Pure hexagonal Nd₂O₃ nanostructures have been synthesized via a simple precipitation way. For the first time, nanostructured Nd₂O₃ was produced with utilizing triethylenetetramine as a new precipitant and neodymium nitrate as a neodymium source. The analyses of XRD, FESEM, FT-IR, TEM, EDX, BET and DR-UV–vis were applied to characterize the as-prepared nanostructured Nd₂O₃. To evaluate the influence of various capping agents on the morphology, grain size and photocatalytic performance of Nd₂O₃, several experiments were performed. The results demonstrated that the kind of capping agent has substantial impact on the shape, grain size and photocatalytic performance of Nd₂O₃. In addition, application of the synthesized Nd₂O₃ samples as photocatalyst by photodegradation of methylene blue contaminant under ultraviolet illumination was investigated.