Many electrochemical studies exist using the acidic ionomer Nafion as a binder in the ink formulation when operating in high pH systems. However, Nafion acts as an ionic insulator for OH-, and for reactions such as the hydrogen oxidation reaction, the transport of OH- to the catalyst surface is of utmost importance when elucidating the performance of a catalyst. This work demonstrates that when using an alkaline polymer binder in the ink, the apparent activity of a commercially synthesized Pt/C catalyst is increased due to a lower diffusion resistance for the reaction. In order to obtain accurate values for kinetic data in alkaline media, the use of the acidic binder should be avoided. (c) 2017 The Electrochemical Society. All rights reserved.