Engineering nano-trap distribution in metal-organic frameworks enables boost of SF6/N2 separation

Separating/capturing SF 6 , having the strongest global warming potential, from exhaust gas with low concentration (1%-10%) in the power industry is significant for both greenhouse gas emission control and SF 6 recycling and reutilization. In this study, we achieved highly efficient SF 6 /N 2 separation under different SF 6 concentrations (1% and 10%) using two homologous metal-organic frameworks, Ni-bpz and Zn-bpz. This outcome underscores the effectiveness of rational nano-traps distribution engineering for targeted separation applications. The molecular simulation suggests that an SF 6 molecule interacts with a single nano-trap in Zn-bpz. At the same time, it is efficiently confined by two adjacent nano-traps in the parallel distribution of Ni-bpz. Consequently, exceptional SF 6 /N 2 selectivity for 1/99 and 10/90 mixtures have been respectively achieved in Ni-bpz (516, SF 6 /N 2 = 1/99) and Zn-bpz (608, SF 6 /N 2 = 10/90) at 298 K and 1 bar. In dynamic breakthrough experiments, Ni-bpz exhibits a record pure N 2 (≥ 99.99%) productivity (1496 mL/g) for an SF 6 /N 2 (1/99) gas mixture. Moreover, both MOFs demonstrate excellent water resistance across multiple cycles, suggesting their high promise for practical application. • The nano trap distribution strategy has been employed in two homologous MOFs to enhance SF 6 separation. • Highly efficient SF 6 /N 2 separation has been achieved under 1% and 10% SF 6 concentrations using Ni-bpz and Zn-bpz, respectively. • The computational study revealed the cooperative SF 6 binding with two adjacent nano traps of Ni-bpz. • The separation performance of both MOFs is maintained under humid conditions across multiple breakthrough cycles.