A novel approach for the preparation of Ni-CeO2 composite cathodes with enhanced electrocatalytic activity

In this work, supergravity fields were utilized to prepare Ni-CeO2 composite cathodes from a nickel sulphamate bath containing suspended nano-sized CeO2 particles. The prepared Ni-CeO2 composite coatings exhibit a significant enhancement in electrocatalytic activity for the hydrogen evolution reaction (HER) in alkaline solutions. The crystal structure, morphology and chemical compositions of the composite coatings were characterized by XRD, SEM and EDS measurements. It was shown that the prepared Ni-CeO2 composite coatings displayed a fine grain size and high contents of CeO2 incorporated into the Ni matrix. The electrochemical activity of the composite cathodes for HER was determined by polarization measurements and electrochemical impedance spectroscopy in 1.0 M NaOH solution. The results indicate that the catalytic activity of the Ni-CeO2 composite coatings is enhanced significantly, and the highest value of the exchange current density reaches 338.4 mu A cm(-2), which is obviously higher than the values previously reported in the literature. Meanwhile, the effects of both the CeO2 concentration and the intensities of the supergravity fields on the properties of the Ni-CeO2 coatings are investigated.