Niobium ethoxide is an important precursor for depositing thin films of niobium oxide and other thin films doped with niobium. These thin films are thermally stable and show valuable magnetic, ferroelectric and good conducting properties, hence finding applications as random access memory (RAM) and photovoltaics
The electrochemical synthesis was carried out in a sealed diaphragm-free electrolyzer equipped with a condensation reflux tube.The electrolyzer was made of rigid PVC plate, with tank dimensions of 95 mm115 mm125 mm and a volume of about 1.3 L. The effective area of the niobium anode plate was 10.0 cm6.0 cm; and that of the stainless steel plate was 10.0 cm8.0 cm.1.3 L of anhydrous ethanol was fixed at a time, and the concentration of the conducting agent 0.04 mol/L, current 1.8~2.0A (current density 300~330A/m2), and pole spacing 2.5 cm. During the synthesis process, the temperature of the electrolyte rises rapidly to the boiling point of 80C, and it is difficult to control the synthesis to be carried out at a temperature lower than the boiling point of the electrolyte. Considering that the temperature increase is very effective in increasing the conductivity of the electrolyte, e.g., the conductivity of the electrolyte is 0.08104S-cm-1 at 25C for a conductive agent concentration of 0.04 mol/L; at 80C, the conductivity increases to 0.2104S-cm-1. In addition, the stirring effect formed by the boiling is advantageous in reducing the concentration polarization of the anode. Therefore, no cooling measures were used, and the electrolyte was in a boiling state throughout the synthesis process, and the produced has alcohol gas flowed back into the electrolytic tank through the condensation tube, with a synthesis time of 76~80 h. The synthesis yielded a mixed solution of niobium ethoxide and ethanol, and the excess ethanol was distilled out at 80 , and the temperature was raised to 190 , and then the decompression distillation was carried out to obtain the light-yellow, viscous liquid product niobium ethoxide.
