If the pore size of MOF is smaller than the POM size then encapsulation is impossible. But is their any chance of adsorption of POM on the surface of MOF making a composite?
Sure, there is. Of course the efficiency and extent of adsorption depends strongly both on the nature of the surface and the POM. See some examples below: http://pubs.rsc.org/en/Content/ArticleLanding/2012/SC/c2sc20210g#!divAbstract ; http://www.quimica.urv.es/w3qf/superficies/poms.html ; http://www.researchgate.net/publication/229064946_Functionalization_and_post-functionalization_A_step_towards_polyoxometalate-based_materials?enrichId=rgreq-e18da8a4-1753-496a-948b-6c5b11f7000a&enrichSource=Y292ZXJQYWdlOzIyOTA2NDk0NjtBUzo5OTQ0MDk1ODM3Nzk5NEAxNDAwNzE5OTgwMzcx&el=1_x_3 ; https://books.google.hu/books?id=FUqzig2p4PAC&pg=PA268&lpg=PA268&dq=adsorption+of+polyoxometalates+in+macroporous+materials&source=bl&ots=3-KuXznqbF&sig=ll0WD_7LZ_2haaKf9RO3AY1_jUY&hl=en&sa=X&ved=0CF0Q6AEwCGoVChMIy5bZlbSKxwIVyxEsCh1T6wML#v=onepage&q=adsorption%20of%20polyoxometalates%20in%20macroporous%20materials&f=false
Article Functionalization and post-functionalization: A step towards...