A molecular-level picture clearly describing the dynamic interfacial interactions with their correlation to CO ₂ RR properties is established, which enables us to spatially and temporally understand electrochemical reactions at the solid–liquid interface.

In this work, we have systematically investigated the HER activity of RE₂Co₁₇. We discovered that lanthanide contraction can regulate the HER activity of iron triad intermetallics in alkaline media.

Noble metals (e.g., Ru, Ir and Pt) or their derivatives exhibit very appealing activity toward the hydrogen evolution reaction (HER), but their high price and low reserves impede their wide use. Herein, we propose a strategy in which, through the manipulation of crystal and electronic structure, one can convert a common metal to have a Pt-like performance for HER. To achieve this goal, a series of MCo₂ (M = Ti, Zr, Hf and Sc) has been synthesized by using a rapid arc-melting method. TiCo₂ exhibits comparable HER activity to that of Pt/C, for which it requires only −70 mV (V vs. RHE) to reach 10 mA cm⁻² with a Tafel slope of 33 mV decade⁻¹ in 1.0 M KOH. Moreover, X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) indicate that the lower adsorption energy (ΔG_H*) of H on the Co atom in TiCo₂, due to the change in Co electronic state, is another key factor to account for its high HER activity. This case study offers a good illustration of how to transform a non-noble metal so it behaves like a noble metal toward HER and can potentially be applied under other conditions.