Improved OER Catalytic Properties and Stability of Steel Anodes for Acid Water Electrolysis via Thermal Oxidation
Mr. Xiaoling Chen (PhD candidate)
Department of Mechanical Engineering
The University of Hong Kong
Date & Time
Monday, 17 April 2023
Room 7-34, Haking Wong Building, HKU
There has been a long-time desire to replace the costly noble-metal-based catalysts (IrOx, RuOx) and anode material (Ti) with cheap earth-abundant materials, like steels, for acidic water electrolysis. However, traditional stainless steels are considered unstable and non-catalytic in strong acids under high external potential. Here, we report a surface-oxidized Mn-contained stainless steel that possesses significantly improved catalytic current compared with the untreated one, which might be attributed to the mixtures of amorphous and crystalline transition-metal oxides formed on the surface. Simultaneously, the oxidized stainless steel can perform the oxygen evolution reaction (OER) in strong acid for over 20 hours. Near-surface phase transformation caused by Mn depletion might contribute to the extended stability of the surface catalytic layers during operation in acidic solutions and high external potential. This study provides a cost-effective and simple routine to make steel anodes catalytic and stable for water electrolysis in acidic media.