In this work we investigated the tartrazine photodegradation by modified and unmodified silicon nanowires (SiNWs). SiNWs were elaborated by one-step metal-assisted electroless chemical etching of silicon substrate in HF/AgNO3 aqueous solution. The modification of SiNWs was carried out by nanoparticles of platinum, palladium, silver, gold and copper in chemical solutions of PtO2, PdCl2, AgNO3, AuCl3 and CuSO4, respectively. The results show that Cu-modified silicon nanowires give the highest photocatalytic activity compared to the unmodified SiNWs and SiNWs modified with nanoparticles of Au, Pt, Pd and Ag. (C) 2016 Elsevier Ltd. All rights reserved.