Hydrothermal synthesis and photocatalytic properties of tantalum pentoxide nanorods

Tantalum pentoxide (Ta2O5) nanorods were hydrothermally synthesized using polyethylene glycol (PEG) as a guiding agent. The nanorods were characterized by X-ray diffraction, scanning and transmission electron microscopies, and diffuse reflectance ultraviolet-visible and photoluminescence spectroscopies. The effects of crystallization duration and Ta2O5/Sr(OH)(2) ratio on the product morphology were investigated, and a growth mechanism was proposed. Phase-pure Ta2O5 nanorods with controlled morphology were formed in the presence of PEG and Sr(OH)(2), which was necessary to form the nanorods. Sr(OH)(2) induced the surface dissolution and re-growth of Ta2O5. PEG induced the anisotropic growth of Ta2O5 by acting as a capping agent. The products were used to photocatalytically degrade rhodamine B under ultraviolet irradiation. The catalytic activity directly correlated with the length-diameter ratio of the Ta2O5 nanorods. A maximum apparent reaction rate constant of 0.156 min(-1) was obtained. The Ta2O5 nanorods were stable during photocatalytic reaction and could be recycled several times without loss of activity. (C) 2015, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.