 The microwave-assisted sol-gel method was used to prepare ZN and CU-doped TiO2 nanoparticles with an anatase crystal structure. The powder was then thermally treated at 500 degrees Celsius before being characterized using XRD, XRF, XPS, and photocatalysis tests. The results showed that the doped TiO2 nanoparticles had higher photoactivity than the undoped ones due to the narrower band gap caused by the CU-doping. This article was authored by Luminida Pridoana, Gabriella Petcu, Sylvie Pretta, and others.