Effect of Hydrogen Sulphide Contamination on Platinum Catalyst Degradation in Polymer Electrolyte Membrane Fuel Cells

Abstract

The effect of H2S contamination on platinum catalyst in PEMFC has been investigated in terms of rotation disk electrode measurements in 0.1 M HClO4. The electrochemical surface area was determined by hydrogen underpotential deposition and CO stripping method before and after accelerated stress tests (AST). The observed losses of ECSA of the catalyst in the presence of H2S were associated to the adsorbed sulphur on the catalyst surface which changed cyclic voltammetric characteristics of the material.The RDE experiments revealed that ORR mass and specific activities were essentially decreased after AST with H2S contamination attributed to the interstitial defect on platinum atom sites due to the adsorbed sulphur. The HR-TEM has not revealed any significant differences between the catalyst surface morphology before and after test while EDX mapping indicated higher amount of the sulphur after AST confirming the presence of adsorbed sulphur species on the platinum catalyst surface.