Ligand Protection Strategy for Highly Selective and Stable Electrochemical CO 2 Methanation

ABSTRACT The large‐scale electrochemical CO 2 methanation represents a promising route toward carbon neutrality. The construction of efficient catalytic sites and the maintenance of the site stability are crucial to achieving high‐efficiency conversion of CO 2 ‐to‐CH 4 . Herein, we design a La 2 O 3 ‐supported oxygen‐containing Cu clusters functionalized with hexanethiol (HT) molecules catalyst (HT@O‐Cu c /La 2 O 3 ), achieving a high CH 4 Faradaic efficiency (FE CH4 ) of 77.8% with a partial current density of 389.2 mA cm −2 , and demonstrating excellent stability over a 250 h operation period. The thiol‐ligand was modified at the interface between O‐Cu c and La 2 O 3 via S‐coordination, enabling electron transfer between La and Cu sites and establishing a stable electronic supplementary channel that continuously stabilizes the low‐coordinated Cu δ+ (0.4 < δ < 0.5) active state during the electrochemical process. Moreover, mechanistic studies reveal that the ligand modification optimizes *CO adsorption on Cu sites and steers *CHO hydrogenation toward *CH 2 OH. The electronic channel effect can strengthen the bond energy of Cu–C, facilitating the desorption of *OH. The La‐mediated water activation generates abundant protons, which drives the *CH 2 ─*CH 3 ─*CH 4 directional hydrogenation step, ultimately achieving highly selective CH 4 production.