Bismuth niobate (BiNbO4) has been widely used as photoelectrocatalyst for water splitting due to its physical and chemical properties, however, it exhibits poor conductivity. Zinc oxide (ZnO) has suitable properties for photoelectrochemical applications. Nevertheless, its use is not adequate for water splitting using visible sunlight. The BiNbO4 /ZnO heterojunction formation is a way to overcome these drawbacks.
In this work, BiNbO4 nanomaterials with controlled morphology and crystalline structure were synthesized using a microwave-assisted hydrothermal methodology,1 where the pH, irradiation power and temperature were varied. ZnO films were prepared using a two-step method; first, the seed layer was spin-coated on an FTO glass, second ZnO nanorods were grown under microwave-assisted hydrothermal conditions, controlling temperature and varying time and irradiation power. The alignment of the obtained materials showed a strong correlation with the reactional conditions. To prepare the BiNbO4/ZnO heterojunction BiNbO4 suspensions were drop-casted on the ZnO films, and the resultant photoanodes show a homogeneous dispersion. Chopped light linear sweep voltammetry was obtained under dark and simulated sunlight.