Polymer-derived mesoporous SiOC/ZnO nanocomposite for water decontamination was prepared by a simple mechanical incorporation of ZnO nanopowders into the commercial vinyl-functionalized polysiloxane followed by pyrolysis at 700°C for 2h. The as-prepared nanocomposite was characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, nitrogen physisorption measurement and UV–vis spectroscopy. The effects of pyrolysis temperature (700–900°C) and ZnO content (0–20wt.%) on the formation of SiOC/ZnO nanocomposite were investigated. The polymer-to-ceramic transformation of pure polymer resulted in the formation of an amorphous microporous SiOC ceramic (pore size