Recent development on new anionic exchange membranes for alkaline membrane fuel cells has led to an increase on electrocatalyst testing measurements in three-electrode half-cells in alkaline media. However, there is not yet any commercial alkaline ionomer widely used, comparing to Nafion (R) in acidic media. In this work, two different commercial alkaline ionomers (12 from Acta and Fumion (R) FAA-3 from Fumatech) are tested. Different catalyst: ionomer ratios are employed in order to adjust the ink composition for a correct evaluation of the catalyst activity. For this purpose, a commercial 20 wt.% Pt/C catalyst was tested for CO electrooxidation and oxygen reduction reaction in thin layer RDE configuration. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.