Electronic‐Steric Synergy of Branched Ligands on Palladium for Boosted CO 2 Electroreduction

ABSTRACT The electronic‐steric impacts of ligands on metal surface are inherently interrelated and often act in concert for CO 2 electroreduction (CO 2 RR), but the crucial role of steric hindrance on CO 2 RR kinetics is always overlooked, and an in‐depth understanding of their trade‐off between kinetics and thermodynamics is still lacking. Here we assembled linear oleylamine (OAm) and n‐butylamine (BAm) ligands, and branched diethylamine (DEA) and triethylamine (TEA) ligands on palladium nanoparticles (Pd NPs) to study their electronic‐steric configuration impacts on CO 2 RR activity. Computational calculations based on electronic configuration from a thermodynamic perspective revealed that linear BAm‐Pd NPs favored *COOH adsorption and *CO desorption the most, but branched DEA‐Pd NPs rather than linear BAm‐Pd NPs achieved the largest j CO and the highest FE CO over 99% across the entire potential range. Molecular dynamics simulations and contact angle tests demonstrated that ligands underwent self‐adaption with local densities of CO 2 and H 2 O molecules on Pd NPs, and DEA reached a trade‐off between steric hindrance and electronic configuration, where moderate hydrophobic surface and steric hindrance accelerated CO 2 dissolution and diffusion, while electron‐donating amine transferred more electrons to Pd─CO antibonding orbital for better CO release. This study unravels the crucial roles of electronic‐steric configurations of amine‐containing ligands for electrocatalysis.