Molecular catalysts serve as ideal platforms for studying electrocatalytic reaction mechanisms. While current research mainly focuses on modulating central metals or surrounding ligands, the influence of molecular spatial configuration remains largely unexplored. Herein, we synthesized two cobalt complexes with similar ligand environments but distinct spatial geometries, a planar cobalt hexaazamacrocyclic complex (CoHAM) and a non-planar acyclic Co(phen)₂Cl₂, and evaluated their performance in CO₂ reduction reaction (CO₂RR). The planar CoHAM exhibited dramatically superior CO₂RR performance compared to the non-planar Co(phen)₂Cl₂. Through a series of combined analyses using in-situ UV-vis spectroscopy, high-resolution mass spectrometry (HRMS), and Raman spectroscopy, we elucidated the origins of this performance gap by identifying key intermediates and reaction pathways. These findings underscore the critical role of the spatial configuration of molecular catalysts in governing electrocatalytic performance and provide a strategic direction for the rational design of efficient CO₂RR catalysts.

The electrochemical reduction of CO₂ to multi-carbon (C₂₊) products is a promising strategy for sustainable fuel and chemical production and CO₂ emission mitigation. However, optimizing *CO intermediate generation and utilization in complex multi-electron systems is crucial for the C₂ products, but it remains challenging. Herein, we synthesize a yolk-shell structured Cu@HCS catalyst via hydrothermal synthesis coupled with high-temperature calcination, featuring a unique copper core and hollow carbon shell nanostructure. This architecture significantly enhances the selectivity toward C₂ products during electrocatalytic CO₂ reduction. The optimized Cu@HCS-2-800 catalyst achieves a Faradaic efficiency (FE) of 69.7% for C₂ products at –1.4 V vs. reversible hydrogen electrode (RHE), markedly surpassing the 30.1% FE of conventional Cu/xc-72 catalyst. Furthermore, the yolk-shell configuration suppresses hydrogen evolution, ensuring superior stability during prolonged operation. In situ attenuated total reflectance-surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) and density functional theory (DFT) analysis reveal that the Cu@HCS-2-800 catalyst leverages spatial confinement effects to retard CO diffusion and promote CO re-adsorption, thereby elevating *CO intermediate coverage to enhance C–C coupling. This work underscores the pivotal role of nanoscale spatial confinement in advancing CO₂ electroreduction performance and provides a guidance for designing advanced catalysts with tailored microenvironment.