Highly active and CO2 tolerant Ir nanocatalysts for H-2/CO2 separation in electrochemical hydrogen pumps

Abstract

Carbon-supported Pt nanoparticles have been widely used as electrocatalysts for electrochemical hydrogen pumps. However, Pt surfaces are susceptible to poisoning under CO2 atmosphere, and as a result, need greater applied cell voltages. Instead of Pt as an anode catalyst in electrochemical hydrogen pumps, we synthesized Ir-based catalysts and characterized them by XRD, XPS, TEM, and TGA. The electrochemical characteristics of the Ir catalysts were evaluated by a halfcell test, and their catalytic activities toward the hydrogen oxidation and hydrogen evolution reactions were evaluated by micro polarization analysis. The exchange current density of the Ir catalyst that was heat treated at 300 degrees C was larger than that of commercial Pt. CO2 stripping analysis confirmed that the Ir catalyst was not affected by CO2, unlike the Pt catalyst. Focusing on H-2 separation from H-2/CO2 gas, an evaluation using a single-cell test indicated that the Ir catalyst performed better than the Pt catalyst. (C) 2014 Elsevier B.V. All rights reserved.