Immobilization of trigonal pyramidal copper(l) sites into  bibenzotriazole Metal-Organic Framework for efficient one-step methane purification

The production of high-purity CH 4 (>99.99%) is critical for energy and advanced industrial applications, but the simultaneous removal of N 2 and O 2 remains a significant challenge. Herein, we report a Cu(I) coordination-engineered metal–organic framework (Cu-CFA-1) based on theoretical design and experimental validation, which demonstrates remarkably selective adsorption of N 2 and O 2 over CH 4 , reversing the CH 4 selectivity of the parent material. In situ infrared spectroscopy and computational modeling studies revealed that the threefold coordination of Cu(I) by nitrogen ligands (Cu(I)-3N) significantly enhances its electron-donating capability, enabling targeted adsorption of π-acidic gases (N 2 /O 2 ) through charge-transfer effects. Breakthrough experiments demonstrated that Cu-CFA-1 can provide high-purity CH 4 in a single adsorption–desorption cycle from ternary (N 2 /O 2 /CH 4 ) and even six-component (N 2 /O 2 /CH 4 /CO 2 /C 2 H 6 /C 3 H 8 ) gas mixtures. This work provides an energy-efficient solution for CH 4 purification from multicomponent systems, and establishes a theoretical and practical foundation for the mechanism of π-acidic gas adsorption.