Unsupported nickel was evaluated as an electrocatalyst material in an electrochemical hydrogen pump using the superprotonic solid acid CsH2PO4 as a proton exchange membrane. In humidified hydrogen at 250 degrees C, Ni-based electrodes display a stable proton reduction current of 207 mA cm(-2) at a -0.2 V cell potential. Electrodes utilizing carbon-supported Pt catalysts evolved hydrogen at 558 mA cm(-2) under identical conditions. Hydrogen evolution and oxidation are reversible on Pt, but hydrogen oxidation activity is virtually absent on Ni. (C) 2013 Elsevier B.V. All rights reserved.