Synthesis of nanolayers hydroxo-(SnxOyHz) and heteropoly-(HxPWyOz) compounds of hybrid-type on silica surfaces by successive ionic layer deposition method

We determined the synthesis conditions for successive ionic layer deposition of the Sn16(OH)xPW19Oy·nH2O nanolayers on silica surfaces. The synthesized layers were characterized using UV-Vis and FTIR absorption spectroscopies, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). On heating the as-synthesized layers to 200-500 deg. C in air, incorporated water evaporate, while M-OH groups are condensed and concentration of the W-O-W and W-O-Sn bonds increase. The layers have amorphous agglomerate-like structure. The agglomerate size is from 20 to 100 nm. Upon heating to 600 deg. C, the size insignificantly increases, the agglomerate form being practically unchanged. The data obtained allow conclusion that the layers present a hybrid compound consisting of fragments of isopoly-(SnxOyHz) and heteropoly-(HxPWyOz) compounds