the photocatalytic mechanism under visible light irradiation has also been discussed. Our current work may widen the application of the nanosheet and open promising prospects for the utilization of the nanosheet as visible light photocatalyst for selective degradation in environmental remediation.

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► SnNb2O6 nanosheet was applied into selective photocatalysis for the first time.
► Nanosheet exhibits very high selectivity and activity in mixture pollutants.
► Relationship between adsorption and photocatalytic activity was investigated.
► Roles of active species on the selective photocatalysis were discussed.
► Adsorption modes of cationic pollutants over nanosheet have also been proposed.