posted on 2022-02-03, 03:43authored byXiao-Wen Gu, Jia-Xin Wang, Enyu Wu, Hui Wu, Wei Zhou, Guodong Qian, Banglin Chen, Bin Li
Purification
of C2H4 from a ternary C2H2/C2H6/C2H4 mixture by
one-step adsorption separation is of prime importance
but challenging in the petrochemical industry; however, effective
strategies to design high-performance adsorbents are lacking. We herein
report for the first time the incorporation of Lewis basic sites into
a C2H6-selective MOF, enabling efficient one-step
production of polymer-grade C2H4 from ternary
mixtures. Introduction of amino groups into highly stable C2H6-selective UiO-67 can not only partition large pores
into smaller cagelike pockets to provide suitable pore confinement
but also offer additional binding sites to simultaneously enhance
C2H2 and C2H6 adsorption
capacities over C2H4. The amino-functionalized
UiO-67-(NH2)2 thus exhibits exceptionally high
C2H2 and C2H6 uptakes
as well as benchmark C2H2/C2H4 and C2H6/C2H4 selectivities, surpassing all of the C2H2/C2H6-selective materials reported so far. Theoretical
calculations combined with in situ infrared spectroscopy indicate
that the synergetic effect of suitable pore confinement and functional
surfaces decorated with amino groups provides overall stronger multipoint
van der Waals interactions with C2H2 and C2H6 over C2H4. The exceptional
performance of UiO-67-(NH2)2 was evidenced by
breakthrough experiments for C2H2/C2H6/C2H4 mixtures under dry and wet
conditions, providing a remarkable C2H4 productivity
of 0.55 mmol g–1 at ambient conditions.