Photocatalytic H2production over inverse opal TiO2catalysts

The influence of BiVO4and CuO on the chemico-physical properties of TiO2-based systems is reported. The performances of these systems were investigated in the photocatalytic H2production both under UV and solar light irradiation. The characterization data pointed out that the obtained TiO2samples have highly porous inverse opal structures with interconnected macropores. Inverse opal TiO2exhibited higher activity in the H2production than the commercial TiO2due to the peculiar porosity that allows photons to enter inside the photocatalyst. A further improvement in terms of photoactivity was verified by addition of increasing amounts of BiVO4. On the contrary a small CuO content was found to be the optimal one for the inverse opal TiO2-CuO composites. In fact, due to surface segregation effects, a higher amount of CuO can partially keep the light radiation away from the TiO2surface active sites, thus decreasing drastically the absorption of photons. The combination of the benefits of the highly ordered porous TiO2structure and the presence of BiVO4or small amounts of CuO can represent a promising strategy towards efficient photocatalytic H2production.