Adsorption study of 4‐MBA on TiO2 nanoparticles by surface‐enhanced Raman spectroscopy

Abstract In this paper, the adsorption of 4‐mercaptobenzoic acid (4‐MBA) on TiO 2 nanoparticles was studied mostly by surface‐enhanced Raman spectroscopy (SERS) and UV‐vis spectroscopy, at different pH values as well as under different temperatures and concentrations. The results show that the 4‐MBA molecules are bonded to the TiO 2 surface both through the sulfur atoms and COO − groups at neutral or alkaline pH, but only through the sulfur atom at acidic pH. Furthermore, the 4‐MBA molecules possess high adsorptive stability on TiO 2 at a comparatively high temperature (150 °C). Concentration‐dependent SERS experiments show that the saturation concentration for 4‐MBA adsorbed on TiO 2 is about 10 −3 M in natural case (pH = 6). Copyright © 2009 John Wiley & Sons, Ltd.