Cobalt modified tungsten–titania nanotube composite photoanodes for photoelectrochemical solar water splitting

Cobalt modified tungsten–titania nanotubes (Co/WTNs) with different amounts of cobalt were prepared by two methods; photo-assisted deposition and one-step electrochemical anodizing method. The morphology, crystallinity, elemental composition and light absorption capability of samples were characterized by field emission scanning electron microscope, X-ray diffraction, energy dispersive X-ray spectrometer and ultraviolet–visible spectroscopy methods. All cobalt loaded samples show a red shift relative to the unloaded samples. The photo-catalytic water splitting was used as a model reaction to evaluate the photo-catalytic activity of the obtained samples. The photo-catalytic performance was examined under xenon lamp irradiation in 1 M NaOH electrolyte. All cobalt modified samples showed photo-catalytic properties better than that for the bare WTNs and bare TiO₂ samples. The total amount of H₂ evolved on the Co/WTNs2 sample was 1.9 times higher than that on the bare TiO₂ sample. The catalysts prepared in this study exhibit industrially relevant interests due to the low cost and high photocatalytic activity. These new photoanodes are highly promising photoanodes for photo-catalytic hydrogen production.