Photocatalytic degradation of methylene blue (MB) in water was examined using Er3+-doped TiO2 (Er -TiO2) nanorods prepared by a sol-gel derived electrospinning, calcination, and subsequent mechanical grinding. Different concentrations of Er dopant in the range of 0-1.0 mol% were synthesized to evaluate the effect of Er content on the photocatalytic activity of TiO2. Among Er3+-TiO2 catalysts, the 0.7 mol% Er3+-TiO2 catalyst showed the highest MB degradation rate. The degradation kinetic constant (k) increased from 1.0 x 10(-3) min(-1) to 5.1 x 10(-3) min(-1) with the increase of Er3+ doping from 0 to 0.7 mol%, but decreased down to 2.1 x 10(-3) min(-1) when Er3+ content was 1.0 mol%. It can be concluded that the degradation of MB under UV radiation was more efficient with Er3+-TiO2 catalyst than with pure TiO2. The higher activity might be attributed to the transition of 4f electrons of Er3+ and red shifts of the optical absorption edge of TiO2 by erbium ion doping. (c) 2012 Elsevier B. V. All rights reserved.