Synergistic Electric Field and Confinement Effects in Porous Cu2O Octahedra Enable CO2 Electroreduction across pH Conditions.

Conventional catalyst design for CO2 electroreduction is fundamentally constrained by the pH of the bulk electrolyte as it affects catalyst durability, reaction pathways, and overall performance. Herein, we break this paradigm by using three-dimensional ordered porous Cu2O octahedra (3DOP Cu2O-OC) to decouple the local reaction microenvironment from the bulk electrolyte. This architecture synergistically integrates a built-in electric field and nanoconfinement effects, which work in concert to enrich electrolyte cations and enhance local CO2 concentration, thereby creating a stable microenvironment independent of the electrolyte pH. Moreover, the C-C coupling reaction via forming a *OCCOH intermediate is kinetically promoted at the defective Cu+/Cu0 interface sites confined in the nanopores. Leveraging these synergistic effects, 3DOP Cu2O-OC achieves high Faradaic efficiencies of 84.0 ± 1.0% in alkaline and 74.0 ± 0.2% in acidic electrolytes for multicarbon products at current densities up to -1.0 and -0.8 A cm-2, respectively. This work establishes a general design model for creating adaptive microenvironments by leveraging synergistic physical effects within nanoarchitectures, providing an important design principle for universal electrocatalyst design.