Nd-modified BaSn oxide nanorods and their photocatalytic activity toward gentian violet

Neodymium (Nd)-modified barium tin (BaSn) oxide composite nanorods (NdBSCNRs) with different neodymium contents were synthesized by using an in situ photodeposition process. The composite nanorods were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, solid diffuse reflectance spectroscopy, electrochemical impedance spectroscopy and photoluminescence spectroscopy. The composite nanorods consist of monoclinic barium hexahydroxy stannate (BaSn(OH)₆), orthorhombic tin (IV) oxide (SnO₂), monoclinic barium hydroxide (Ba(OH)₂), cubic neodymium (III) oxide (Nd₂O₃) and hexagonal neodymium phases. The composite nanorods, with diameters of 50–150 nm and a polycrystalline structure, are covered with nanoparticles with a size of about 50 nm. Compared with the band gap of barium tin oxide composite nanorods (BSCNRs), that of the NdBSCNRs decreases to 3.34 eV, increasing the light absorption ability. The NdBSCNRs exhibit enhanced photocatalytic performance toward gentian violet (GV) under ultraviolet light illumination owing to neodymium modification. The photocatalytic activity of the NdBSCNRs is closely related to the dosage of composite nanorods and neodymium content. The reaction rate constant k value of the NdBSCNRs for GV degradation increases obviously, with the highest k value (0.037 min⁻¹) being 7.4 times that (0.005 min⁻¹) of the BSCNRs. Superoxide ion radicals, hydroxyl radicals and holes are the main reactive species, and NdBSCNRs are stable and recoverable for GV degradation.