Assessment of the ethanol oxidation activity and durability of Pt catalysts with or without a carbon support using Electrochemical Impedance Spectroscopy

• Published in: Journal of power sources Vol. 246; pp. 392 - 401
• Main Authors: SALEH, Farhana S, EASTON, E. Bradley
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier 2014
• Subjects: Applied sciences; Carbon; Catalysis; Catalysts; Catalysts: preparations and properties; Chemistry; Direct energy conversion and energy accumulation; Durability; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrochemical impedance spectroscopy; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Ethanol; Ethyl alcohol; Exact sciences and technology; Fuel cells; General and physical chemistry; Platinum; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Polymer electrolytes; Ethanol; Polymer solid electrolyte; Alcohol; Durability; EOR; Transition metal; Catalyst layer; Carbon; Durability protocol; Supported catalyst; EIS; PEM fuel cell; Degradation; Lifetime; Platinum; Oxidation; Proton exchange membrane fuel cells; Damaging; Electrochemical impedance spectroscopy
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2013.07.109

We compared the stability and performance of 3 commercially available Johnson Matthey catalysts with various Pt loadings (20, 40 and 100%) using two different accelerated durability testing (ADT) protocols. The various Pt-loaded catalysts were tested by means of a series of intermittent life tests (1, 200, 400, 1000, 2000, 3000 and 4000 cycles). The electrochemical surface area (ECSA) loss of electrode was investigated by electrochemical technique (CV). The use of EIS as an accelerated-testing protocol distinctly elucidates the extent of degradation of Johnson Matthey catalysts with various Pt loading. Using EIS, it was possible to show that Pt-black catalyst layers suffer from increased electronic resistance over the course of ADT which is not observed when a corrosion stable carbon support is present. The effect of Pt loading was further elucidated by comparing the electrocatalytic activity of the catalyst layers towards ethanol oxidation reaction (EOR). The catalyst layer with the lowest Pt loading showed the enhanced EOR performance.