A photodegradable plastic is described, comprising cellulose esters and also, if appropriate, additives. A particular characterizing feature of this photodegradable plastic is that it comprises a dispersed photocatalytic carbon-modified titanium dioxide. Comparative experiments show that this photodegradable plastic exhibits a surprisingly high increase in photocatalytic degradability when compared with products in which a conventional or other modified titanium dioxide is used. This improvement is apparent in particular in use of the photodegradable plastic according to the invention when it is further processed to give moldings. The photodegradable plastic can, for example, first be further processed to give a filter tow. This can be used to produce filter rods, and these can then be used to produce filter plugs for filter-tip cigarettes.