Preparation and characterization of nanocrystalline Ni-Mo as cathode catalyst via RF magnetron sputtering

Ni-Mo alloy thin film was prepared by RF magnetron sputtering method, and the film was used as cathode catalyst in photoelectrochemical hydrogen production from solar energy firstly. The crystallinity, composition, surface morphology and crystalline size were characterized by XRD, EDS, SEM and AFM experiments. The electrochemical behavior of the film were studied by steady-state polarization plots and electrochemical impedance spectroscopy. The results mentioned above show that under the conditions of the higher working pressure, lower substrate temperature and the longer target distance the Ni-Mo alloy thin film obtained possesses a good electrocatalytic activity. Additionally, the electrocatalytic activity of the film was also enhanced with the decreasing of crystalline size and increasing of molybdenum content. The hydrogen overpotential of hydrogen evolution reaction is 177.7 mV at current density 100 mA/cm(2). The rate-limiting step was electrochemical desorption.