A cost-effective and sustainable De-NOx photocatalyst is prepared using zinc acetate and rice husk. ZnO@SiO2 samples are obtained from the calcination of a homogenised precursor mixture at 600 degrees C. ZnO nanoparticles (70-180 nm) grow aggregated in spheres and well dispersed (40-53 m(2) g(-1) surface area) covering the silicon skeleton. The corresponding band gap for ZnO@SiO2 photocatalysts was estimated at 3.1-3.2 eV. When the samples are irradiated by sunlight in a nitrogen oxide atmosphere the NO -> HNO2 -> NO2 -> NO3- photochemical oxidation takes place. In comparison to unsupported ZnO and TiO2-P25, ZnO@SiO2 samples exhibit high NOX removal values (70%) and outstanding selectivity (> 90%), the latter related to the sensitivity of zinc oxide towards NO2 gas. This new photocatalyst is easily recyclable and reusable.