Undoped CeO₂ and 0.50–5.00 mol% Fe-doped CeO₂ nanoparticles were prepared by a homogeneous precipitation combined with homogeneous/impreganation method, and applied as photocatalyst films prepared by a doctor blade technique. The superior photocatalytic performances of the Fe-doped CeO₂ films, compared with undoped CeO₂ films, was ascribed mainly to a decrease in band gap energy and an increase in specific surface area of the material. The presence of Fe³⁺ as found from XPS analysis, may act as electron acceptor and/or hole donor, facilitating longer lived charge carrier separation in Fe-doped CeO₂ films as confirmed by photoluminescence spectroscopy. The 1.50 mol% Fe-doped CeO₂ film was found to be the optimal iron doping concentration for MO degradation in this study.

Solar hydrogen generation sustained for at least several hours is demonstrated using a dye-sensitised nickel(II) oxide photocathode and BiVO₄ photoanode connected in a tandem configuration. H₂ evolution rate is 120 nmol h⁻¹ (>80% faradaic efficiency) without electrical bias or sacrificial oxidant/reductant, at pH = 7 using visible light (>420 nm).