Disclosed herein are photocatalytic compositions comprising titanium dioxide (TiO2) nanoparticles doped with zinc having a ratio of titanium dioxide to zinc from about 5 to about 150, wherein the composition further comprises about 500 to about 1000 ppm of silicon dioxide (SiO2). Also disclosed is a method for treating or preventing microbial infestations on a surface comprising: applying a photocatalytic composition comprising titanium dioxide (TiO2) nanoparticles doped with zinc (Zn) having a ratio of titanium dioxide to zinc from about 5 to about 150, to a surface illuminated with artificial light, wherein the surface is an inanimate object.
