Engineering Steric‐Hindrance‐Guided Crystalline Vacancies in a Scalable Pillared‐Layer Nickel‐MOF for Efficient Gas Uptake and Separation

ABSTRACT Engineering local vacancies in metal–organic frameworks (MOFs) presents a promising route to high‐performance gas adsorption/separation, yet conventional defect engineering often yields statistically distributed vacancies. Here, we report a steric‐hindrance‐programmed strategy to construct periodically ordered vacancies in pillared‐layer LIFM‐Ni‐3‐H 2 O via de novo synthesis by changing pyrazine linkers in a full‐pillared reference TJE‐1 to bulkier triethylenediamine ligands, resulting in missing‐pillars to produce potential vacancies in a regularly staggered interlayer fashion. Single‐crystal x‐ray diffraction unambiguously identifies the alternating pillar/vacancy arrangement, and digestion 1 H NMR supports overall stoichiometry. Removing capped water molecules converts LIFM‐Ni‐3‐H 2 O into LIFM‐Ni‐3 with complete exposure of the open‐metal Ni 2+ ‐sites, reshaping the local pore to form a contracted Window‐I and an enlarged Window‐II bearing open‐metal sites for molecular accessing and binding. LIFM‐Ni‐3 enables efficient separation processes: adsorbing SF 6 at Window‐II with 2.64 mmol g −1 uptake at 0.1 bar while excluding N 2 , and purifying CH 4 by removing minor C 2 H 6 /C 3 H 8 from natural gas with an exceptional productivity of 13.5 mmol g −1 . This represents a rare example that features simultaneously high capacity and selectivity by overcoming capacity–selectivity trade‐off, and combines favorable low‐pressure capture with fast apparent uptake responses. The scale‐up experiment testifies reliability of this pillar‐displacing approach for mass production and scalable gas separation.