Enhancement of electrocatalytic activity towards hydrogen evolution reaction by boron-modified nickel nanoparticles

Nanosized nickel particles have been synthesized by three different routes: polyol, microemulsion and precipitation/reduction methods. Nickel nanoparticles have been evaluated as electrocatalysts for the hydrogen evolution reaction (HER). The electrocatalysts have been characterized by using X-ray diffraction (XRD), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Their electrocatalytic performance in the hydrogen evolution reaction has been evaluated by means of the Tafel curves recorded in alkaline medium. The activity for the hydrogen evolution reaction increases with the increasing amount of reduced Ni in the electrocatalysts. Remarkably, the formation of a nickel-boride alloyed phase (Ni3B) is responsible for the higher activity of the sample prepared by the precipitation/reduction method for the HER. The crystalline phase Ni3B appears to be responsible for the very high activity in hydrogen production.

► Nanosized nickel-boride alloyed phase (Ni3B) can be easily prepared by precipitation/reduction of nickel acetate with NaBH4.
►  Boride-modified nickel nanoparticles are endowed with very high activity in the hydrogen evolution reaction (HER).
► Formation of Ni3B phase is responsible for the higher activity for the HER.