**4. Conclusions**

We have demonstrated that by purposefully adjusting the partial oxygen pressure in the sputtering chamber, reactive DC magnetron sputtering can be used to control the amount of preferential <001> orientation in TiO2 thin films. The increased orientation was shown to lead to increased photocatalytic activity, which was attributed to exposure of a larger fraction of exposed reactive {001} facets at the film surface. The films with higher orientation also responded more strongly to changes in the intensity, yielding a significantly higher (64%) UV-independent photodegradation rate constant. Moreover, the reaction order was found to be almost independent of intensity for the <101> films (Į = 0.18), while it was Į = 0.42 for the preferentially oriented <001> films, suggesting that the preferentially <001> oriented films expose more reactive sites.
