Na4W10O32/ZrO2 nanocomposite prepared via a sol–gel route: A novel, green and recoverable photocatalyst for reductive cleavage of azobenzenes to amines with 2-propanol

Sodium decatungstate–zirconia (Na4W10O32/ZrO2) nanocomposite was prepared through entrapment of Na4W10O32 into zirconia matrix by a sol–gel route. This new nanocomposite was characterized by means of X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FT-IR), UV–vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and surface area measurement. The nanocomposite was used as a green and recyclable heterogeneous photocatalyst for rapid and efficient reductive cleavage of azobenzenes into their corresponding amines with 2-propanol as a hydrogen donor at room temperature under N2 atmosphere. The reductive cleavage occurs without hydrogenolysis or hydrogenation of reducible moieties, such as –NO2, –OH, –CH3, –OCH3, –COOH, –COCH3, halogen and –CN. The photocatalyst has been reused several times, without observable loss of activity and selectivity. According to the azobenzene reduction, the Na4W10O32/ZrO2 nanocomposite is more effective as a photocatalyst than pure Na4W10O32, showing that the nanocomposite approach could be an excellent choice to improve the photoactivity of POMs.

Graphical abstractNa4W10O32/ZrO2 nanocomposite prepared via a sol–gel route: a novel, green and recoverable photocatalyst for reductive cleavage of azobenzenes to amines with 2-propanol, sodium decatungstate–zirconia (Na4W10O32/ZrO2) nanocomposite was prepared through entrapment of Na4W10O32 into zirconia matrix by a sol-gel route. This nanocomposite was used as a green and recyclable heterogeneous photocatalyst for rapid and efficient reductive cleavage of azobenzenes into corresponding amines with 2-propanol.Figure optionsDownload full-size imageDownload high-quality image (49 K)Download as PowerPoint slide