Metal Nanoparticles Covered with a Metal–Organic Framework: From One-Pot Synthetic Methods to Synergistic Energy Storage and Conversion Functions

Abstract

Hybrid materials composed of metal nanoparticles and metal-organic frameworks (MOFs) have attracted much attention in many applications, such as enhanced gas storage and catalytic, magnetic, and optical properties, because of the synergetic effects between the metal nanoparticles and MOFs. In this Forum Article, we describe our recent progress on novel synthetic methods to produce metal nanoparticles covered with a MOF (metal@MOF). We first present Pd@copper(II) 1,3,5-benzenetricarboxylate (HKUST-1) as a novel hydrogen-storage material. The HKUST-1 coating on Pd nanocrystals results in a remarkably enhanced hydrogen-storage capacity and speed in the Pd nanocrystals, originating from charge transfer from Pd nanocrystals to HKUST-1. Another material, Pd-Au@Zn(MeIM)2 (ZIF-8, where HMeIM = 2-methylimidazole), exhibits much different catalytic activity for alcohol oxidation compared with Pd-Au nanoparticles, indicating a design guideline for the development of composite catalysts with high selectivity. A composite material composed of Cu nanoparticles and Cr3F(H2O)2O{C6H3(CO2)3}2 (MIL-100-Cr) demonstrates higher catalytic activity for CO2 reduction into methanol than Cu/γ-Al2O3. We also present novel one-pot synthetic methods to produce composite materials including Pd/ZIF-8 and Ni@Ni2(dhtp) (MOF-74, where H4dhtp = 2,5-dihydroxyterephthalic acid).

Metal–Organic Frameworks Encapsulating Active Nanoparticles as Emerging Composites for Catalysis: Recent Progress and Perspectives

“…However, small‐sized active NPs have high surface energy and tend to migrate and aggregate into larger particles during the catalytic processes, thus leading to loss of the unique properties registered in the original active NPs. To address the above, one of the effective strategies is to encapsulate active NPs by porous MOFs to form core–shell or raisin‐bun typed structures, because crystal MOFs characteristic with uniform and long‐range ordered cavities could effectively promote the mass transfer and diffusion of substrates and products compared with conventional porous materials. Moreover, in the composite structures, the interfacial area of active NPs and MOFs is maximized, thus strengthening the interaction and electronic transfer between them and generating the intriguing properties for catalysis, especially for selective catalysis.…”

A Novel Nanocomposite with Superior Antibacterial Activity: A Silver‐Based Metal Organic Framework Embellished with Graphene Oxide

“…However, the position of the linkers completely depends on the metal coordination preferences. Benzene‐1,3,5‐tricarboxylic acid (BTC) and 1H‐1,2,4‐triazole are common ligands, and zinc, copper, and manganese are widely used metals for MOF synthesis . MOFs are synthesized via hydrothermal, solvothermal, solvent‐free, and chemical vapor deposition .…”

Electronic origin of hydrogen storage in MOF-covered palladium nanocubes investigated by synchrotron X-rays

“…The density of states (DOS) of palladium is composed of Pd 4d bands and 5s bands 10,11 . Theoretically, the hydrogen concentration in palladium is only related to the number of holes in the 4d band, because the transfer of H 1s electrons into Pd 4d holes creates Pd-H bonds 12,13 . As a representative MOF, HKUST-1 has a richly porous structure consisting of copper atoms interlinked organic 1, 3, 5-benzenetricarboxylate (BTC) frame ligands 14,15 .…”