Efficient CO₂ electroreduction requires catalysts for enhanced energy conversion efficiency and carbon product selectivity with low overpotential, in consideration of the interference of competitive H₂ evolution reaction and complex intermediate species involved. We proposed that adaptive electronic structures based on dynamic mixed-valence interconversion would facilitate electron transfer and intermediate turnover during the catalysis, ensuring high activity, selectivity, and durability. Herein, a novel mixed-valence Cu-based metal-organic framework was prepared using an electron-rich linker for electrocatalytic reduction of CO₂. The designed material delivered a remarkable Faradaic efficiency of 99.2% for C₁ liquid fuels at a low reduction potential of −0.1 V versus reversible hydrogen electrode, considerably higher than that of the commercial copper foam and competitive to the Cu-based electrocatalysts reported. The experimental data and theoretical calculations verified the Cu(I)/Cu(II) interconversion and the much higher energy barrier of H₂ evolution than carbon product generation. Such a feasible strategy, simultaneously improving energy conversion efficiency, carbon product selectivity, and structural robustness, provides great insights into rational catalyst customization for sustainable CO₂ conversion.

The regulation of gas sorption via simple pore modification is crucial to molecular recognition and chemical separation. Herein, a rational pore surface electrostatic modulation in synthetic one dimensioned (1D) channel is demonstrated to boost ethane/ethylene (C₂H₆/C₂H₄) selectivity for one-step extraction of C₂H₄ from C₂H₆/C₂H₄ mixtures. Through the precise modulation of the surface charge arrangement with negatively charged moieties in the 1D channel of a metal–organic framework (MOF), enhanced C₂H₆–host framework and decreased C₂H₄–host framework electrostatic interactions were obtained, which resulted in an obvious improvement in adsorption selectivity. Furthermore, the breakthrough separation performance rendered the obtained MOF an efficient adsorbent for C₂H₄ purification from C₂H₆/C₂H₄ mixture. The combined detail theoretical studies prove that the gas sorption selectivity is remarkably sensitive to framework electrostatic change even in the case of pore surface modification at the atomic level. These results are of fundamental importance to the design of porous materials for challenging separation tasks.