Titanium dioxide has promising photocatalytic properties that can be used in the treatment and purification of air and water. In this paper, the influence of spray parameters and additives (iron(II, III) oxide, aluminum oxide, and yttrium oxide) to generate anastasis on the microstructure and surface properties of titanium dioxide layers is investigated. The photocatalytic effect of the layers and their dependence on the layer structure is investigated with the help of the degradation of acetaldehyde. The results show that the layers consist of both anastase and rutile. The proportion of anastasis in the layers is estimated at 3-15%, which is determined by the degree of melting in the process. It has been proven that titanium dioxide layers are suitable for decomposing acetaldehyde under ultraviolet radiation, the performance increasing with increasing anastasis. Paper includes a German-language abstract.