Enhanced Photoelectrochemical Performance of Nanocomposite Film Fabricated by Self-Assembly of Titanium Dioxide and Polyoxometalates

In order to fabricate photoelectrochemical devices, multilayer films composed of positively charged titanium dioxide (TiO 2 ) colloids and anionic tungsto(molybdo)phosphate (PW 12 and P 2 Mo 18 ) or poly(styrenesulfonate) (PSS) have been prepared by the layer-by-layer (LbL) self-assembly method. These films were characterized by UV−vis spectroscopy, IR spectra, and atomic force microscopy. Photocurrent transient measurement suggested that the photocurrent response of the PW 12 /TiO 2 composite film was highly dependent on film thickness (viz., the deposited number of layers). Both current−voltage curves and photocurrent transient measurement demonstrate that the photocurrent and power conversion efficiency of the PW 12 /TiO 2 composite film were markedly enhanced in comparison with that of the P 2 Mo 18 /TiO 2 film and the PSS/TiO 2 film. Furthermore, the PW 12 /TiO 2 composite film also exhibited the most significant photoelectrooxidation activity for methanol. These results provide valuable information for photovoltaic and photoelectrochemical applications.