The intrinsic catalytic activity of MOFs often originates from the unsaturated metal active sites serving as Lewis acids for heterogeneous catalysis. However, the activity of metal components of Zr-MOFs is seriously weakened by the fully saturated eight-coordination-environment of each zirconium atom in the frameworks [
11]. Defect engineering, referring to the application of controlled defects (such as vacancies, dopants and lattice disorders), has recently been applied to create unsaturated metal sites in the metal oxides and MOFs for improving electrocatalysis and heterogeneous catalysis, respectively. Missing linker in the structure is an effective strategy to create defects for improving the catalytic performance of MOFs. For instance, De Vos
et al. [
15] demonstrated that pristine UiO-66 almost displayed no activity for the Meerwein reduction of 4-
tert-butylcyclohexane with isopropanol (only 5% conversion after 24 h), whereas, the conversion rate reached 70% for defective UiO-66. Van Speybroeck
et al. [
16,
17] further confirmed the condensation reaction of benzaldehyde and heptyl crossol aldehyde was only carried out for UiO-66 with ligand vacancies and consequent unsaturated Lewis acid sites on Zr
4+ by combination of experimental and theoretical studies. Typically, ligand vacancies can be created through the "
de novo" synthesis and postsynthetic treatment [
18]. De Vos
et al. developed a modulation approach to create linker vacancies within UiO-66 in the presence of trifluoroacetic acid and HCl during the synthesis, which significantly promote the conversion of citronellal to 3-methyl-1,3-butanediol compared with UiO-66 synthesized without the modulator [
15]. Feng
et al. [
19] employed a hemilabile linker (4-sulfonatobenzoate) to synthesize a hemilabile UiO-66, the defects of which could be created through a postsynthetic treatment with H
2SO
4. Liang
et al. [
20] promoted the formation of ultrafine metal oxide nanoparticles by thermal decomposition of the linker, ultrasmall metal oxide nanoparticles immobilized in an open framework that exhibits high catalytic activity for Lewis acid-catalyzed reactions. Nonetheless, the postsynthetic treatment is not achievable for directly producing defects within pristine UiO-66 by consideration of the robust stability even within acidic solutions. Now, we develop a microwave-assisted acid-induced post-treated method for formation of linker vacancies within Zr-based metal organic frameworks. The physical characterization proves that the MOF materials with abundant unsaturated metal active sites can be obtained by this post-treatment method. Therefore, these MOF materials have better catalytic performance.