Catalyst For Synthesis Research Articles

Designing Sustainable Copper‐Based Hybrid Framework Catalysts for One‐Pot Multicomponent Organic Reactions

AbstractThe recent breakthroughs in heterogeneous catalysis emphasize the need for novel materials capable of driving organic transformations. The present study explores two copper phosphonate hybrid framework materials, 2D Cu3[(Hhedp)2(C4H4N2)].2H2O (Cu(II)Pyz‐P) and 3D Cu3[(H3hedp)2(C4H4N2)4(SO4)].2H2O (Cu(I/II)Pyz‐P), as single crystals isolated via hydrothermal synthetic strategy using H4hedp (1‐hydroxyethane 1,1‐diphosphonic acid) and N‐donor secondary ligand (Pyrazine; C4H4N2). Cu(II)Pyz‐P contains exclusively +2 oxidation state of copper, while Cu(I/II)Pyz‐P is characterized by a mixed oxidation state, where copper +2 phosphonate is embedded within the network formed by copper +1 state. Moreover, magnetic study elucidates the distinct oxidation states of both compounds by showing deviations from each other. The aforementioned compounds are exceedingly effective for catalyzing multicomponent reactions, that is, A3 coupling reaction and click reaction. Cu(I/II)Pyz‐P ensures the regioselective synthesis of triazole with high purity, while A3 coupling reaction is facilitated by both the compounds. Solvent‐ and additive‐free efficient multicomponent reactions are explored for the first time in the copper phosphonate hybrid framework structures. The present study reveals the promise of copper‐based hybrid phosphonate frameworks as durable and efficient catalysts for organic synthesis, providing cost‐effective and sustainable ways for advanced catalytic transformations.

Synergistic Effects of Cerium and Strontium Promoters on Copper‐Modified Iron‐Based Fischer–Tropsch Synthesis Catalysts

Synergistic Effects of Cerium and Strontium Promoters on Copper‐Modified Iron‐Based Fischer–Tropsch Synthesis Catalysts

Highly Efficient and Selective Electrocatalytic Semihydrogenation of Acetylene to Ethylene via Continuous Proton Feeding and Accelerated Transfer on Cu NP/FeNC Composite

AbstractElectrocatalytic hydrogenation of acetylene to ethylene in aqueous electrolytes under ambient conditions faces efficiency and selectivity limitation due to the competitive formation of 1,3‐butadiene and hydrogen. In this study, the development of a copper nanoparticle/FeNC composite catalyst is reported through a simple mechanical grinding approach that demonstrates remarkable performance, achieving a highest ethylene Faradaic efficiency of 97.7% at 180 mA cm−2 and selectivity of 92.6% at 200 mA cm−2. Experimental investigations reveal that Cu atoms serve as the active sites, and the integration of FeNC improves the specific surface area through its 2D nanosheet morphology. Further analysis utilizing in situ Raman measurements coupled with theoretical calculations confirms that FeNC accelerates water dissociation to provide abundant protons and improving their transfer, thereby suppressing 1,3‐butadiene formation and elevating acetylene selectivity. Notably, the integration of FeNC also transforms the desorption of *C2H4 into an exothermic process, further facilitating ethylene production. Overall, this study introduces a simple and innovative preparation approach of composite catalysts for selective ethylene synthesis, expanding the application scope of Cu‐based FeNC materials in various electrocatalytic hydrogenation reactions.

Single-Site Pd Regulated by π-π Stacking for High-Selectivity Cyclopropanation Reaction.

Cyclopropane-based high-energy fuels possess high intramolecular energy and density, and their precise synthesis is a critical challenge. However, owing to the highest strain in the cyclopropane structure (compared to other four- or five-membered rings, etc.), metal-carbene intermediates form with difficulty, resulting in poor catalytic selectivity for its synthesis. Herein, through rational design of π-π stacking between the Pd organic complex and graphene, we report a single-site Pd catalyst for precise synthesis of multicyclopropane-based high-energy fuels. It is discovered that π-π stacking enhanced the electrophilicity of Pd through a weak metal-support interaction, thus promoting the formation of Pd═C carbene active intermediates. Meanwhile, the adsorption between the active centers and intermediates was enhanced via π-π stacking. These two respects led to almost twice selectivity for cyclopropanation reaction up to 80.5% as that without π-π stacking. This work provides an effective strategy of π-π noncovalent interactions for regulating C-C coupling reaction selectivity.

Sodium Copper Chlorophyllin: A Sustainable Bioinspired Catalyst for the Aerobic Oxidative Synthesis of Nitrogen Heterocycles and the Oxidative Cyanation of Tertiary Amines

AbstractA remarkably simple and straightforward protocol has been reported showcasing sodium copper chlorophyllin (SCC) as an eco‐friendly, bioinspired catalyst for the aerobic oxidative synthesis of pharmaceutically prevalent nitrogen‐containing heterocycles, such as benzimidazoles and quinoxalines. This reaction was performed in green solvent water, using the green oxidant, molecular oxygen. SCC displayed exceptional efficiency, congruent with the prevailing metal/non‐metal‐based catalyst regime without requiring additives. The SCC catalyst exhibited excellent recyclability upto three cycles for the benzimidazole synthesis reaction. This benign strategy was successfully applied in synthesizing a bioactive quinoxaline i. e., Tyrphostin AG1296, a promising candidate for melanoma treatment. The catalytic activity of SCC was explored for the synthesis of another privileged moiety i. e., α‐aminonitriles, via the α‐cyanation of tertiary amines under oxidative conditions. This reaction progressed with a mild, easy‐to‐use, convenient cyanide source, such as ethyl cyanoformate, and a green and attractive solvent, such as methanol, precluding acidic media. SCC catalyst was efficiently recycled upto three cycles for the α‐aminonitriles synthesis. Overall, the utility of a biodegradable, robust catalyst such as SCC, eco‐friendly solvents such as water and methanol, green oxidants such as O2, and mild reaction conditions, devoid of acidic additives, renders the present work viable for academic and industrial research.

Liquid metal catalyst for ammonia synthesis at low pressure

Liquid metal catalyst for ammonia synthesis at low pressure

The Impact of Milling Energy on the Structure of Catalysts during the Mechanochemical Synthesis of Single-Atom Catalysts

The Impact of Milling Energy on the Structure of Catalysts during the Mechanochemical Synthesis of Single-Atom Catalysts

Scalable synthesis of Robust, high-loading nitrogen-infused intermetallic FePt@Pt (core@shell) catalyst for proton exchange membrane fuel cells

In this study, we propose PtFeIMN@Pt/C, featuring a Pt shell on a nitrogen-infused PtFe intermetallic core structure, and attempt large-scale synthesis of catalysts with high metal content (>50 wt%). Using the ultrasound-assisted polyol synthesis method, we synthesize core@shell structured PtFe@Pt/C catalysts with approximately 60 wt% metal content at a 10 g scale in a single step. Post-treatments, including annealing, acid treatment, and nitriding in high-pressure NH3 gas, follow to synthesize the target catalysts. Optimizing the annealing temperature reveals a trade-off relationship affecting catalyst activity and durability. The PtFeIMN@Pt/C_600 °C, synthesized under optimized conditions, exhibits superior electrochemical performance and durability compared to commercial Pt/C catalysts. The accelerated stability test (AST) further shows significantly enhanced durability when nitrogen is included in the core. In the single cell tests, PtFeIMN@Pt/C_600 °C demonstrates approximately four times higher mass activity than commercial Pt/C catalysts and a 29.9 mV voltage drop at 0.8 A cm−2 after AST, meeting the U.S. Department of Energy's targets.

Revolutionizing acridine synthesis: novel core-shell magnetic nanoparticles and Co-Zn zeolitic imidazolate framework with 1-aza-18-crown-6-ether-Ni catalysts

Nanoparticles have emerged as a critical catalyst substrate due to their exceptional features, such as catalytic efficiency, high stability, and easy recovery. In our research, we have developed an innovative and environmentally friendly magnetic mesoporous nanocatalyst. Using the co-precipitation method, we produced magnetic nanoparticles (Fe3O4) and coated them with Zeolitic imidazolate frameworks (ZIFs) to enhance their surface area and chemical stability. The resulting substrate was functionalized with 1-aza-18-crown-6-ether and nickel metal. Our prepared catalyst has been rigorously evaluated using advanced techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmet-Teller (BET), vibrating sample magnetometry (VSM), scanning electron microscopy and energy dispersive X-ray (SEM-EDS), inductively coupled plasma (ICP), elemental mapping analysis (EMA), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM). By synthesizing acridine derivatives, we have demonstrated the exceptional efficiency of our catalyst in organic compound synthesis. Through optimization, we have established the ideal parameters for catalytic processes, including catalyst amount, temperature, time, and ultrasonic use. Our catalyst has been proven to exhibit remarkable physical and chemical properties, such as porosity, temperature resistance, and recyclability. Notably, our heterogeneous nanocatalyst has shown outstanding performance and can be recycled six times without any loss in efficiency, affirming its potential in acridine.

MgCo2O4@g‐C3N4 Composite Induced Peroxymonosulfate Activation for Effective Degradation of Tetracycline Under Visible Light

AbstractThe composite Fenton catalyst was prepared by attaching MgCo2O4 to the surface of g‐C3N4 using a one‐pot method after preparing MgCo2O4 through co‐precipitation. The microstructure of the composites was analyzed using X‐ray diffraction (XRD) and other characterization methods. The catalytic activity of the composites towards tetracycline (TC) was studied, and a possible catalytic mechanism was proposed. The experimental results indicate that the degradation of TC by MgCo2O4@g‐C3N4 reached almost 99.0 % within 30 min in the presence of PMS and visible light. The combination of MgCo2O4 and g‐C3N4 improved the absorption of visible light, and the energy level‐matched heterojunction facilitated the separation of photogenerated electrons and holes, accelerating the redox cycle of ≡Co3+/≡Co2+. The free radical quenching experiment confirmed that the main active substances were free radical ⋅O2− and 1O2. The one‐step synthesis of composite catalysts exhibits high catalytic performance and good stability, offering a potential solution for the efficient treatment of tetracycline wastewater.

Heterogeneous Asymmetric Hydrogenation of C=C and C=O Double Bonds

Nowadays, heterogeneous catalysts play a crucial role in the field of asymmetric catalysis to produce enantiopure compounds for various applications. The unique properties of heterogeneous systems, such as high stability, reusability, or ease of separation, allow effective catalysis of asymmetric transformations and their further implementation in industrial processes. In this mini review, we address the recent trend in the synthesis of chiral heterogeneous catalysts and their subsequent application in asymmetric hydrogenation reactions. We focus on current advances in asymmetric hydrogenation reactions of C=O and C=C bonds due to their high relevance in the fine chemicals industry. Our main aim is to provide a short overview of this expanding field, its current challenges, and future perspectives.

Synthesis of Novel Pseudo-Enantiomeric Phase-Transfer Catalysts from Cinchona Alkaloids and Application to the Hydrolytic Dynamic Kinetic Resolution of Racemic 3-Phenyl-2-oxetanone.

Naturally occurring Cinchona alkaloids such as quinidine (QD)/cinchonine (CN) and their diastereomers, quinine (QN)/cinchonidine (CD), have been recognized as pseudo-enantiomeric pairs. Utilizing these pseudo-enantiomeric alkaloids as chiral resources provides complementary enantioselectivity in many asymmetric reactions. During the screening of Cinchona alkaloid phase-transfer catalysts (PTCs) in the hydrolytic dynamic kinetic resolution of racemic 3-phenyl-2-oxetanone (1) to tropic acid (2), we found that the introduction of a 4-trifluoromethylphenyl group at the vinyl terminus of BnQN significantly reduced the enantioselectivity to 41% enantiomeric excess (ee). The optimized structure of tetrahedral intermediates (TI, PTC + 1 + OH-) of hydrolysis obtained by density functional theory (DFT) calculations shows that the orientation of the quinoline and benzene rings of QD class PTC are nearly parallel to each other and to construct a greatly extended π-electron cloud surface, allowing good π-π interaction with the benzene ring of 1.

In-situ biosynthesis of metallic nanoparticles using Allium sativum and Chondrilla juncea extract: characterization and application in dye decolorization

The synthesis of catalysts has gained specific concern due to their versatile applications in particular azo dye decolorization. In the current work, metallic nanoparticles (copper and silver) were In-situ biosynthesised using Allium sativum and Chondrilla juncea extract. The obtained Allium-copper oxide and Allium-silver oxide materials were analyzed using SEM, TEM, FT-IR, TGA-DTG, SEM, TEM, and XRD techniques. Allium peels had a rough surface, with nanoparticles equally distributed over it. The crystal structure of Allium peels was altered after the addition of CuO and AgO nanoparticles. The highest residual mass values in the prepared materials indicated that the metallic nanoparticles were, in situ, formed. The prepared materials had worse thermal stability than Allium peel powders. The azo dyes, Calmagite and Naphthol Blue Black B were tested in the catalytic power of the resulting materials. The decolorization process was affected by the dye structure, amount of H2O2, dye concentration, time of reaction, and temperature of the bath. The activation energy values for Allium-CuO were 18.44 kJ mol−1 for calmagite, and 23.28 kJ mol−1 for naphthol blue black, respectively. Nevertheless, the energy values for Allium-AgO were 50.01 kJ mol−1 for calmagite and 12.44 kJ mol−1 for Naphthol blue black. The calculated low energy values for the prepared materials suggested the high efficiency of the use of these catalysts in azo dye decolorization under the change of some main experimental conditions.

Theoretical Catalyst Screening of Multielement Alloy Catalysts for Ammonia Synthesis Using Machine Learning Potential and Generative Artificial Intelligence

Theoretical Catalyst Screening of Multielement Alloy Catalysts for Ammonia Synthesis Using Machine Learning Potential and Generative Artificial Intelligence

In situ decorated pd NPs on Triazin-encapsulated Fe3O4/SiO2-NH2 as magnetic catalyst for the synthesis of diaryl ethers and oxidation of sulfides

This article is devoted to the synthesis of a new magnetic palladium catalyst that has been immobilized on A-TT-Pd coated-magnetic Fe3O4 nanoparticles. Such surface functionalization of magnetic particles is a promising method to bridge the gap between heterogeneous and homogeneous catalysis approaches. The structure, morphology, and physicochemical properties of the particles were characterized through different analytical techniques, including TEM, FT-IR, XRD, SEM, EDS, TGA-DTG, ICP, and VSM techniques. The obtained Fe3O4@SiO2@A-TT-Pd performance can show excellent catalytic activity for the synthesis of diaryl ethers and oxidation of sulfides, and the corresponding products were obtained with high yields. The advantages of this catalyst include a simple test method, green reaction conditions, no use of dangerous solvents, short reaction time, low catalyst loading, and reusability. Also, the nanocatalyst was easily separated from the reaction mixture with the help of a bar magnet and recovered and reused several times without loss of stability and activity.

Dynamic Reconstruction of Cu Catalyst under Electrochemical NO Reduction to NH3.

The electrochemical reduction of nitric oxide (NO) to ammonia (NH3) offers a sustainable way of simultaneously treating the air pollutant and producing a useful chemical. Among catalyst candidates, Cu emerges as a stand-out choice for its superb NH3 selectivity and production rate. However, a comprehensive study concerning its catalytic behaviorin the NO reduction environment is lacking. Here, we unravel the dynamic rearrangement of Cu catalysts during NO reduction: the emergence of a bundled nanowire structure dependent on the applied potential. This unique structure is closely linked to an enhancement in double-layer capacitance, leading to a progressive increase in current density from 236 mA cm-2 by 20% over 1 h, while maintaining a Faradaic efficiency of 95% for NH3. Characterizations of Cu oxidation states suggest that the nanostructure results from the dissolution-redeposition of Cu in the aqueous electrolyte, influenced by the interaction with NO or other reactive intermediates. This understanding contributes to the broader exploration of Cu-based catalysts for sustainable and efficient NH3 synthesis from NO.

Immobilization of carbon composite materials on structured frameworks for application in continuous catalytic experiments: Application in NO3- conversion

Bimetallic catalysts applied for water treatment are highly susceptible to deactivation/poisoning mainly when immobilized in macroscopic structures. Metal support interaction characteristic of metal oxides/composite supports emerges as an important strategy for controlling this phenomenon.This work explores a novel washcoating methodology to synthesize macrostructured composite catalysts for selective nitrate reduction. This approach allowed to effectively integrate powder composite materials into macroscopic frameworks, allowing to take advantage of modifications performed in the powder materials, often associated with increased catalytic activity/selectivity.Pd-Cu composite materials (metal oxides with carbon nanotubes) were prepared/tested for nitrate conversion. Titanium dioxide composites achieved the best performance (54 % nitrate conversion and 61 % N2 selectivity), outperforming the results obtained with more conventional synthesis methodologies. The catalysts proved to be highly active and resistant over several hours of reaction. This is a pioneering work focused on the synthesis and application of macrostructured composite catalysts in G-L-S (gas-liquid-solid) treatment systems.

Synthesis and Electrochemical Characterization of Ru-Modified Iridium Oxide Catalysts for PEM Electrolysis

Synthesis and Electrochemical Characterization of Ru-Modified Iridium Oxide Catalysts for PEM Electrolysis

Nanoflower-like NiCoFe layered hydroxide by in-situ electrochemical corrosion as highly efficient electrocatalyst for water oxidation

Layered double hydroxides have been widely applied for oxygen evolution reaction (OER) in the alkaline water electrolysis. However, the issues of poor connection between the catalyst and nickel foam and the specific mechanisms for active sites has not been fully documented. In this study, the in-situ nickel foam etching in a mixed solution of ferric chloride and cobalt nitrate at low temperatures was adopted for NiCoFe layered ternary hydroxides (NiCoFe LTHs) synthesis with a better tight integration. Physicochemical characterization indicated that the NiCoFe LTHs could grow directly through corroding nickel foam with a nano-flower-like morphology and structures. That is favorable for electron transfer from the catalytic layer to the conductive substrate. With the transition metal ions interaction and the tight integration construction, NiCo1Fe4-LTH-T60/NF presented an enhanced electrolysis performance with the overpotential of 234 mV (1.464 V vs. RHE) at current density of 100 mA cm−2 in 1 M KOH electrolyte. The Tafel slope for NiCo1Fe4-LTH-T60/NF electrode was 36.19 mV dec−1 for an enhanced OER kinetics. Besides, it demonstrated faster interfacial charge transfer process, better intrinsic electrochemical activity and stability in large current stability testing. It was revealed that the synergistic effect of the transition metal ions interaction enhancement and the mechanism of oxygen evolution elementary reaction for NiCo1Fe4-LTH-T60/NF during the water electrolysis by the electrochemical and theoretical calculation. This work provides theoretical basis and experimental support for the design and synthesis of future OER catalyst and substrate, which is significant for hydrogen and oxygen generation from water electrolysis.

Facile and Environmentally Friendly Synthesis of Ga2O3/MFI Catalysts for Propane Dehydrogenation.

A GaOx-based catalyst is recognized as a promising catalyst for dehydrogenation of light alkanes. Conventionally, impregnation and calcination are necessary processes for the loading of GaOx. However, the incomplete impregnation of gallium salt solution would generate wastewater, and the calcination for the dissociation of gallium salt would release harmful gases, such as SOx, NOx, and HCl. Meanwhile, the high temperature results in an excessive energy cost and undesired GaOx particle aggregation. Here, we report a facile and environmentally friendly method for the synthesis of GaOx-based catalysts. The gallium salt solution was replaced directly with liquid gallium (LG). Through a simple physical mixing method at room temperature, uniform GaOx nanoparticles with diameters of around 3.5 nm were loaded onto the surface of silicalite-1 (S-1). With the optimal GaOx/MFI catalyst, the propane conversion and propylene selectivity reached 22.9 and 90.1%, respectively, in the propane dehydrogenation reaction. The work offers a clean and economical strategy utilizing liquid metal (LM) as an impregnation solution for the preparation of GaOx-based catalysts.