Palladium metallated shell layer of shell@core MOFs as an example of an efficient catalyst design strategy for effective olefin hydrogenation reaction

Facile strategies for noble metal dispersion in the shell-layer of core–shell structured metal–organic frameworks based on Zr-MOFs (UiO-66@Pd-UiO-67-BPY) was developed. The robust structure of the core-structure UiO-66 was firstly synthesized before covering up with a shell-structure of UiO-67-BPY obtaining the core–shell structure (UiO-66@UiO-67-BPY). The metallation with active palladium species (Pd^II) was designed on the shell-layer of core–shell MOFs via a post-synthetic method. The Pd species were coordinated explicitly in a bidentate manner to the bipyridyl linkers of the shell-structure (UiO-67-BPY). Excellent dispersion of Pd in the shell structure was obtained, resulting in UiO-66@Pd-UiO-67-BPY, as confirmed from characterizations. Taking advantage of the designed catalyst, the synthesized UiO-66@Pd-UiO-67-BPY was examined for the catalytic hydrogenation reaction. The results revealed an excellent catalytic performance of UiO-66@Pd-UiO-67-BPY compared with the traditional catalyst Pd-UiO-67-BPY. Moreover, the designed catalyst structure exhibited outstanding performance and paved the way towards a cost-effective catalyst synthesis based on MOFs combined with a noble metal.