Sputter-deposited Ti oxide films used for photoelectrocatalytic degradation of 4-chlorophenol

Ti oxide films were made by reactive magnetron sputtering under conditions yielding "penniform" structures with large porosity. X-ray diffractometry s howed that rutile-like and anatase-like films were produced depending on th e oxygen content in the sputter plasma. Rutherford backscattering spectrome try documented some oxygen overstoichiometry. Spectral optical measurements were used to analyze the absorption around the fundamental band gap and to give evidence of some hydration and hydroxylation in the films. The variou s Ti oxide films were brought in contact with 4-chlorophenol (4-CP), whose photo-electrocatalytically induced degradation under ultraviolet irradiatio n was investigated in a reactor allowing optical probing of 4-CP as well as of intermediate reaction products such as benzoquinone. A rutile-like stru cture was conducive to the degradation of 4-CP, which can be reconciled wit h the band gap being suitable for producing photoinduced holes capable to e ffecting oxidation of the pollutant. (C) 2001 Kluwer Academic Publishers.