Facile Synthesis of Vertically Aligned One-Dimensional (1D) La(OH)3and La2O3Nanorods by Pulse Current Deposition

Cathodic electrodeposition of La(OH) 3 from lanthanum nitrate bath was performed for the first time. The deposition experiments were conducted at the pulse current mode with a typical on-time and off-time (t on = 5 s and t off = 10 s) and an average current density of 1 mA cm −2 (I a = 1 mA cm −2 ) for 50 min. The prepared deposit was then heat treated at 600°C for 3h in dry air atmosphere. The products were characterized by XRD, CHN, FT-IR and SEM techniques. The results revealed that the large scale and vertically aligned one-dimensional (1D) La(OH) 3 nanorods have been prepared at the applied conditions. It is also seen that heat-treatment of the prepared hydroxide nanorods resulted the La 2 O 3 nanorods without any change in their morphology. By recording the potential–time curve during the electrodeposition process, it was fund that water reduction reaction has the major role in the electrogeneration of base at the cathode surface. Based on the H 2 bubbling on the cathode surface, the mechanism of the formation and the growth of La(OH) 3 nanorods was proposed and discussed. Results of this work showed that large-scale, uniform and vertically aligned nanorods of La(OH) 3 and La 2 O 3 are achievable by pulse electrodeposition followed by heat-treatment.