Noble fabrication of Ni–Mo cathode for alkaline water electrolysis and alkaline polymer electrolyte water electrolysis

Abstract

Among the catalysts for hydrogen evolution reaction (HER) in alkaline media, Ni–Mo turns out to be the most active one. Conventional preparations of Ni–Mo electrode involve repeated spraying of dilute solutions of precursors onto the electrode substrate, which is time-consuming and usually results in cracking and brittle electrodes. Here we report a noble fabrication of Ni–Mo electrode for HER. NiMoO4 powder was synthesized and used as the precursor. After reduction in H2 at 500 °C, the NiMoO4 powder layer was converted to a uniform and robust electrode containing metallic Ni and amorphous Mo(IV) oxides. The distribution of Ni and Mo components in this electrode is naturally uniform, which can maximize the interaction between Ni and Mo and benefit the electrocatalysis. The thus-obtained Ni–Mo electrode exhibits a very high catalytic activity toward the HER: the current density reaches 700 mA/cm2 at 150 mV overpotential in 5 M KOH solution at 70 °C. This new fabrication method of Ni–Mo electrode is not only suitable for alkaline water electrolysis (AWE), but also applicable to the alkaline polymer electrolyte water electrolysis (APEWE), an emerging technique for efficient production of H2.