SnO2-based gas (hydrogen) anodes for aluminum electrolysis
(1. School of Metallurgy Engineering, Anhui University of Technology, Maanshan 243002, China;
2. Department of Materials Science and Engineering, Norwegian University of Science and Technology,
Trondheim 7491, Norway;
3. SINTEF Materials and Chemistry, Trondheim 7465, Norway)
2. Department of Materials Science and Engineering, Norwegian University of Science and Technology,
Trondheim 7491, Norway;
3. SINTEF Materials and Chemistry, Trondheim 7465, Norway)
Abstract: A novel SnO2-based gas anode was developed for aluminum electrolysis in molten cryolite at 850 °C to reduce energy consumption and decrease CO2 emissions. Hydrogen was introduced into the anode, participating in the anode reaction. Carbon and aluminum were used as the cathode and reference electrodes, respectively. Cyclic voltammetry was applied in the cell to investigate the electrochemical behavior of oxygen ion on platinum and SnO2-based materials. The potential for oxygen evolution on these electrode materials was determined. Then, galvanostatic electrolysis was performed on the gas anode, showing a significant depolarization effect (a decrease of ~0.8 V of the anode potential) after the introduction of hydrogen, compared with no gas introduction or the introduction of argon. The results indicate the involvement of hydrogen in the anode reaction (three-phase-boundary reaction including gas, electrolyte and electrode) and give the possibility for the utilization of reducing gas anodes for aluminum electrolysis.
Key words: SnO2-based gas anode; hydrogen anode; aluminum electrolysis