Titanium hydrides form simultaneously with the occurrence of the hydrogen evolution reaction. The electrochemical properties of titanium hydrides generated by cathodic galvanostatic polarization in a simulated acidic leaching solution were investigated. The titanium hydrides were found to catalyze the hydrogen evolution reaction and facilitate the subsequent passivation of Ti-2. X-ray diffraction results revealed that the galvanostatically-formed hydrides were primarily composed of TiH1.5, with small amounts of TiH1.7 and TiH2. The preferential formation of TiH1.5 is discussed in this work. (C) The Author(s) 2019. Published by ECS.