Electrochemical synthesis of Ni-S/CeO₂ composite electrodes for hydrogen evolution reaction

Ni-S/CeO₂ electrodes have been prepared by a composite electrodeposition technique using nickel sulfaminate bath containing suspended micro- or nano-sized CeO₂ particles. The composite electrodes exhibit a high activity for the hydrogen evolution reaction (HER) in alkaline solutions, most likely due to the synergistic effects between Ni and CeO ₂, as well as the increased surface area of the electrodes upon addition of CeO₂ particles. It is found that the addition of CeO ₂ particles can lead to an increase of the sulphur content, resulting in more amorphous structures in the composite coatings. The Ni-S/micro-CeO ₂ composite electrode yields a higher HER activity than that measured with Ni-S/nano-CeO₂ electrode, which is 2.2 times higher than that on the Ni-S coating. The relevant discussion was provided to elucidate the promotional roles of CeO₂ particles in the composite electrodeposition process and corresponding HER activity.