Spatial Electronic Partitioning in Metal-Organic Frameworks for pH-Universal CO2 Electroreduction

Precise control of the spatial proximity between reactive intermediates is critical for governing the C-C coupling kinetics during electrochemical CO2 reduction yet remains elusive. To address this challenge, the creatively spatial electronic partitioning is proposed to promote the intermediate proximity and thus facilitate efficient CO2 activation and distance-governed C-C coupling. The feasibility of this strategy is demonstrated in a series of copper-tetrazole metal-organic frameworks (MOFs, Cu-Tz-X, X = F, Cl, Br), which integrates coexisting free and halogen-confined cages. Within halogen-confined cages, the multidentate aromatic π faces cooperatively stabilize X anions through chelation-like noncovalent X···π interactions, polarizing the adjacent Tz linker into electrophilic domains while redistributing nucleophilic Cu sites. The halogen-induced electrophile-nucleophile electronic partition simultaneously promotes dual-site CO2 bending activation and enforces an optimal short-range *CO*CHO coupling distance, as evidenced by X-ray absorption spectroscopy, in situ FT-IR and theoretical simulations. Compared with halogen-free Cu-Tz-NO3, optimized Cu-Tz-Cl exhibits a reduced activation barrier, 10-fold enhancement in the C-C coupling rate, and a broad pH range catalytic stability. Remarkably, it maintains a high C2H4 FE of ∼61.3% even in a strongly acidic bulk electrolyte (pH = 1) at a total current density of 469 mA cm-2, outperforming previously reported MOF-based materials. This spatial electronic partitioning strategy establishes a well-defined catalytic microenvironment in confined catalytic systems toward efficient CO2 reduction.