Preparation, Characterisation, and Photocatalytic Behaviour of Co-TiO2 with Visible Light Response

Abstract EN

The preparation of cobalt-modified TiO2 (Co-TiO2) was carried out by the incipient impregnation method starting from commercial TiO2 (Degussa, P-25) and cobalt acetate.

XPS data show that cobalt is incorporated as divalent ion, and it is likely present within few subsurface layers.

No appreciable change in structural-morphologic properties, such as surface area and anatase/rutile phase ratio, was observed.

Conversely, Co addition brings about conspicuous changes in the point of zero charge and in surface polarity.

Diffuse reflectance spectra feature a red shift in light absorption that is dependent on the amount of cobalt.

The influence of cobalt addition on the performance of TiO2 as a photocatalyst in the degradation of 4-chlorophenol and Bisphenol A is investigated.

The results show that the modified oxide presents a higher photoactivity both for illumination with UV-visible (λ>360 nm) and visible light (λ>420 nm; λ>450 nm), and that this enhancement depends on the amount of the added species and on the final thermal treatment in the preparation step.

We also show that Co-TiO2 is a more active catalyst than pure TiO2 for the reduction of O2 in the dark, which is an important reaction in the overall photocatalytic processes.