The synthesis of Bi2WO6 inverse opal photonic crystals is performed via a facile and economical method. Bi2WO6 inverse opals exhibit much higher photocatalytic activities for the degradation of methylene blue and salicylicic acid under visible light illumination as compared with a reference nanofilm. The photon‐to‐hydrogen conversion efficiencies of photoelectrochemical water splitting exhibit an almost threefold increase due to the inverse‐opal structure.

The results of Mott-Schottky measurements on thin film TiO 2 electrodes have been compared with the photocatalytic activities of these films for the photocatalytic reduction of methylviologen and the oxidation of methylene blue, respectively, under UV light irradiation. The purpose of this study was to find an alternative method to predict the photocatalytic activity of titanium dioxide thin films. While impedance measurements were carried out on FTO-glass, the activity tests were performed separately on standard glass substrates. The initial photonic efficiency of the reduction of methylviologen was found to correlate with both the flatband potential and the donor density of the investigated titanium dioxide thin film electrodes. The more negative the flatband potential the higher are both the donor density and the photonic efficiency of the photocatalytic methylviologen reduction. No such dependency was found, however, for the photonic efficiency of the methylene blue oxidation.

We report photocatalytic studies employing colloids of pure hematite (α-Fe2O3) and hematite loaded with 1 and 5 wt % platinum, respectively. The kinetics of the dechlorination of the redox indicator 2,6-dichloroindophenol (DCIP) have been studied in aqueous colloidal suspensions of hematite at pH 7. At the same time, α-Fe2O3 carries out the photooxidation of water. The formation of hydroxyl radicals and of H2O2 has been investigated employing coumarin and p-hydroxyphenylacetic acid as reagents, respectively. With an increased amount of platinum on the colloidal surface, an enhanced photonic efficiency of the dye reduction is observed.

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