Nitrophenols represent common environmental pollutants because of their toxicity and resistance to microbial degradation. In the present work the SERS (surface-enhanced Raman scattering) spectroscopy has been applied to Ag/titania colloidal nanocomposites to monitor the catalytic reduction of 4-nitrophenol under UV irradiation and identify the reaction products. (C) 2013 Elsevier B.V. All rights reserved.