The alkaline water electrolysis is a promising method to store intermittent energy sources while producing green hydrogen efficiently. Among the different technologies available, anion exchange membrane (AEM) electrolyzers has the advantage of functioning with catalysts based on non-noble metals. Indeed, the use of alkaline medium provides suitable chemical stability for a large range of materials such as transition metals, which significantly reduces the AEM cost and allows a large-scale use. However, the performances and stability observed for AEM catalytic films are lower due to the sluggish water dissociation step occurring during the hydrogen evolution reaction (HER). Therefore, the concept of heterofunctional catalysts emerged as an efficient approach to combine the properties of active materials and create a synergy between them in order to promote the dissociation of water. To do so, members of our team developed a new family of heterofunctional catalysts based on large particles of nickel decorated by ruthenium nanoparticles. XPS results indicate that ruthenium is mostly observed on the nickel surface (see figure 1.a), which supports a heterogeneous structure. We carried out electrochemical characterizations (cyclic voltammetry measurements and electrolyzer test) and the results showed very high efficiencies for this family of materials (see figure 1.b), with performances similar to the platinum ones (60% Pt/C). The materials structure was also analyzed by operando X-Ray Absorption Spectroscopy (XAS) at the Ni and Ru K-edges to identify which metals are involved in the catalysis at low and high ruthenium content (see figure 1.c). In this presentation, the electrochemical and XAS results will be presented as well as the relationship between the structure and activity of these materials.