Electrocatalytic Conversion of Carbon Dioxide and Nitrate Ions to Urea by a Titania-Nafion Composite Electrode

CO₂ and nitrate ions were successfully converted to urea by a TiO₂ -Nafion nanocomposite electrode under ambient conditions. The composite electrode was constructed by dropcasting the mixture of P25 titania and Nafion solution on an indium-doped tin oxide (ITO) electrode. When the electrode was electrolyzed in CO₂ -saturated 0.1 m KNO₃ (pH 4.5) solution at -0.98 V versus Ag/AgCl, urea was formed with a Faradaic efficiency of 40 %. The other reduced products obtained were NH₃ , CO, and H₂ .