Tungsten carbide is investigated as cathode in the electrocatalytic water splitting in molten CsH2PO4 in the medium temperature range from 350 to 390 degrees C. The electrocatalytic activity of tungsten carbide improves with increasing temperature and at 390 degrees C surpasses that of platinum. Hydrogen is formed during the electrolysis as confirmed by Raman spectroscopy. The tungsten carbide coating of the electrode is stable during electrolysis for at least 63 min at 350 degrees C and undergoes no apparent change even at 390 degrees C. The use of molten CsH2PO4 as electrolyte in the medium temperature range allows for the development of abundant and cheap catalysts for the electrochemical water splitting. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.