Nanoscale NiCu electrocatalyst for the hydrogen evolution reaction†

A molecular chemistry synthesis in solution under mild conditions provided a homogeneous nanometric NiCu nanomaterial stabilized by n-octysilane. The in-depth structural characterization by state-of-the-art techniques provided evidence for the formation of small nanoparticles of ca. 4.1 nm in size with an alloy-type structure. This nanomaterial was then easily deposited onto two different carbon supports, Vulcan and Ketjenblack, by impregnation. The electrocatalytic properties of both unsupported and supported NiCu nanomaterials have been investigated for their activity towards the hydrogen evolution reaction (HER) in alkaline conditions. The electrocatalytic properties indicate the advantageous addition of Cu to Ni as boosted HER performance and stability were observed. Also, the carbon-supported NiCu electrocatalysts presented higher performances as the result of increased conductivity and stabilization effects. Finally, an XPS study suggests that the n-octylsilane present at the surface of the NiCu nanoparticles may also intervene in their stabilisation under electrocatalytic conditions. The interest of developing synthesis protocols based on solution chemistry to have structurally controlled nanoscale materials in terms of size, composition, chemical order and surface state, criteria which can strongly influence the catalytic performances, is thus demonstrated in this work.