Affiliation: | a Department of Molecular Science and Technology, Faculty of Engineering, Doshisha University, Miyako-dani 1-3, Tadara, Kyotanabe, Kyoto 610-0321, Japan b Research and Development Department, Shimonoseki Mitsui Chemicals Co. Ltd, Sakomachi 7-1-1, Hikoshima, Shimonoseki, Yamaguchi 750-0092, Japan c Ohnohara Research and Development Center, Toyo Tanso Co. Ltd, Nakahime 2181-2, Ohnohara-cho, Mitoyo-gun, Kagawa 769-1612, Japan |
Abstract: | A nickel sheet coated with LiNiO2 powder having average particle sizes of 40 and 50 μm in diameter by atmospheric plasma spraying technique was employed as the anode for electrolytic production of NF3. In electrolysis of a molten NH4F·2HF at 100 °C and 25 mA cm?2, the anode gas generated at the LiNiO2 coated Ni sheet anode was composed of N2, O2, NF3, N2F2, N2F4, and N2O, and its composition was almost the same as that at the Ni sheet anode. The current efficiency for the NF3 formation on the LiNiO2 coated Ni sheet anode was increased to reach the constant value of ca. 55% during electrolysis for 100 h, and it was almost the same as that on the Ni sheet anode. The anode consumption of the LiNiO2 coated Ni sheet was small compared with that of the Ni sheet. Also, the oxygen content in the oxidized layer formed on the LiNiO2 coated Ni sheet anode was high compared with that on the Ni sheet anode, and the surface of the LiNiO2 coated Ni sheet anode was covered with a compact and adhesive film having some defects. Although the bottom of the hollow was covered with a thinner layer, no pore penetrated through the oxidized layer. Hence, the LiNiO2 coated Ni sheet anode is favorable for the electrolytic production of NF3, and the oxidized layer on the LiNiO2 coated Ni sheet anode has the higher resistance to corrosion, because of the compact and adhesive film containing the higher content of oxygen formed on the anode. |