Highly active palladium nanoparticles immobilized on NH2-MIL-125 as efficient and recyclable catalysts for Suzuki–Miyaura cross coupling reaction

Promoting Photocatalytic Activity of NH2-MIL-125(Ti) for H2 Evolution Reaction through Creation of TiIII- and CoI-Based Proton Reduction Sites

Titanium-based metal-organic framework, NH2-MIL-125(Ti), has been widely investigated for photocatalytic applications but has low activity in the hydrogen evolution reaction (HER). In this work, we show a one-step low-cost postmodification of NH2-MIL-125(Ti) via impregnation of Co(NO3)2. The resulting Co@NH2-MIL-125(Ti) with embedded single-site CoII species, confirmed by XPS and XAS measurements, shows enhanced activity under visible light exposure. The increased H2 production is likely triggered by the presence of active CoI transient sites detected upon collection of pump-flow-probe XANES spectra. Furthermore, both photocatalysts demonstrated a drastic increase in HER performance after consecutive reuse while maintaining their structural integrity and consistent H2 production. Via thorough characterization, we revealed two mechanisms for the formation of highly active proton reduction sites: nondestructive linker elimination resulting in coordinatively unsaturated Ti sites and restructuring of single CoII sites. Overall, this straightforward manner of confinement of CoII cocatalysts within NH2-MIL-125(Ti) offers a highly stable visible-light-responsive photocatalyst.

Modified hydrophobic and oleophilic polyurethane sponge for oil absorption with MIL-53

A hydrophobic composite sponge (HPCS) is developed for the first time using the dip coating and drying method in an effort to remove organic contaminants like toluene and various oils from water. We employed a polyurethane (PU) sponge, which is reasonably priced, easily accessible, high mechanical strength and a suitable porous substrate on which the hydrophobic composite of MIL-53(Al) along with PDMS was anchored. A crystalline metal organic framework (MOF), MIL-53(Al), with adjustable porosity, functionality, and hydrophobicity is used for oil absorption. Polydimethylsiloxane (PDMS) is utilized to increase the hydrophobicity of MIL-53(Al). The MIL-53(Al)@PDMS composite was used to the produce a sponge having high hydrophobicity and oleophilicity. In contrast to PU sponge, which has a low water contact angle (79.64°), the hydrophobic composite sponge showed a wide range of oil absorption capacity (12-50.5 g/g), a very low amount of water absorption (0.84 g/g), and water contact angle of 128.13°. This hydrophobic composite performed phenomenally by separating out various oils and solvents from water even in varying ionic strengths. Moreover, the recyclability of the formed composite was also performed resulting into 6-20 cycles for different oils and solvents. The synthesized hydrophobic composite sponge was characterized using FT-IR, XRD, TEM, surface area analysis, FESEM, XPS, TG analysis and contact angle measurement. Furthermore, the materials used in the synthesis of composite are non-toxic and do not harm the environment, resulting in no greenhouse gas emissions making our composite environmentally friendly.

Amino-functionalized NH2-MIL-125(Ti)-decorated hierarchical flowerlike Znln2S4 for boosted visible-light photocatalytic degradation

Developing novel heterojunction photocatalysts with visible-light response and remarkable photocatalytic activity have been verified to applying for the photodegradation of antibiotics in water environment. Herein, NH₂-MIL-125(Ti) was integrated with flowerlike ZnIn₂S₄ to construct NH₂-MIL-125(Ti)@ZnIn₂S₄ heterostructure using a one-pot solvothermal method. The photocatalytic performance was evaluated by the degradation of tetracycline (TC) under visible light illumination. The optimized NM(2%)@ZIS possesses a photodegradation rate (92.8%) and TOC removal efficiency (58.5%) superior to pristine components, which can be principally attributed to the positive cooperative effects of well-matched energy level positions, strong visible-light-harvesting capacity, and abundant coupling interfaces between the two. Moreover, the probable TC degradation mechanism was also clarified using the active species trapping experiments. This study inspires further design and construction of NH₂-MIL-125(Ti) and ZnIn₂S₄ based photocatalysts for effective removal of antibiotics in water environment.

The role of metal–organic porous frameworks in dual catalysis

Metal–organic frameworks (MOFs) are a valuable group of porous crystalline solids with inorganic and organic parts that can be used in dual catalysis.

An Au@NH2-MIL-125(Ti)-based multifunctional platform for colorimetric detections of biomolecules and Hg2+

Au@NH₂-MIL-125(Ti) was fabricated and explored as a multifunctional platform for sensitive colorimetric detections of biomolecules and Hg²⁺.

Metal Organic Frameworks as Robust Host of Palladium Nanoparticles in Heterogeneous Catalysis: Synthesis, Application, and Prospect

Metal organic frameworks (MOFs) are one set of the most excellent supports for Pd nanoparticles (NPs). MOFs as the host mainly have the following advantages: (i) they provide size limits for highly dispersed Pd NPs; (ii) fixing Pd NPs is beneficial for separation and reuse, avoiding the loss of expensive metals; (iii) the MOFs skeleton is diversified and functionalized, which is beneficial to enhancing the interaction with Pd NPs and prolonging the service life of the catalyst. This review discusses the synthesis strategy of Pd@MOF, which provides guidance for the synthesis of similar materials. After that, the research advance of Pd@MOF in heterogeneous catalysis is comprehensively summarized, including C-C coupling reaction, benzyl alcohol oxidation reaction, simple olefin hydrogenation reaction, nitroaromatic compound reduction, tandem reaction, and the photocatalysis, with the emphasis in providing a comparison with the performance of other alternative Pd-containing catalysts. In the final section, this review presents the current challenges and which are the next goals in this field.

The development of MOFs-based nanomaterials in heterogeneous organocatalysis

Metal-organic framework (MOF) is a class of inorganic-organic hybrid material assembled periodically with metal ions and organic ligands. MOFs have always been the focuses in a variety of frontier fields owing to the advantageous properties, such as large BET surface areas, tunable porosity and easy-functionalized surface structure. Among the various application areas, catalysis is one of the earliest application fields of MOFs-based materials and is one of the fastest-growing topics. In this review, the main roles of MOFs in heterogeneous organocatalysis have been systematically summarized, including used as support materials (or hosts), independent catalysts, and sacrificial templates. Moreover, the application prospects of MOFs in photocatalysis and electrocatalysis frontiers were also mentioned. Finally, the key issues that should be conquered in future were briefly sketched in the final parts of each item. We hope our perspectives could be beneficial for the readers to better understand these topics and issues, and could also provide a direction for the future exploration of some novel types of MOFs-based nanocatalysts with stable structures and functions for heterogeneous catalysis.

Photocatalytic production of hydrogen peroxide through selective two-electron reduction of dioxygen utilizing amine-functionalized MIL-125 deposited with nickel oxide nanoparticles

Photocatalytic H₂O₂ production via two-electron reduction of O₂ is realized by visible-light irradiation of a Ti-based metal–organic framework, MIL-125-NH₂.

Photo-Assisted Synthesis of a Pd-Ag@CQD Nanohybrid and Its Catalytic Efficiency in Promoting the Suzuki-Miyaura Cross-Coupling Reaction under Ligand-Free and Ambient Conditions

Supported bimetallic nanoparticles are very promising heterogeneous catalysts for carbon-carbon cross-coupling reactions, though reports focusing on their synergistic activity for promoting such reactions are very limited. In the current study, bimetallic Pd-Ag hybrid nanoparticles supported on carbon quantum dots (CQDs), Pd-Ag@CQDs, were synthesized by a facile and fast UV-light-driven (365 nm) one-pot protocol for the first time to investigate such a synergistic activity. The physico-chemical structural features of the Pd-Ag@CQD nanohybrid were evaluated by UV-vis, Fourier transform infrared, X-ray diffraction, electron-dispersive X-ray, and transmission electron microscopy analyses. The nanohybrid was found to have dimensions in the range of ca. 3-5 nm. The bimetallic Pd-Ag@CQD nanohybrid was utilized as an efficient heterogeneous catalyst for promoting the Suzuki-Miyaura coupling reaction with aryl bromides and aryl chlorides under ligand-free and ambient conditions. The synergistic activity of the components of the nanohybrid induced catalytic enhancement of the cross-coupling reaction in terms of short reaction times (<1 h) and high yields (>90%). The heterogeneous character of the nanohybrid system also enabled easy separation and recyclability (up to six cycles).

Solvent-free and melt aerobic oxidation of benzyl alcohols using Pd/Cu2(BDC)2DABCO–MOF prepared by one-step and through reduction by dimethylformamide

In this paper we report an efficient method for the aerobic oxidation of benzyl alcohols to aldehydes by supported palladium nanoparticles in nanoporous metal–organic framework Cu₂(BDC)₂(DABCO) that Pd(ii) in MOF reduced without using any external reducing agent.

Palladium nanoparticles supported on a nickel pyrazolate metal organic framework as a catalyst for Suzuki and carbonylative Suzuki couplings

Methanolic reduction of [PdCl₂(CH₃CN)₂] on a [Ni(2,5-di(1H-pyrazol-4-yl)benzenesulfonate)₂] metal organic framework gives rise to Pd²⁺/Pd⁰ nanocomposites with Suzuki and carbonylative Suzuki heterogeneous catalytic activities.

Immobilization of a thiol-functionalized ionic liquid onto HKUST-1 through thiol compounds as the chemical bridge

The IL@HKUST-1 catalyst was synthesized by a post-synthetic modification strategy. The introduction of ionic liquid greatly improved the acidity of the material, making it an efficient and recyclable catalyst for the esterification reaction.