Multi‐<i>d</i> Electron Synergy in LaNi_1‐<i>x</i>Co_<i>x</i>Ru Intermetallics Boosts Electrocatalytic Hydrogen Evolution

Abstract Despite the fact that d‐band center theory links the d electron structure of transition metals to their catalytic activity, it is yet unknown how the synergistic effect of multi‐d electrons impacts catalytic performance. Herein, novel LaNi 1‐x Co x Ru intermetallics containing 5d, 4d, and 3d electrons were prepared. In these compounds, the 5d orbital of La transfers electrons to the 4d orbital of Ru, which provides adsorption sites for H*. The 3d orbitals of Ni and Co interact with the 5d and 4d orbitals to generate an anisotropic electron distribution, which facilitates the adsorption and desorption of OH*. The synergistic effect of multi‐d electrons ensures efficient catalytic activity. The optimized LaNi 0.5 Co 0.5 Ru has an overpotential of 43mV at 10 mA cm −2 for alkaline electrocatalytic hydrogen evolution reaction. Beyond offering a variety of new electrocatalysts, this work reveals the multi‐d electron synergy in promoting catalytic reaction.