SERS monitoring of the catalytic reduction of 4-nitrophenol on Ag-doped titania nanoparticles

• We prepared Ag-coated titania nanoparticles by chemical reduction of silver ions with sodium borohydride in colloidal titania.
• The Ag/titania colloidal systems were characterized by UV–vis absorption spectroscopy, TEM microscopy and Raman scattering.
• The Ag/titania nanoparticles are stable in aqueous dispersion and exhibit SERS efficiency.
• The adsorption of 4-nitrophenol on Ag-coated titania was compared with that occurring in pure Ag colloid.
• The catalytic photoreduction of adsorbed 4-nitrophenol by UV irradiation was monitored by SERS spectroscopy.

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.

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