title: Electrochemical Synthesis and Catalytic Properties of Encapsulated Metal Clusters within Zeolitic Imidazolate Frameworks.
abstract: It is very interesting and also a big challenge to encapsulate metal clusters within microporous solids to expand their application diversity. For this target, herein, we present an electrochemical synthesis strategy for the encapsulation of noble metals (Au, Pd, Pt) within ZIF-8 cavities. In this method, metal precursors of AuCl42-, PtCl62-, and PdCl42-are introduced into ZIF-8 crystals during the concurrent crystallization of ZIF-8 at the anode. As a consequence, very small metal clusters with sizes around 1.2 nm are obtained within ZIF-8 crystals after hydrogen reduction; these clusters exhibit high thermal stability, as evident from the good maintenance of their original sizes after a high-temperature test. The catalytic properties of the encapsulated metal clusters within ZIF-8 are evaluated for CO oxidations. Because of the small pore window of ZIF-8 (0.34 nm) and the confinement effect of small pores, about 80 % of the metal clusters (fractions of 0.74, 0.77, and 0.75 for Au, Pt, and Pd in ZIF-8, respectively) retain their catalytic activity after exposure to the organosulfur poison thiophene (0.46 nm), which is in contrast to their counterparts (fractions of 0.22, 0.25, and 0.20 for Au, Pt, and Pd on the SiO2support). The excellent performances of metal clusters encapsulated within ZIF-8 crystals give new opportunities for catalytic reactions.
authors.affiliation: College of Chemistry, Jilin University, Changchun, 130012, P. R. China.
authors.forename: Pengyuan
authors.initials: P
authors.lastname: Wang
authors.affiliation: College of Chemistry, Jilin University, Changchun, 130012, P. R. China. jia@jlu.edu.cn.
authors.forename: Jia
authors.initials: J
authors.lastname: Liu
authors.affiliation: Faculty of Chemistry, Northeast Normal University, Changchun, 130024, P. R. China.
authors.forename: Chuanfang
authors.initials: C
authors.lastname: Liu
authors.affiliation: College of Chemistry, Jilin University, Changchun, 130012, P. R. China.
authors.forename: Bin
authors.initials: B
authors.lastname: Zheng
authors.affiliation: Faculty of Chemistry, Northeast Normal University, Changchun, 130024, P. R. China. zouxq100@nenu.edu.cn.
authors.forename: Xiaoqin
authors.identifier: http://orcid.org/0000-0002-8401-5538
authors.initials: X
authors.lastname: Zou
authors.affiliation: College of Chemistry, Jilin University, Changchun, 130012, P. R. China.
authors.forename: Mingjun
authors.initials: M
authors.lastname: Jia
authors.affiliation: College of Chemistry, Jilin University, Changchun, 130012, P. R. China.
authors.forename: Guangshan
authors.initials: G
authors.lastname: Zhu
keywords: CO oxidation; electrochemical synthesis; encapsulation; metal-organic frameworks; noble metal clusters