Enhanced Photocatalytic CO Reduction to Methanol over Eco-Friendly CuCo-ZIF@g-CN Synthesized from Recyclable Resources.

The present work is focused on designing a sustainable catalyst for the photocatalytic conversion of CO to methanol under visible light irradiation. Notably, most catalysts are made of costly, nonearth-abundant metal resources, which can partially hinder the large-scale implementation of CO utilization efforts. Thus, a highly efficient CuCo-ZIF@g-CN composite photocatalyst was prepared using copper sulfate (CuSO) and cobalt sulfate (CoSO) recovered from mining waste.

Non-van-der-Waals Oriented Two-Dimensional UiO-66 Films by Rapid Aqueous Synthesis at Room Temperature.

The synthesis of MOFs in a two-dimensional (2D) film morphology is attractive for several applications including molecular and ionic separation. However, 2D MOFs have only been reported from structures that crystallize in lamellar morphology, where layers are held together by van der Waals (vdW) interaction. By comparison, UiO-66, one of the most studied MOFs because of its exceptional chemical stability, has only been reported in three-dimensional (3D) morphology.

Unraveling metal effects on CO uptake in pyrene-based metal-organic frameworks.

Pyrene-based metal-organic frameworks (MOFs) have tremendous potential for various applications. With infinite structural possibilities, the MOF community often relies on simulations to identify the most promising candidates for given applications. Among thousands of reported structures, many exhibit limited reproducibility - in either synthesis, performance, or both - owing to the sensitivity of synthetic conditions.

Role of NaCO as Nucleation Seeds to Accelerate the CO Uptake Kinetics of MgO-Based Sorbents.

There is an urgent need for inexpensive, functional materials that can capture and release CO under industrial conditions. In this context, MgO is a highly promising, earth-abundant CO sorbent. However, despite its favorable carbonation thermodynamics and potential for high gravimetric CO uptakes, MgO-based CO sorbents feature slow carbonation kinetics, limiting their CO uptake during typical industrial contact times.

Preserving High Porosity of Covalent Organic Frameworks via Functional Polymer Guest Introduction.

Due to their high structural tunability, remarkable internal surface areas, readily accessible pore space, and host of possible applications, covalent organic frameworks (COFs) remain at the forefront of materials science research. Unfortunately, many COFs suffer from structural distortions or pore collapse during activation, which can lead to a substantial loss of crystallinity and functionality. Thus, herein, we demonstrate a facile method to address this issue by introducing polymer guests.

A post-synthetic modification strategy for enhancing Pt adsorption efficiency in MOF/polymer composites.

Growing polymers inside porous metal-organic frameworks (MOFs) can allow incoming guests to access the backbone of otherwise non-porous polymers, boosting the number and/or strength of available adsorption sites inside the porous support. In the present work, we have devised a novel post-synthetic modification (PSM) strategy that allows one to graft metal-chelating functionality onto a polymer backbone while inside MOF pores, enhancing the material's ability to recover Pt(iv) from complex liquids. For this, polydopamine (PDA) was first grown inside of a MOF, known as Fe-BTC (or MIL-100 Fe).

How Reproducible is the Synthesis of Zr-Porphyrin Metal-Organic Frameworks? An Interlaboratory Study.

Metal-organic frameworks (MOFs) are a rapidly growing class of materials that offer great promise in various applications. However, the synthesis remains challenging: for example, a range of crystal structures can often be accessed from the same building blocks, which complicates the phase selectivity. Likewise, the high sensitivity to slight changes in synthesis conditions may cause reproducibility issues.

Rapid, Selective Extraction of Silver from Complex Water Matrices with a Metal-Organic Framework/Oligomer Composite Constructed via Supercritical CO.

Every year vast quantities of silver are lost in various waste streams; this, combined with its limited, diminishing supply and rising demand, makes silver recovery of increasing importance. Thus, herein, we report a controllable, green process to produce a host of highly porous metal-organic framework (MOF)/oligomer composites using supercritical carbon dioxide (ScCO ) as a medium. One resulting composite, referred to as MIL-127/Poly-o-phenylenediamine (PoPD), has an excellent Ag adsorption capacity, removal efficiency (>99 %) and provides rapid Ag extraction in as little as 5 min from complex liquid matrices.

Uranium(IV) and Thorium(IV) Coordination Polymers Based on Tritopic Carboxylic Acids.

Nine new coordination polymers based on U(IV) and Th(IV) were synthesized solvothermally utilizing four different trianionic carboxylates (HBHTC = biphenyl-3,4',5-tricarboxylic acid, HNTB = 4,4',4″-nitrilotribenzoic acid, HBTB = 4,4',4″-benzene-1,3,5-triyl-tris(benzoic acid), HBTE = 4,4',4″-(1,3,5-benzenetriyltri-2,1-ethynediyl)trisbenzoic acid). The influence of the ligand architecture, the pH, the stoichiometry, the nature of the metal, and the concentration on the structure and dimensionality of the final actinide assembly is discussed. The HBHTC ligand allowed the synthesis of a cationic three-dimensional (3D) framework [U(BHTC)(DMF)]I (), which is the first example of a cationic U(IV) polymer.

A customized MOF-polymer composite for rapid gold extraction from water matrices.

With the fast-growing accumulation of electronic waste and rising demand for rare metals, it is compelling to develop technologies that can promotionally recover targeted metals, like gold, from waste, a process referred to as urban mining. Thus, there is increasing interest in the design of materials to achieve rapid, selective gold capture while maintaining high adsorption capacity, especially in complex aqueous-based matrices. Here, a highly porous metal-organic framework (MOF)-polymer composite, BUT-33-poly(-phenylenediamine) (PpPD), is assessed for gold extraction from several matrices including river water, seawater, and leaching solutions from CPUs.

A Simple, Transition Metal Catalyst-Free Method for the Design of Complex Organic Building Blocks Used to Construct Porous Metal-Organic Frameworks.

The design of metal-organic frameworks (MOFs) having large pore sizes and volumes often requires the use of complex organic ligands, currently synthesized using costly and time-consuming palladium-catalyzed coupling chemistry. Thus, in the present work, a new strategy for ligand design is reported, where piperazine and dihydrophenazine units are used as substitutes for benzene rings, which are the basic building block of most MOF ligands. This chemistry, which is based on simple, nucleophilic aromatic substitution (S Ar) reactions, is used for the transition metal catalyst-free construction of 21 new, carboxylate-based ligands with varying sizes, shapes, and denticity and 15 linear di- and tetra-nitriles.

Solid-state synthesis of a MOF/polymer composite for hydrodeoxygenation of vanillin.

A new solid-state method was used to introduce a furan-thiourea polymer into the pores of a MOF, Cr-BDC. Next, the activity of the new MOF-polymer composite containing Pd was assessed in the catalytic hydrodeoxygenation of vanillin, a biomass derived chemical.

3D turbostratic: controlling metal-organic framework dimensionality -heterocyclic carbene chemistry.

Using azolium-based ligands for the construction of metal-organic frameworks (MOFs) is a viable strategy to immobilize catalytically active -heterocyclic carbenes (NHC) or NHC-derived species inside MOF pores. Thus, in the present work, a novel copper MOF referred to as Cu-Sp5-BF, is constructed using an imidazolinium ligand, HSp5-BF, 1,3-bis(4-carboxyphenyl)-4,5-dihydro-1-imidazole-3-ium tetrafluoroborate. The resulting framework, which offers large pore apertures, enables the post-synthetic modification of the C carbon on the ligand backbone with methoxide units.

Hybridization of Synthetic Humins with a Metal-Organic Framework for Precious Metal Recovery and Reuse.

The number of synthetic strategies used to functionalize MOFs with polymers is rapidly growing; this stems from the knowledge that non-native polymeric guests can significantly boost MOF performance in a number of desirable applications. The current work presents a scalable and solid-state method for MOF/polymer composite production. This simple method constitutes mixing a MOF powder, namely, Fe-BTC (BTC = 1,3,5-benzenetricarboxylate), with a biomass-derived solid monomer, 5-hydroxymethylfurfural (HMF), and subsequently heating the solids; the latter promotes both solid-state diffusion of HMF into the MOF and the formation of polymeric humin species with a high density of accessible hydroxyl functionality within the MOF pore.

A Two Step Postsynthetic Modification Strategy: Appending Short Chain Polyamines to Zn-NH-BDC MOF for Enhanced CO Adsorption.

Functionalizing metal-organic frameworks (MOFs) with amines is a commonly used strategy to enhance their performance in CO capture applications. As such, in this work, a two-step strategy to covalently functionalize NH-containing MOFs with short chain polyamines was developed. In the first step, the parent MOF, ZnO(NH-BDC), was exposed to bromoacetyl bromide (BrAcBr), which readily reacts with pendant -NH groups on the 2-amino-1,4-benzenedicarboxylate (NH-BDC) ligand.

Mechanistic Study on Thermally Induced Lattice Stiffening of ZIF-8.

The flexibility of the ZIF-8 aperture, which inhibits a molecular cutoff of 3.4 Å, can be reduced by rapid heat treatment to obtain CO-selective membranes. However, the early stages of the structural, morphological, and chemical changes responsible for the lattice rigidification remain elusive.

Understanding How Ligand Functionalization Influences CO and N Adsorption in a Sodalite Metal-Organic Framework.

In this work, a detailed study is conducted to understand how ligand substitution influences the CO and N adsorption properties of two highly crystalline sodalite metal-organic frameworks (MOFs) known as Cu-BTT (BTT = 1,3,5-benzenetristetrazolate) and Cu-BTTri (BTTri = 1,3,5-benzenetristriazolate). The enthalpy of adsorption and observed adsorption capacities at a given pressure are significantly lower for Cu-BTTri compared to its tetrazole counterpart, Cu-BTT. In situ X-ray and neutron diffraction, which allow visualization of the CO and N binding sites on the internal surface of Cu-BTTri, provide insights into understanding the subtle differences.

Preparation of Highly Porous Metal-Organic Framework Beads for Metal Extraction from Liquid Streams.

Metal-organic frameworks (MOFs) offer great promise in a variety of gas- and liquid-phase separations. However, the excellent performance on the lab scale hardly translates into pilot- or industrial-scale applications due to the microcrystalline nature of MOFs. Therefore, the structuring of MOFs into pellets or beads is a highly solicited and timely requirement.

Evaluation of materials for iodine and technetium immobilization through sorption and redox-driven processes.

Radioactive iodine-129 (I) and technetium-99 (Tc) pose a risk to groundwater due to their long half-lives, toxicity, and high environmental mobility. Based on literature reviewed in Moore et al. (2019) and Pearce et al.

Preserving Porosity of Mesoporous Metal-Organic Frameworks through the Introduction of Polymer Guests.

High internal surface areas, an asset that is highly sought after in material design, has brought metal-organic frameworks (MOFs) to the forefront of materials research. In fact, a major focus in the field is on creating innovative ways to maximize MOF surface areas. Despite this, large-pore MOFs, particularly those with mesopores, continue to face problems with pore collapse upon activation.

A new post-synthetic polymerization strategy makes metal-organic frameworks more stable.

Metal-organic frameworks are of interest in a number of host-guest applications. However, their weak coordination bonding often leads to instability in aqueous environments, particularly at extreme pH, and hence, is a challenging topic in the field. In this work, a two-step, post-synthetic polymerization method is used to create a series of highly hydrophobic, stable MOF composites.

An Neutron Diffraction and DFT Study of Hydrogen Adsorption in a Sodalite-Type Metal-Organic Framework, Cu-BTTri.

Herein we present a detailed study of the hydrogen adsorption properties of Cu-BTTri, a robust crystalline metal-organic framework containing open metal-coordination sites. Diffraction techniques, carried out on the activated framework, reveal a structure that is different from what was previously reported. Further, combining standard hydrogen adsorption measurements with neutron diffraction techniques provides molecular level insight into the hydrogen adsorption process.