Active Heterogeneous Catalyst Research Articles

Efficient degradation of Enrofloxacin with novel magnetic MnFe2O4/NiS2 composite as an activator of peroxymonosulfate

The development of highly active and recoverable heterogeneous catalysts for peroxymonosulfate (PMS) activation to remove the persistent presence of antibiotics in aquatic environments, such as Enrofloxacin (ENR), remains a significant challenge. Here, we introduce a pioneering magnetic nanocomposite catalyst, MnFe2O4-NiS2, synthesized via a two-step hydrothermal process, which activates PMS to efficiently degrade ENR. The optimized 0.25MnFe2O4-NiS2/PMS system reached an ENR removal efficiency of 89.9 % within 90 min, outperforming both NiS2/PMS and MnFe2O4/PMS by 5.6 and 2.5 times, respectively. Quenching experiments and electron spin response analysis confirmed SO4•- and •O2– as the primary reactive oxygen species. The enhanced mediated electron transfer capability of the 0.25MnFe2O4-NiS2 nanocomposite improved the redox cycling of Ni (Ⅱ), Mn (Ⅱ) and Fe (Ⅲ) on its surface, as verified by Density Functional Theory calculations. Furthermore, the activation of surface PMS complexes (PMS*) played a crucial role in ENR degradation. The proposed degradation pathways of ENR were confirmed, and toxicity analysis indicated a decrease in intermediate toxicity with the 0.25MnFe2O4-NiS2/PMS system. This study presents an innovative magnetically recoverable, multifunctional catalyst with easy reusability for potential applications in the degradation of organic pollutants.

Research Progress on Catalytic Ceramic Membrane Degradation of Phenol Containing Wastewater

In recent years, ceramic membrane supported catalysts for catalytic ozonation have made certain progress in the treatment of organic wastewater. This process has the advantages of simple operation, high oxidation efficiency, high catalyst utilization, ceramic membrane resistance to pollution, and no secondary pollution. However, the large-scale promotion and use of this process still rely on the development of highly active and stable heterogeneous catalysts. Therefore, it is crucial to summarize the development status of ceramic membrane supported ozone catalysts at home and abroad in recent years. This article first summarizes the recent research on catalytic membranes; Secondly, the production method of catalytic ceramic membrane is elaborated; Finally, the research significance of catalytic ceramic membranes is discussed.

Microwave and ultrasound-assisted green protocols for 5-methylthiazole induced Betti bases: molecular docking, in-silico pharmacokinetics, and anticancer activity studies

ABSTRACT Herein, we describe an efficient one-pot three-component microwave and ultrasound-endorsed approaches for synthesizing distinct 5-methylthiazole induced Betti bases (5-methyl-thiazol-2-ylamino-aryl-benzylnapthols) employing silica sulfuric acid (SSA, silica-OSO3H) as an active heterogeneous acid catalyst. The title compounds produced in good yields (86–95%) from naphthalen-2-ol, 5-methylthiazol-2-amine, and assorted aryl aldehydes; and structurally characterized by spectral and elemental analyses. A comprehensive comparative study of conventional, ultrasonic, and microwave-irradiated synthetic routes has been achieved by optimizing various reaction parameters. These new protocols provide several advantages, including the use of an inexpensive, non-toxic, and reusable catalyst. Additionally, they benefit from mild reaction conditions, short reaction times, and simple workup and purification procedures, thereby increasing their practicality. Furthermore, the synthesized compounds were evaluated for their anticancer potency against A-549 (lung cancer) and A-498 (kidney cancer) cell lines, with scaffold IVa demonstrating excellent (GI50 < 10 µg/mL) inhibitory activity against A-549. Additionally, molecular docking was performed to investigate potential binding interactions between ligands and proteins. Scaffold IVa exhibited the best docking with cancerous target proteins 1M17 (−8.9 kcal/mol) and 1M14 (−7.2 kcal/mol), thereby supporting our bio-activity studies.

Improvement of heterogeneous electro-Fenton oxidation of dimethyl phthalate by embedding Fe/Co bimetallic active sites into waste wine lees biochar

Phthalates (PAEs) are frequently detected in the water environment and pose a severe threat to the ecosystem and human health. Electro-Fenton technology is regarded as an effective approach to degrade PAEs; however, the preparation of inexpensive and efficient cathode materials has restricted its further application. In this study, Fe/Co bimetallic sites were incorporated into solid waste wine lees to synthesize highly active heterogeneous catalyst, and dimethyl phthalate (DMP) was chosen as the target pollutant to investigate the activity of the catalyst. Both the degradation of DMP and the removal of total organic carbon (TOC), the performance of Fe/Co co-modified biochar (FeCo@NOPC) is superior to that of Fe (Co) alone (Fe@NOPC/Co@NOPC) and modified biochar (NOPC). Under neutral conditions. Within 5 h, the DMP removal rate reached 89 % and TOC was reduced by approximately 40 %. The mechanism study reveals that the degradation of DMP is mainly attributed to the OH generated by the cathode, and the anodic oxidation and cathode adsorption only play minor roles. Finally, the degradation path of DMP was analyzed by LC-MS technique. This study offers a novel way to utilize solid waste and reduce the cost of heterogeneous electro-Fenton system.

In-situ activation of biomimetic single-site bioorthogonal nanozyme for tumor-specific combination therapy

Copper-catalyzed click chemistry offers creative strategies for activation of therapeutics without disrupting biological processes. Despite tremendous efforts, current copper catalysts face fundamental challenges in achieving high efficiency, atom economy, and tissue-specific selectivity. Herein, we develop a facile “mix-and-match synthetic strategy” to fabricate a biomimetic single-site copper-bipyridine-based cerium metal-organic framework (Cu/Ce-MOF@M) for efficient and tumor cell-specific bioorthogonal catalysis. This elegant methodology achieves isolated single-Cu-site within the MOF architecture, resulting in exceptionally high catalytic performance. Cu/Ce-MOF@M favors a 32.1-fold higher catalytic activity than the widely used MOF-supported copper nanoparticles at single-particle level, as first evidenced by single-molecule fluorescence microscopy. Furthermore, with cancer cell-membrane camouflage, Cu/Ce-MOF@M demonstrates preferential tropism for its parent cells. Simultaneously, the single-site CuII species within Cu/Ce-MOF@M are reduced by upregulated glutathione in cancerous cells to CuI for catalyzing the click reaction, enabling homotypic cancer cell-activated in situ drug synthesis. Additionally, Cu/Ce-MOF@M exhibits oxidase and peroxidase mimicking activities, further enhancing catalytic cancer therapy. This study guides the reasonable design of highly active heterogeneous transition-metal catalysts for targeted bioorthogonal reactions.

Palladium supported on alumina as a highly active heterogeneous catalyst for direct arylation of 6-substituted imidazo[2,1-b]thiadiazole via C[sbnd]H bond activation reaction

Fast, atom-economical, phosphine-free, and eco-friendly microwave-irradiated reactions permitting the “green synthesis” of 5,6-disubstituted imidazo[2,1-b]thiadiazole derivatives using heterogeneous palladium catalyst in triethylammonium 2-(1,1-dioxido-3-oxobenzo[d]isothiazol-2(3H)-yl)acetate ([Et3NH][Sac-CH3CO2]) ionic liquid via CH bond activation reaction of 6-substituted imidazo[2,1-b]thiadiazole derivatives, are reported. This method provides a straightforward route to a wide variety of substituted imidazo[2,1-b]thiadiazoles and has the advantages of reusability of the heterogeneous catalyst, simple methodology, high yields, and easy work-up.

Ultrasmall Pd nanoparticles supported on a metal–organic framework DUT-67-PZDC for enhanced formic acid dehydrogenation

The highly dispersed ultrasmall palladium nanoparticles (Pd NPs) (1.7 nm) were successfully immobilized on a N-containing metal–organic framework (MOF, DUT-67-PZDC) using a co-reduction method, and it is used as an excellent catalyst for formic acid dehydrogenation (FAD). The optimized catalyst Pd/DUT-67-PZDC(10, 10 wt% Pd loading) shows 100% hydrogen (H2) selectivity and formic acid (FA) conversion at 60 °C, and the commendable initial turnover frequency (TOF) values of 2572 h−1 with the sodium formate (SF) as an additive and 1059 h−1 even without SF, which is better than most reported MOF supported Pd monometallic heterogeneous catalysts. The activation energy (Ea) of FAD is 43.2 KJ/mol, which is lower than most heterogeneous catalysts. In addition, the optimized catalyst Pd/DUT-67-PZDC(10) maintained good stability over five consecutive runs, demonstrating only minimal decline in catalytic activity. The outstanding catalytic performance could be ascribed to the synergistic corporations of the unique structure of DUT-67-PZDC carrier with hierarchical pore characteristic, the metal-support interaction (MSI) between the active Pd NPs and DUT-67-PZDC, the highly dispersed Pd NPs with ultrafine size serve as the catalytic active site, as well as the N sites on the support could act as the proton buffers. This work provides a new paradigm for the efficient H2 production of FAD by constructing highly active heterogeneous Pd-based catalysts using MOF supports.

Highly Efficient Low-loaded PdOx/AlSiOx Catalyst for Ethylene Dimerization.

Ethylene dimerization is an industrial process that is currently carried out using homogeneous catalysts. Here we present a highly active heterogeneous catalyst containing minute amounts of atomically dispersed Pd. It requires no co-catalyst(s) or activator(s) and significantly outperforms previously reported catalysts tested under similar reaction conditions. The selectivity to C4- and C6-hydrocarbons was about 80 % and 10 % at 42 % ethylene conversion at 200 °C using an industrially relevant feed containing 50 vol % ethylene, respectively. Our kinetic and catalyst characterization experiments complemented by density functional theory calculations provide molecular insights into the local environment of isolated Pd(II)Ox species and their role in achieving high activity in the target reaction. When the developed catalyst was rationally integrated with a Mo-containing olefin metathesis catalyst in the same reactor, the formed butenes reacted with ethylene to propylene with a selectivity of 98 % at about 24 % ethylene conversion.

Reductive N-Alkylation of Amines with Ketones Using Heterogeneous Polysilane-Palladium Catalysts under Continuous-Flow Conditions.

This work reports a continuous-flow reductive N-alkylation of amines with ketones using molecular hydrogen. The reaction, performed with highly active polysilane-modified heterogeneous palladium catalysts, enables the efficient synthesis of diversely substituted amines under mild flow conditions. The developed catalyst exhibits sustained activity for 5 days (turnover number of >2400). Moreover, the utility of the method is demonstrated by the synthesis of a key intermediate of the active pharmaceutical ingredient teneligliptin.

Modified nano magnetic Fe2O3-MgO as a high active multifunctional heterogeneous catalyst for environmentally beneficial carbon–carbon synthesis

In this study, novel nanomagnetic catalysts, namely Fe2O3-MgO@choline formate (Ch. F.) and Fe2O3-MgO@choline cyanide (Ch. CN), were synthesized through immobilizing choline-based ion liquids to magnetic support via a simple and cost-effective methodology. FT-IR, TGA, FE-SEM, VSM, EDS, BET, and XRD techniques were employed to assess and characterize these organic–inorganic compounds. Following the successful preparation of nanoparticles, the catalysts were utilized in Knoevenagel and benzoin condensations. Fe2O3-MgO@Ch.F. exhibited exceptional activity in Knoevenagel condensation under solvent-free conditions at room temperature, achieving high yields (91–98%) in a short timeframe. Similarly, Fe2O3-MgO@Ch.CN demonstrated remarkable activity in benzoin condensation under environmentally friendly solvent conditions, yielding higher isolated yields (76–88%). Furthermore, these magnetically recyclable multifunctional catalysts displayed the ability to be reused up to five times without a significant loss in efficiency. Additionally, the heterogeneity of this nanocatalyst was investigated using the hot filtration technique. The findings indicated that the reaction primarily occurs via a heterogeneous pathway.

Feasible preparation of preferentially oriented (111) Pd nanocrystals supported on cyano-COFs for ultrahigh activity in C-C cross-couplings

It is much challenging to synthesize highly dispersed noble metal nanocrystals (MNCs) and prevent their aggregation during the catalytic cycles. Choosing suitable solid supports to mediate the growth of MNCs can provide stable yet ultra-highly active heterogenous catalysts. However, very few studies have provided the controllable preparation of ultrafine MNCs. Herein, cyano-functionalized covalent organic frameworks (cyano-COFs)-mediated ultrafine preferentially oriented (111) PdNCs with particle diameter of 2.88 ± 0.60 nm were easily prepared in MeOH without any other external reducing agent. The obtained Pd/cyano-COFs presented ultrahigh activity in Suzuki-Miyaura couplings, with TOF of 2578 h−1 and chemo-selectivity of > 99 % for the cross-coupling between p-iodotoluene and phenylboronic acid at room temperature in the air. Furthermore, outstanding catalytic performance of Pd/cyano-COFs was found in Heck couplings as well. This study provides a new idea for the controllable preparation of metallic nanomaterials with high performance, which could facilitate the research on the regulation of catalytic performance by the chemical composition of supports.

Bimetallic FeCo nanoparticles embedded N-rich porous ZIF-derived carbon as highly active heterogeneous Fenton catalyst for degradation of tetracycline and organic dyes

Peroxymonosulfate (PMS) based advanced oxidation process (AOP) is used for the degradation of the organic molecules due to ease of reactive oxygen species (ROS) generation through activation. In this study, bimetallic FeCo nanoparticles (NPs) supported on N-doped porous carbons are prepared for the first time by in-situ co-precipitation of metal ions in ZIF-67 followed by carbonization. The prepared nanocomposite, denoted as Fe(x)Co@N-CZ-67, is used to activate PMS for Fenton-like degradations of tetracycline (TC) and dyes. The results reveal that about 96% of TC is degraded by Fe(0.4)Co@N-CZ-67 in 4 min. The catalyst can also degrade three organic dyes, namely methylene blue, neutral red and methyl orange with outstanding reaction rates of 1.75, 1.80 and 2.62 min−1, respectively. The excellent catalytic activities of the catalysts can be ascribed to the synergistic effects between Fe and Co that enhance the electron transfer rate, uniform dispersion of NPs, presence of N in support, and generation of surface PMS complexes with high oxidation activity. Based on the quench experiments, SO4•–, •OH, O2•− and 1O2 are determined to be the ROS responsible for degradations organic molecules. Fe(x)Co@N-CZ-67 shows excellent catalytic activity over ten consecutive cycles with negligible metal leaching and remarkable structural stability.

Preparation and characterization of biomimetic heterogeneous catalysts with Cu(II) and Mn(III) complexes

New catalysts were synthesized by immobilization of Cu(II) and Mn(III) biomimetic complexes onto mesoporous SBA-15 silica, amino-functionalized SBA-15, montmorillonite and Al-pillared montmorillonite supports. [Cu(acac)(phen)(OH2)](ClO4) and [Cu(acac)(Me2bipy)](ClO4) copper complexes and [Mn(III)(valen)(H2O)(CH3CN)](ClO4)∙CH3CN manganese complex supported on silica pore surface or intercalated into the interlayer spaces of clays, were characterized by X-ray diffraction, N2 adsorption-desorption, TGA-DTA analysis, IR and UV-Vis spectroscopy. These results have confirmed the structural stability of the mesoporous hosts and successful anchoring of the metal complexes over the supports. In order to verify the biomimetic comportment, catalytic activities of the free and immobilized complexes and that of Trametes versicolor laccase, immobilized on the same supports, were tested by oxidation with air of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), the most used substrate for estimation of specific activity of laccases. The supported complexes were more active than the free ones. Furthermore, the stability tests for the most active heterogeneous catalyst confirmed that the best support was NH2-SBA-15.

MOF‐Supported Heterogeneous Catalysts for Hydroformylation Reactions: A Minireview

AbstractTransition metal‐catalyzed hydroformylation reaction of olefins is one of the most important transformations in the perspective of both industrial applications and academic research. This synthetic process provides a straightforward and easy way for the transformations of inexpensive feedstock (mostly different alkene molecules) to valuable aldehyde compounds, which are considered as major building blocks for several essential chemical products. Inspired and motivated by the tremendous success of homogeneous catalysis for hydroformylation reactions, paramount interests have been raised for the design and development of active heterogeneous catalysts owning advantages from both molecular and material sciences. Crystalline metal‐organic frameworks (MOFs) as solid support to immobilize active catalysts for the hydroformylation reaction have shown appealing promises as heterogeneous catalysts. This review sketches out a decade of developments of MOF‐based heterogeneous catalysts for the hydroformylation of olefins while discussing both advantages and limitations for their implementation beyond the lab scale.

Chemical activation of atom-precise Pd3 nanoclusters on γ-Al2O3 supports for transfer hydrogenation reactions.

Deposition of atom-precise nanoclusters onto solid supports is a promising route to synthesize model heterogeneous catalysts. However, to enhance nanocluster-support interactions, activation of the nanoclusters by removal of surface ligands is necessary. Thermal treatment to remove surface ligands from supported metal nanoclusters can yield highly active heterogeneous catalysts, however, the high temperatures employed can lead to poor control over the final size and speciation of the nanoclusters. As an alternative to high-temperature thermal treatments, chemical activation of [Pd3(μ-Cl)(μ-PPh2)2(PPh3)3]+ (Pd3) nanoclusters on γ-Al2O3 supports under mild reaction conditions has been demonstrated in this work. Hydride-based reducing agents such as NaBH4, LiBH4, and LiAlH4 have been examined for the activation of the Pd3 nanoclusters. The structural evolution and speciation of the nanoclusters after activation have been monitored using a combination of XAS, XPS, STEM-EDX mapping, and solid-state NMR techniques. The results indicate that treatment with borohydride reducing agents successfully removed surface phosphine and chloride ligands, and the extent of size growth of the nanoclusters during activation is directly correlated with the amount of borohydride used. Borate side products remain on the γ-Al2O3 surface after activation; moreover, exposure to high amounts of NaBH4 resulted in the incorporation of B atoms inside the lattice of the activated Pd nanoclusters. LiAlH4 treatment, on the other hand, led to no significant size growth of the nanoclusters and resulted in a mixture of Pd single-atom sites and activated nanoclusters on the γ-Al2O3 surface. Finally, the catalytic potential of the activated nanoclusters has been tested in the transfer hydrogenation of trans-cinnamaldehyde, using sodium formate/formic acid as the hydrogen donor. The catalytic results showed that smaller Pd nanoclusters are much more selective for hydrogenating trans-cinnamaldehyde to hydrocinnamaldehyde, but overall have lower activity compared to larger Pd nanoparticles. Overall, this study showcases chemical activation routes as an alternative to traditional thermal activation routes for activating supported nanoclusters by offering improved speciation and size control.

CoFe2O4/WS2 as a highly active heterogeneous catalyst for the efficient degradation of sulfathiazole by activation of peroxymonosulfate

In this study, MFe2O4/WS2 (M = Co, Cu, Mn, Ni) catalysts were synthesized to activate peroxymonosulfate (PMS) for sulfathiazole (STZ) degradation by decorating with WS2 on the surface of a series of spinel-type transition metal oxides. It was found that the CoFe2O4/WS2/PMS exhibited a greater ability to degrade sulfathiazole (STZ) than other systems. More specifically, the catalyst facilitated Fe3+/Fe2+ recycling to activate PMS efficiently and maintained synergies between CoFe2O4 and WS2 to degrade pollutants. The CoFe2O4/WS2 dosage, PMS concentration, solution pH, inorganic anions, and natural organic matter, which could affect the catalytic efficiency, were inspected. The experimental results manifested that the catalyst displayed outstanding performance in the pH range from 5 to 9. Besides, electron paramagnetic resonance spectroscopy and radical quenching experiments confirmed the presence of HO•, SO4•−, O2•−, and 1O2. Based on detected intermediates, the plausible degradation pathway of STZ was proposed.

Ruthenium-Picolylamine-Incorporated Mixed-Linker MOFs: Highly Active Heterogeneous Catalysts for Olefin and Aldehyde Hydrogenation

Ruthenium-Picolylamine-Incorporated Mixed-Linker MOFs: Highly Active Heterogeneous Catalysts for Olefin and Aldehyde Hydrogenation

КАТАЛИЗ ГИДРИРОВАНИЯ АРОМАТИЧЕСКИХ СОЕДИНЕНИЙ: ИСТОРИЯ И СОВРЕМЕННОЕ СОСТОЯНИЕ. ЧАСТЬ 2. ГИДРИРОВАНИЕ ПОЛИЯДЕРНЫХ АРОМАТИЧЕСКИХ УГЛЕВОДОРОДОВ, АЗОТ- И КИСЛОРОДЗАМЕЩЕННЫХ АРЕНОВ

The review is devoted to hydrogenation processes of aromatic substrates differing in reactivity using catalysts of different activity. The global trend in this area is the search for more active and selective heterogeneous catalysts for hydrogenation of the aromatic ring, both for industrial processes and in laboratory practice. An analysis of literature data on the hydrogenation of polynuclear aromatic hydrocarbons, phenol, aniline and their derivatives, as well as arenes substituted with a functional group, is presented. Various types of catalysts for the hydrogenation of an aromatic ring, the patterns of the process depending on the structure of the substrate and reaction conditions, the nature of the active phase and the catalyst support are considered.

Accessing 2‐Aryl Quinolines via Acceptorless Dehydrogenation and Transfer Hydrogenation Under Base and Solvent‐Free Reaction Conditions

AbstractCatalytic hydrogenation/dehydrogenation reactions are one of the most active areas of research for the synthesis of pharmaceuticals and fine chemicals. Despite several efficient homogeneous catalysts that have already been identified, highly active heterogeneous catalysts remain elusive. Herein, we report an easy and convenient wet impregnation method for the synthesis of Pd‐nanoclusters supported on ZnO nanoparticles. The catalyst displays a multifunctional role in 2‐aryl quinolines synthesis using alcohol and 2‐nitrobenzyl alcohol as reactants via dehydrogenation/hydrogenation pathway under neat and base‐free reaction conditions. The catalyst exhibits excellent selectivity and can be recycled five times without appreciable loss in its activity.

One-pot synthesis of ligand-free highly active Pd catalyst supported on NiFe spinel oxide for Suzuki–Miyaura cross-coupling reaction

This work underscores the development of an easily separable, very simple yet highly active heterogeneous Pd catalyst supported on Ni−Fe spinel oxide containing a low percentage of noble metal Pd (only 1 at.%) enabling the access to an advanced set of catalysts for Suzuki–Miyaura carbon–carbon (C−C) cross-coupling reaction that are not easily accessible with homogeneous catalysts. A series of catalytic experiments have revealed optimum reaction conditions for C−C coupling between aryl bromide and phenyl boronic acid. Among a set of prepared catalysts, NiPdFe-1 (Ni/Pd molar ratio=1:1) is found to be the most active catalyst for the coupling reaction completing in just about 30 min under mild reaction conditions like 100 °C using Na2CO3 as the base in a very common organic solvent, DMF. Interaction between the oxide support and Pd(0) makes the Pd surface more electron-rich which accelerates the rate-determining step of the C−C coupling reaction by faster electron transfer from Pd(0) to the aryl halides. Moreover, the catalyst is essentially heterogeneous, stable, magnetically separable and durable for several cycles without losing its activity. Good to excellent isolated yields have been obtained with a variety of functionalities on both the aryl bromide and phenyl boronic acid with varying electronic properties.