Figure 2.

Absorption spectra of 3.5 mM TiO2 nanoparticles before and after surface modification with pyrogallol (0–1.23 mM in 0.06 mM steps). Inset: Absorption at 425 nm of TiO2–pyrogallol CT complex versus pyrogallol concentration (data recorded 20 h after surface modification). Solutions of TiO2 nanoparticles used for modification were freshly prepared (A) and 4-years-old (B)

Janković et al. Nanoscale Research Letters 2009 5:81-88   doi:10.1007/s11671-009-9447-y