2.2. MOFs with Metal Active Sites 4614 2.2.1. Early Studies 4614 2.2.2. Hydrogenation Reactions 4618 2.2.3. Oxidation of Organic Substrates 4620 2.2.4. CO Oxidation to CO2 4626 2.2.5. Phototocatalysis by MOFs 4627 2.2.6. Carbonyl Cyanosilylation 4630 2.2.7. Hydrodesulfurization 4631 2.2.8. Other Reactions 4632 2.3. MOFs with Reactive Functional Groups 4634 2.4. MOFs as Host Matrices or Nanometric Reaction Cavities 4636

Engineering Metal Organic Frameworks for Heterogeneous Catalysis

This review summarizes the use of metal–organic frameworks (MOFs) as a versatile supramolecular platform to develop heterogeneous catalysts for a variety of organic reactions, especially for liquid-phase reactions. Following a background introduction about catalytic relevance to various metal–organic materials, crystal engineering of MOFs, characterization and evaluation methods of MOF catalysis, we categorize catalytic MOFs based on the types of active sites, including coordinatively unsaturated metal sites (CUMs), metalloligands, functional organic sites (FOS), as well as metal nanoparticles (MNPs) embedded in the cavities. Throughout the review, we emphasize the incidental or deliberate formation of active sites, the stability, heterogeneity and shape/size selectivity for MOF catalysis. Finally, we briefly introduce their relevance into photo- and biomimetic catalysis, and compare MOFs with other typical porous solids such as zeolites and mesoporous silica with regard to their different attributes, and provide our view on future trends and developments in MOF-based catalysis.

Applications of metal–organic frameworks in heterogeneous supramolecular catalysis

This review surveys recent advances in the applications of layered double hydroxides (LDHs) in heterogeneous catalysis. By virtue of the flexible tunability and uniform distribution of metal cations in the brucite-like layers and the facile exchangeability of intercalated anions, LDHs-both as directly prepared or after thermal treatment and/or reduction-have found many applications as stable and recyclable heterogeneous catalysts or catalyst supports for a variety of reactions with high industrial and academic importance. A major challenge in this rapidly growing field is to simultaneously improve the activity, selectivity and stability of these LDH-based materials by developing ways of tailoring the electronic structure of the catalysts and supports. Therefore, this Review article is mainly focused on the most recent developments in smart design strategies for LDH materials and the potential catalytic applications of the resulting materials.

Catalytic applications of layered double hydroxides: recent advances and perspectives

Adsorptive removal of hazardous materials using metal-organic frameworks (MOFs): A review

Research interest in biomass conversion to fuels and chemicals has increased significantly in the last decade as the necessity for a renewable source of carbon has become more evident. Accordingly, many different reactions and processes to convert biomass into high-value products and fuels have been proposed in the literature. Special attention has been given to the conversion of lignocellulosic biomass, which does not compete with food sources and is widely available as a low cost feedstock. In this review, we start with a brief introduction on lignocellulose and the different chemical structures of its components: cellulose, hemicellulose, and lignin. These three components allow for the production of different chemicals after fractionation. After a brief overview of the main reactions involved in biomass conversion, we focus on those where bimetallic catalysts are playing an important role. Although the reactions are similar for cellulose and hemicellulose, which contain C6 and C5 sugars, respectively, different products are obtained, and therefore, they have been reviewed separately. The third major fraction of lignocellulose that we address is lignin, which has significant challenges to overcome, as its structure makes catalytic processing more challenging. Bimetallic catalysts offer the possibility of enabling lignocellulosic processing to become a larger part of the biofuels and renewable chemical industry. This review summarizes recent results published in the literature for biomass upgrading reactions using bimetallic catalysts.

Bimetallic catalysts for upgrading of biomass to fuels and chemicals

CO2 adsorption and catalytic application of Co-MOF-74 synthesized by microwave heating

Selective oxidation of tetralin over a chromium terephthalate metal organic framework, MIL-101

Oxidative desulfurization of 4,6-dimethyl dibenzothiophene and light cycle oil over supported molybdenum oxide catalysts

Molybdenum disulfide (MoS2), which is composed of active edge sites and a catalytically inert basal plane, is a promising catalyst to replace the state-of-the-art Pt for electrochemically catalyzing hydrogen evolution reaction (HER). Because the basal plane consists of the majority of the MoS2 bulk materials, activation of basal plane sites is an important challenge to further enhance HER performance. Here, an in situ electrochemical activation process of the MoS2 basal planes by using the atomic layer deposition (ALD) technique to improve the HER performance of commercial bulk MoS2 is first demonstrated. The ALD technique is used to form islands of titanium dioxide (TiO2) on the surface of the MoS2 basal plane. The coated TiO2 on the MoS2 surface (ALD(TiO2)-MoS2) is then leached out using an in situ electrochemical activation method, producing highly localized surface distortions on the MoS2 basal plane. The MoS2 catalysts with activated basal plane surfaces (ALD(Act.)-MoS2) have dramatically enhanced HER kinetics, resulting from more favorable hydrogen-binding.

In Situ Electrochemical Activation of Atomic Layer Deposition Coated MoS2 Basal Planes for Efficient Hydrogen Evolution Reaction

A series of ordered mesoporous silica (OMS) supported tantalum oxide samples (Ta/OMS) were tested as catalysts for the production of 1,3-butadiene (BD) from ethanol and acetaldehyde. To study the influence of the type of mesostructure, the pore size, and the particle morphology on the performance of the catalyst, Ta/OMS catalysts were prepared using two different mesostructured silica supports (2-D hexagonal SBA-15 and 3-D cubic KIT-6) and five different 2-D hexagonal OMS supports (SBA-15 series and MMS) with varied mesopore diameters in the range of 2.5–10.9 nm. The obtained Ta/OMS catalysts were characterized by a nitrogen physisorption analysis and X-ray diffraction, as well as by scanning electron micrography. The catalytic results showed that the pore size and crystal size of OMS samples are more important than mesopore structure such as pore dimension and pore shape to optimize the catalytic performance of Ta/OMS catalysts for BD production from ethanol and acetaldehyde.

Soon-Yong Jeong

Papers

CO2 adsorption and catalytic application of Co-MOF-74 synthesized by microwave heating

Selective oxidation of tetralin over a chromium terephthalate metal organic framework, MIL-101

Oxidative desulfurization of 4,6-dimethyl dibenzothiophene and light cycle oil over supported molybdenum oxide catalysts

In Situ Electrochemical Activation of Atomic Layer Deposition Coated MoS2 Basal Planes for Efficient Hydrogen Evolution Reaction

Butadiene production from bioethanol and acetaldehyde over tantalum oxide-supported ordered mesoporous silica catalysts