Photocatalytic H2 production over inverse opal TiO2 catalysts

Abstract

The influence of BiVO4 and CuO on the chemico-physical properties of TiO2-based systems is reported. The performances of these systems were investigated in the photocatalytic H2 production both under UV and solar light irradiation. The characterization data pointed out that the obtained TiO2 samples have highly porous inverse opal structures with interconnected macropores. Inverse opal TiO2 exhibited higher activity in the H2 production than the commercial TiO2 due 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 TiO2 surface active sites, thus decreasing drastically the absorption of photons. The combination of the benefits of the highly ordered porous TiO2 structure and the presence of BiVO4 or small amounts of CuO can represent a promising strategy towards efficient photocatalytic H2 production.