The effect of iron doping on the adsorption of methanol on TiO2 probed by sum frequency generation

Sum frequency generation (SFG) vibrational spectroscopy along with the molecular probe, methanol, has been used to investigate the surface chemistry of TiO2. Methanol on TiO2 has two adsorption modes: a molecular physisorption mode and a dissociative chemisorption mode. Doping TiO2 with iron leads to quenching of the dissociative adsorption. Electron paramagnetic resonance (EPR) spectra of iron-doped TiO2 particles (particle size > 100 nm) compared to the same particles leached with water show that at least some of the iron is located on the surface. Particles are also characterized with UV-visible spectroscopy.