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

• The durability of JM catalysts with different wt% Pt were studied using EIS.
• The ethanol oxidation activity of these catalysts was also evaluated.
• JM20 catalyst had highest durability and ethanol oxidation performance.
• JM20 and JM40 showed no carbon corrosion after potential cycling, just Pt growth.
• EIS showed JM100 (Pt-black) had increased Relectronic after potential cycling.

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.

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