In this work, a novel class of mesoporous ZnO/SiO2 mixed composites was prepared from different amounts of zinc oxide nanoparticles, tetraethyl orthosilicate and a structure directing agent. An interesting transition in the morphology has been observed when increasing the nanoparticles loading. Silicon nuclear magnetic resonance and infrared spectroscopy were employed to prove the presence of Zn-O-Si bonds and energy dispersive X-ray spectroscopy revealed a good dispersion of zinc in all materials. All the materials were tested for the photodegradation of Rhodamine B with good results, the best catalysts being represented by the composites containing 10 and 20 wt% nanoparticle loading. Both catalysts display a higher turnover number than unstructured ZnO nanoparticles and commercial ZnO nanopowder.