Hydrophilic swellable metal–organic framework encapsulated Pd nanoparticles as an efficient catalyst for Cr(vi) reduction

Abstract

Controllable integration of metallic nanoparticles and metal-organic frameworks (MOFs) may create a new material with multifunctional applications. In this work, an emerging type of core-shell nanostructure, in which the metallic Pd nanoparticles cores were encapsulated by the MOF (ZIF-67) shells, was facilely synthesized through an impregnationreduction process. The as-synthesized Pd@ZIF-67 material, with highly dispersed Pd nanoparticles encapsulated in the porous ZIF-67 structure, exhibited favorable catalytic performance towards the formic acid (HCOOH)-induced reduction of highly toxic hexavalent chromium (Cr(VI)). In this process Cr(VI) was converted the to Cr(III) within 5 min, and the material could be reused for 10 times without significant loss of its catalytic activity. The highly hydrophilic and swellable nature of the ZIF-67 was proposed to be responsible mainly for the favorable durability of the Pd@ZIF-67. The results provided in this work may pave a way for the concise preparation of nano-hybrid catalysts with high performance and durability for the pollutants elimination.An emerging type of core-shell nanostructure, in which the metallic Pd nanoparticles cores were encapsulated by the MOF (ZIF-67) shells, was facilely synthesized through an impregnation-reduction process

Well‐Arranged and Confined Incorporation of PdCo Nanoparticles within a Hollow and Porous Metal–Organic Framework for Superior Catalytic Activity

“…For example, Jiang and co‐workers have reported the incorporation of Pd nanoparticles within a MOF for the catalytic reduction of 4‐nitrophenol . Yu and co‐workers demonstrated that the encapsulation of Pd nanoparticles within a MOF results in a highly efficient Cr VI reduction activity . Meanwhile, several methods have been developed to create hybrid MOFs containing two or more components or functions for the enhanced utilizations of MOFs by providing extra stability or functionality .…”

Nanoparticle/Metal–Organic Framework Composites for Catalytic Applications: Current Status and Perspective

“…The resulting composites exhibit favorable catalytic performance, as demonstrated by the short time of complete reduction of Cr(VI) into Cr(III). Importantly, Yu et al [ 152 ] proposed a reasonable mechanism for the catalytic reduction of Cr(VI) into Cr(III), as evidenced by a series of experiments. Formic acid is first adsorbed on the surface of metal NPs, and is then is dehydrogenated to produce H 2 and CO 2 , according to Equation (1).…”

“…Among the physical, chemical, and biological technologies that are applied for the removal of pollutants, heterogeneous catalysis, including photocatalysis, has been demonstrated to be an efficient, economical, and green technique to degrade pollutants into easily biodegradable or less toxic compounds. Recently, MOF based composites with noble metal NPs, metal oxide/sulfides, GO, and other compounds have been proved to be a new class of catalysts, which are usable in the catalytic degradation of organic pollutants and Cr(VI) [ 138 , 139 , 140 , 141 , 142 , 143 , 144 , 145 , 146 , 147 , 148 , 149 , 150 , 151 , 152 , 153 , 154 , 155 , 156 , 157 , 158 , 159 ].…”

“…Xu, Yu and Trivedi’s groups reported active MOF-supported noble metal (Pt, Pd) NPs catalysts for the reduction of Cr(VI) to Cr(III) using formic acid [ 145 , 152 , 157 ]. The resulting composites exhibit favorable catalytic performance, as demonstrated by the short time of complete reduction of Cr(VI) into Cr(III).…”

Removal of Congo red and malachite green from aqueous solution using heterogeneous Ag/ZnCo-ZIF catalyst in the presence of hydrogen peroxide

“…Hybrid ZIF materials are also attracting many scientists because of their potential applications. In particular, the combination of ZIFs and metal nanoparticles can create a new material that integrates the advantages of each individual component, such as synthesis of Pd/ZIF-8 material using a simple route with liquid impregnation and chemical reduction methods [26], synthesis of Pd@ZIF-67 for Cr reduction from highvalent ion(VI) to low-valent ion(III) with high catalytic activity and excellent cycle durability [27], and synthesis of Ag/ZIF-67 using a simple impregnation method applying for degradation reaction of methyl orange in the presence of hydrogen peroxide with excellent efficiency [28].…”