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)2ratio on the product morphology were investigated, and a growth mechanism was proposed. Phase-pure Ta2O5nanorods with controlled morphology were formed in the presence of PEG and Sr(OH)2, which was necessary to form the nanorods. Sr(OH)2induced the surface dissolution and re-growth of Ta2O5. PEG induced the anisotropic growth of Ta2O5by 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 Ta2O5nanorods. A maximum apparent reaction rate constant of 0.156 min−1was obtained. The Ta2O5nanorods were stable during photocatalytic reaction and could be recycled several times without loss of activity.