Magnetic Nanocatalyst Research Articles

Excellent Pd-Loaded Magnetic Nanocatalyst on Multicarboxyl and Boronic Acid Biligands.

An effective palladium nanocatalyst (Fe3O4@SiO2-FPBA-DTPA-Pd) was proposed and prepared, which was immobilized on magnetic silica with ethylenediamine pentaacetic acid and formylphenylboronic acid as biligands. A series of characterizations showed that Fe3O4@SiO2-FPBA-DTPA-Pd was 5-15 nm and contained 1.44 mmol/g Pd2+/Pd0. It was stable below 232.7 °C, and its saturation magnetization value was 21.17 emu/g which was easily recycled by a magnet. Its catalytic ability was evaluated through 7 Suzuki reactions and 15 Heck reactions. Results showed that the yields of 14 reactions catalyzed by Fe3O4@SiO2-FPBA-DTPA-Pd were more than 90%, while were better than those of the other two immobilized Pd catalysts on a single diethyltriamine pentaacetic acid (DTPA) group or boronic acid group. Moreover, Fe3O4@SiO2-FPBA-DTPA-Pd showed good reusability in both Suzuki and Heck reactions. In two model Suzuki and Heck reactions, after seven cycles, its yields were still above 95% without significant loss, which exceeded those of many reported catalysts; therefore, it has great potential in future large-scale industrial production.

A novel Cu(II) nanoparticles anchored on cyanuric chloride-attached magnetic nanocatalyst: A highly stable, recyclable and efficient nanocatalyst for the synthesis of chromene derivatives

As a novel core-shell magnetic nanocatalyst, a copper nanocatalyst, Cu(II)-Schiff base-TCT-APTES@SiO2@Fe3O4 was successfully synthesized through the reaction of the cyanuric chloride grafted onto the core-shell magnetic nanocatalyst with Schiff base complex and finally treated with Cu(NO3)2·3H2O. The noteworthy point is that the novel Schiff base separated by employing hydrazine with 2-pyridinecarboxaldehyde was synthesized and purified by a simple washing and identified by FT-IR, 1H NMR and 13C NMR spectrums. The catalyst was studied relying on various techniques and spectroscopic procedures including FT-IR, SEM, TEM, XPS, XRD, VSM, BET, TGA, and ICP analyses. The TEM images indicated that the catalyst was synthesized with an average size of 37–47 nm and a spherical shape. BET analysis showed that our catalyst has been synthesized with mesoporous structure and high surface area (52.55 m2/g). Moreover, the XPS results clearly demonstrated the peak at 937.2 eV and 949.2 eV that was related to the presence of Cu(II) in structure of catalyst. Then, copper nanocatalyst was successfully tested for the one-pot three component reaction of chromene derivatives of various aldehydes, phenols (2-hydroxynaphthalene-1,4-dione, resorcinol and β-naphthol) and malononitrile in ethanol under reflux conditions. All products were obtained in excellent yields for a diverse range of aromatic aldehydes. TON and TOF numbers for the compound 4j with the highest yield were found to be 192 and 581.8 h−1, respectively. Further, the copper catalyst can be reused by external magnetic field over seven times with a negligible loss in activity, showing 0.08% leaching of Cu after 7 times recycling. Also, Density Functional Theory (DFT) calculations were carried out to investigate the electrostatic potential (ESP), natural bond orbital (NBO), images of HOMO and LUMO orbitals and drawing the reaction mechanism using total energy of reactant and product.

Magnetic field-assisted water splitting at ternary NiCoFe magnetic Nanocatalysts: Optimization study

This study addresses the enhanced splitting of water into H2 and O2 assisted with applied magnetic field at ternary NiCoFe catalyst. The catalyst's activity towards water electrolysis is enhanced in the presence of AC-induced magnetic field (B = 720 μT) and approaches the performance of Pt/C∥IrO2. That is the overpotential at a current density of 10 mA cm−2 (η10) is reduced by 90 mV and 210 mV for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. Besides, a significant reduction in the cell voltage of 0.3 V and a power saving of 215.6 kWh during the production of one kg of H2 are obtained when AC magnetic field of 720 μT is applied. A markedly high stability of the catalyst is obtained under magnetic field during a prolonged electrolysis. The magnetohydrodynamic effect is believed to drive water electrolysis at NiCoFe film by reducing the ohmic potential drop across the electrode/solution interface, and increases the rate of charge transfer at the catalyst surface. The results are explained by capacitance measurements revealing maximum capacitance of NiFeCo catalyst in the presence of AC magnetic flux of 720 μT. Thus, favourable adsorption conditions lead to accelerated kinetics of OER and HER.

Musa balbisiana colla banana flower derived magnetic heterogeneous nanocatalyst for cleaner biodiesel production from jatropha oil

Banana flower has been used to create a very effective magnetically separable basic heterogeneous nanocatalyst for the production of sustainable biodiesel using jatropha oil. The potentiality of the innovative catalyst was assessed through the study performed by fourier transform infrared (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET), and thermogravimetric (TG) analysis. The magnetic nanocatalyst appeared as quasi spherical and core/shell structure, with a mean size of 19.47 nm. The catalyst's significant calcium (3.5%) and potassium (32.4%) contents indicates that the catalyst is quite basic in nature. With a catalyst load and methanol to oil ratio of 6 wt% and 9:1 respectively at 60 °C, the synthesized basic nanocatalyst produced 97.2 ± 1.15% biodiesel yield in 60 ± 2 min. It was discovered that the catalyst's basicity and surface area were 0.612 mmol/g and 64.4 m2 g−1 respectively. The transesterification reaction proceeded via pseudo-first order kinetics with an activation energy (Ea) of 33.25 kJ mol−1. The transesterification process exhibits endergonic and non-spontaneous behaviour as suggested by the values of entropy change (ΔS) and enthalpy change (ΔH) as 20.785 and −4.43 kJ mol−1 K−1 respectively. The catalyst showed promising catalytic stability and reactivity up to 3rd cycle with sufficient magnetization value of 17.43 emu/g and potassium content of 22.38% which endorsed biodiesel yield of 91.5% at 3rd cycle.

New Cu(II) Schiff-base complex modified on magnetic nanoparticles: Oxidation and DFT investigation

A copper magnetic nanocatalyst was facilely synthesized by surface modification of silica magnetic nanoparticles (Fe3O4@SiO2) via reaction with 3-aminopropyltrimethoxysilane (Fe3O4@SiO2@APTMS), followed by a subsequent reaction with thiophene-2-carbaldehyde to form a Schiff base (Fe3O4@SiO2@SB). Sequentially, reaction with Cu(CH3COO)2·H2O in ethanol yielded Fe3O4@SiO2@[SB@Cu] (CH3COO)2. This nanomagnetic catalyst was comprehensively characterized using Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Thermogravimetric Analysis (TGA), and Vibrating Sample Magnetometry (VSM) techniques. The catalytic proficiency of these nanoparticles was evaluated through alkene and alcohol oxidation reactions. Under optimized conditions, the nanocatalyst exhibited significant efficacy in oxidizing styrene, cyclohexene, and benzyl alcohol, with notable selectivity values of 88 %, 100 %, and 100 % for the respective formation of styrene epoxide, 2-cyclohexene-1-one, and benzoic acid. The heterogeneous copper nanocatalyst offers advantages, including high conversion rates, facile separation, and exceptional selectivity in alkene and alcohol oxidation. Additionally, this study investigated density functional theory (DFT) methods, encompassing geometric optimization, natural charge analysis, molecular electrostatic potential maps, and vibrational normal modes of the chelating ligands.

The potential of biochar derived from banana peel/Fe3O4/ZIF-67@K2CO3 as magnetic nanocatalyst for biodiesel production from waste cooking oils

Using biomass-based catalysts in biodiesel production can make the process more economical and environmentally friendly. In this study, a new magnetic nanocatalyst was developed using banana peel biochar, ZIF-67, Fe3O4, and K2CO3, and then utilized in a catalytic transesterification process to convert waste cooking oils (WCO) into biodiesel. The level of free fatty acids of the treated WCO (WCOT) was reduced to generate a biodiesel with more suitable characteristics. The physicochemical aspects of the magnetic nanocatalyst were characterized by Fourier-transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) and map techniques. In the transesterification process, the effect of temperature, methanol-to-oil ratio, process time, and nanocatalyst weight on the potential of nanocatalyst to produce biodiesel from WCO and WCOT was explored. The highest yield of biodiesel from WCO (96.82%) and WCOT (99.18%) was attained at 65 °C, nanocatalyst weight of 3 wt %, methanol-to-oil ratio of 19:1, a processing time of 3 h, and a mixing rate of 600 rpm. Based on thermodynamic studies, the biodiesel production process was endothermic and non-spontaneous. The regeneration of the nanocatalyst was studied using various solvents and n-hexane had a good ability to recover the catalyst (90% up to 5 stages). The results of the 1H NMR test revealed that the desired nanocatalyst had a high potential to generate biodiesel from WCO and WCOT. The properties of produced biodiesel met ASTM D6751 and EN 14214 standards.

Imidazolium based Ionic liquid Anchored over Dendritic Mesoporous Silica Nanospheres possessing a Magnetic Core as an Efficient and Recyclable Base Catalyst

AbstractIn this study, Magnetic core‐shell dendritic mesoporous silica nanospheres immobilized with imidazolium‐based di‐cationic ionic liquid (Fe3O4@SiO2@DSiO2‐Im‐IL) possessing a large surface area and numerous active site for adsorption of various molecules to carry out organic transformations have been successfully developed. The synthesized nanocatalyst was found to be easily recyclable by applying external magnetic force. The structure, morphology, thermal stability, and magnetic behavior of the synthesized magnetic nanocatalyst were confirmed by different physiochemical techniques like FT‐IR, P‐XRD, FE‐SEM, TGA, VSM, BET, and TEM analysis. The efficiency of the developed heterogeneous nanocatalyst has been investigated for the green synthesis of numerous benzopyran derivatives by employing different aldehydes and active methylene compounds. The catalyst exhibits marvellous activity and efficiency in terms of high product yield, less catalyst use, and wide substrate scope even at room temperature. Finally, after the successful formation of the product, the catalyst was regenerated by utilizing an external magnetic field. The catalyst has been reused multiple times without any noteworthy loss in its activity which confirms the stability of the developed catalyst. The preparation of the catalyst is cost‐effective, and shows atom economy with the utilization of green solvent and without any waste production, which authenticates that it could be a greener pathway for the synthesis of the benzopyran derivatives.

Construction and characterization of Fe3O4@BAAH-CuCl nanomagnetic catalyst: catalysis research in synthesis of 2-aryl quinazolines from prepared benzylamines

We have constructed Fe3O4@BAAH-CuCl nanomagnetic catalyst in ChCl-Urea (choline chloride deep eutectic as solvent) as a highly efficient catalytic system for the preparation of 2-aryl quinazoline derivatives through one-pot, three-component reactions of 2-bromobenzaldehyde with primary amines and sodium azide under molecular oxygen. FT-IR, VSM, SEM, TEM, TGA, XRD, EDX, ICP-OES and elemental mapping analyses confirmed the fabrication of Fe3O4@BAAH-CuCl nanomaterial. In this project, we first prepared various derivatives of benzylamines from reduction of aryl nitriles, then used the benzylamine products as substrates in the three-component synthesis of 2-aryl quinazoline derivatives in the presence of Fe3O4@BAAH-CuCl/ChCl-Urea as an efficient catalytic system. Although the synthesized products (primary amines and 2-aryl quinazolines) were known, their physical state was confirmed with the reported samples in the literature and the structure of all the products confirmed by 1HNMR and 1CNMR.

Preparation, characterization and photocatalysis performances of superparamagnetic MgFe2O4@CeO2 nanocomposites: Synthesized via an easy and green sol–gel method

The characterization of MgFe2O4@CeO2 superparamagnetic nanocomposites was thoroughly investigated using powder X-ray diffraction (XRD), a vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), dispersive X-ray analysis (EDX), elemental mapping (MAP), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) and UV–Vis diffuse reflectance spectroscopy (DRS) analyses. The photocatalytic activity of the synthesized samples was evaluated as a novel magnetic nanocatalyst for degrading Congo red (CR) dye in an aqueous solution under visible light at room conditions. The results demonstrate that the efficiency of photocatalytic degradation is higher than that of absorbance and photolysis. The degradation efficiency of photodegradation is 93% within 49% of total organic carbon removal performance. The prepared MgFe2O4@CeO2 magnetic nanocomposites (MNCs) can be easily recovered and recycled for five repeated cycles, demonstrating potential extensive efficiency in magnetic nanocomposites in wastewater and water treatment. The nanoscale morphology of MgFe2O4@CeO2 MNCs was characterized as spherical, with a size range of 35–40 nm, utilizing SEM and TEM techniques. The saturation magnetization (Ms) of the resulting nanocomposites was analyzed by VSM, revealing a value of 3.58 emu/g. Furthermore, the surface area was determined to be 27.194 m2/g using BET analysis, and the band gap was identified as 2.85 eV through DRS analysis.

Magnetic nanocomposite based on chitosan-gelatin hydrogel embedded with copper oxide nanoparticles: A novel and promising catalyst for the synthesis of polyhydroquinoline derivatives

Nanocatalysts are vital in several domains, such as chemical processes, energy generation, energy preservation, and environmental pollution mitigation. An experimental study was conducted at room temperature to evaluate the catalytic activity of the new gelatin-chitosan hydrogel/CuO/Fe3O4 nanocomposite in the asymmetric Hantzsch reaction. All components of the nanocomposite exhibit a synergistic effect as a Lewis acid, promote the reaction. Dimedone, ammonium acetate, ethyl acetoacetate, and other substituted aldehydes were used to synthesize diverse polyhydroquinoline derivatives. The nanocomposite exhibited exceptional efficacy (over 90 %) and durability (retaining 80 % of its original capacity after 5 cycles) as a catalyst in the one-pot asymmetric synthesis of polyhydroquinoline derivatives. Also, turnover numbers (TON) and turnover frequency (TOF) have been checked for catalyst (TON and TOF = 50,261 and 100,524 h−1) and products. The experiment demonstrated several benefits, such as exceptional product efficacy, rapid reaction time, functioning at ambient temperature without specific requirements, and effortless separation by the use of an external magnet after the reaction is finished. The results suggest the development of a magnetic nanocatalyst with exceptional performance. The composition of the Ge-CS hydrogel/CuO/Fe3O4 nanocomposite was thoroughly analyzed using several methods including FT-IR, XRD, FE-SEM, EDX, VSM, BET, and TGA. These analyses yielded useful information into the composition and characteristics of the nanocomposite, hence further enhancing the knowledge of its possible uses.

Synthesis and characterization of novel magnetic nano-catalyst (Fe3O4@SiO2@EDDHA-Fe) and their hydrogen production activity

Due to irreparable crises for nature and people, replacing fossil fuel-based energy with green energy sources is a necessity for nature and humanity. Hydrogen is considered a clean energy transport due to its high energy density, environmental friendliness, high efficiency, and recyclable nature. This study generated hydrogen through NaBH4 ethanolysis. In hydrogen production studies, there are very few studies with magnetic nano catalysts and very few studies with cheap transition metals. In order to contribute to the literature in this field, in this study, Fe3O4@SiO2@EDDHA-Fe was produced for the first time and used in hydrogen production studies. Fe3O4@SiO2@EDDHA-Fe synthesis was successfully carried out and hydrogen production was successfully implemented. The study also utilized FT-IR, XRD, VSM, BET, and SEM-EDX methods to characterize the structural, physical, and chemical properties of MNCs. The average particle diameter and magnetization value of Fe3O4@SiO2@EDDHA-Fe were 12.81 nm and 30.6 emu/g, respectively. The catalysis experiment designed with 50 mg Fe3O4@SiO2@EDDHA-Fe and 93.75 mM NaBH4 generated 840 mL H2/g NaBH4 298 K and 947 mL H2/g NaBH4 318 K in 5-min duration, respectively. At room temperature, the hydrogen generation rate (HGR) and activation energy (Ea) of Fe3O4@SiO2@EDDHA-Fe reaction were calculated as 1040 mL H2/gcat·min and 5.39 kJ/mol, respectively. After the sixth cycle, the reusability test of Fe3O4@SiO2@EDDHA-Fe reaction still retained approximately 87% of the initial hydrogen production volume. The study concluded that Fe3O4@SiO2@EDDHA-Fe is a promising catalyst in hydrogen production from NaBH4 ethanolysis, as it is affordable and easy to prepare compared to other expensive catalysts.

Synthesis and application of CoFe₂O₄@THAM@PHG‐SO₃H nanoparticles as a new and highly recyclable nanocatalyst in the one‐pot multicomponent synthesis of 3,4‐dihydropyranochromenes and chromeno[3,4‐b]quinoline‐6‐ones

In this study, we have developed a new environmentally‐friendly magnetic nanocatalyst by treating CoFe₂O₄ magnetic nanoparticles with chlorosulfonic acid, tris(hydroxymethyl)aminomethane (THAM), 1,2‐dichloroethane, and phloroglucinol (PHG). They confirmed the synthesis of the catalyst using various techniques such as FT‐IR, SEM, MAP, EDS, XRD, TGA, DTA, and VSM. The researchers then evaluated the catalytic efficiency of the nanocatalyst in two reactions: the synthesis of 3,4‐dihydropyranochromenes from the reaction among aromatic aldehydes, 4‐hydroxycoumarin, and malononitrile, and the synthesis of chromeno[3,4‐b]quinoline‐6‐ones from the reaction among aniline, 4‐hydroxycoumarin, and aromatic aldehydes.

Fe3O4@SA MNCs Synthesis, Characterization, and First-time Use in Hydrogen Production by NaBH4 Hydrolysis

Hydrogen is a clean energy carrier that will reduce dependence on fossil fuels and contribute to reducing the harmful effects on the environment resulting from using fossil fuels. Hydrogen is produced by the hydrolysis of sodium borohydride (NaBH4), one of the chemical hydrides, using a catalyst. In this study, Fe3O4@Salicylic acid magnetic nano-catalyst (Fe3O4@SA MNCs) was synthesized using the co-precipitation technique. The structural, physical, and chemical properties of the produced Fe3O4@SA MNCs were characterized by FT-IR, XRD, VSM, SEM, and SEM-EDX methods. At room temperature, the effect on hydrogen production performance was examined in the amounts of Fe3O4@SA MNCs (10, 25, 50, 75, and 100 mg), NaOH (0, 10, 20, and 25 mg), and NaBH4 (25, 50, 100, 150 and 200 mg). The highest hydrogen generation rates (HGR) were obtained using 10 mg Fe3O4@SA MNCs, 150 mg NaBH4, and 0 mg NaOH at room temperature. The obtained HGR value was calculated as 400 mL gcat-1.min-1. Fe3O4@SA MNCs were used for hydrogen production for the first time in this study. This study showed that Fe3O4@SA MNCs exhibit catalytic properties and are a promising, efficient catalyst in hydrogen production from NaBH4.

A Mini-review on Recent Advances in Synthesis of Dihydropyrano [3, 2-c] chromenes Using Magnetic Nanocatalysts.

The development of an active, selective, and long-term selective catalyst for the synthesis of biologically active heterocycles is still challenging. However, magnetic nanocatalysts have divergent applications like high efficiency, selectivity, consumption, and reusability. The current review explores a detailed survey of the latest information on synthetic methods of Pyrano [3, 2-c] chromene derivatives using different magnetic nanocatalysts. Numerous studies on the synthesis of these practical compounds have been stimulated by the special qualities and wide-ranging applications of pyrano coumarins and the nanoparticles were tested for their catalytic effectiveness in a one-pot, three-component reaction involving aldehydes, malononitrile, and 4-hydroxycoumarin for the manufacturing of dihydropyrano [3, 2-c] chromenes (coumarins).

Preparation and characterization of sulfamic acid-functionalized Fe3O4 nanoparticles as an efficient magnetic nanocatalyst for the facile and eco-friendly synthesis of quinoxalines, benzothiazoles, and benzoxazoles

Preparation and characterization of sulfamic acid-functionalized Fe3O4 nanoparticles as an efficient magnetic nanocatalyst for the facile and eco-friendly synthesis of quinoxalines, benzothiazoles, and benzoxazoles

An Attractive and Comprehensive Review on C-O Bond Formation: Nanomagnetic Recoverable Catalysts to Access Diaryl Ethers via C-O Cross-coupling Reactions

Abstract: The simple separation of magnetic nanocatalysts from the reaction mixture using only an external magnet caused a huge revolution in catalysis, particularly in organic synthesis. Diaryl ethers (compounds containing (Ar-O-Ar linkages) are one of the most important and prominent compounds and are widely found in natural products and pharmaceutical and biological molecules. The C-O cross-coupling or O-arylation reactions of aryl halides with aromatic alcohols, especially phenols, is an important and straightforward strategy for the preparation of diaryl ethers. Due to the high importance of diaryl ethers in the pharmaceutical, chemical and medical fields, many efforts have been made for the synthesis of diaryl ethers through C-O cross-coupling aryl halides with aromatic alcohols, especially phenols based on using non-magnetic reusable catalysts. In this review, we carefully reviewed the synthesis of diaryl ethers and discussed the reaction conditions and product yields in each method.

Decorated Magnetic Nanocatalyst with Trinitriloacetic Acid as a Heterogeneous Catalyst used in the Synthesis of Pyrimido[4,5]quinoline‐2,4‐diones

AbstractTo answer the challenges of using nitrilotriacetic acid (NTAA) as an efficient, recyclable, and durable acidic nanocatalyst, a novel, versatile, engineerable, affordable, eco‐friendly acidic heterogeneous magnetic nanocatalyst has been synthesized with high thermal stability and excellent catalytic efficiency through immobilization of NTTA on the surface of the functionalized magnetite core‐shell. Fe3O4@SiO2‐NH‐NTAA, has been synthesized and presented here. This nanomagnetic catalyst, Fe3O4@SiO2‐NH‐NTAA, was fully identified and characterized through analytical techniques such as FTIR, FESEM, TEM, EDX, elemental mapping, TGA‐DSC, DLS, VSM, and XRD, in addition to theoretical calculations based on DFT/B3LYP/6‐311++G(d, p). Its catalytic capability as well as easy separation, recoverability, and reuseability were examined in the one‐pot preparation of pyrimido[4,5]quinolone‐2,4‐diones under mild conditions, where the high performance of the Fe3O4@SiO2‐NH‐NTAA magnetic nano‐catalyst was proved by excellent reaction yield (>98 %) and the catalyst's recovery efficiency (>98 %). Due to the presence of NTAA's zwitterionic forms in the outermost layer of Fe3O4@SiO2‐NH‐NTAA, this acidic catalyst causes the progress and control of the three‐component reaction in this article well and in the desired direction.

ZnFe2O4@SiO2@L-Lisin@Cr-EDTA coordination polymer: A novel, green, magnetic, reusable, and versatile nanocatalyst for the oxidation of sulphides

In this research, the design, and synthesis of ZnFe2O4@SiO2@L-Lisin@Cr-EDTA coordination polymer magnetic nanoparticles as a novel, recyclable, and heterogeneous catalyst was developed. EDTA with four carboxylic groups as an outstanding chelating agent was utilized for the preparation of the Cr-EDTA metal-organic framework (Cr-EDTA coordination polymer). In the next step, by immobilizing the synthesized Cr-EDTA coordination polymer on the surface of the Zinc ferrite nanoparticles, ZnFe2O4@SiO2@L-Lisin@Cr-EDTA coordination polymer was synthesized. The magnetic nanocatalyst (ZnFe2O4@SiO2@L-Lisin@Cr-EDTA coordination polymer) was characterized by using various methods such as BET, FTIR, SEM, XRD, EDX, TGA, VSM, and Map analysis. Also, the oxidation of sulfides to sulfoxide was efficiently performed using the ZnFe2O4@SiO2@L-Lisin@Cr-EDTA coordination polymer catalytic system. The synthesized catalyst can be reused for five periods without loss of catalytic activity.

Preparation of recyclable magnetic palladium nanocatalysts by dispersion strategy based on sodium alginate for reduction of p-nitrophenol and Suzuki-Miyaura coupling

Palladium (Pd) has excellent catalytic performance, its application is seriously limited by low atomic utilization and weak recovery capacity. To solve these problems, we report a universal palladium nanocatalysts preparation strategy by taking advantage of the rich chemistry of sodium alginate (SA). SA units not only self-assemble into a cross-linked porous carboxyl and hydroxyl framework but also can coat different substrates. Benefiting from the distinguished chelation of SA, metallic nanocatalysts can be achieved. As a proof-of-concept demonstration, Pd loading on nano-Fe3O4 modified with SA and investigated their catalytic capabilities. The catalyst was Fe3O4 nanoparticles encapsulated by SA film loaded with 0.4 wt% of Pd. It has a particle size around 100 nm and has good superparamagnetism with a saturation strength of 76.26 emu/g. It exhibited good catalytic activity at TOF = 660 h−1 and TOF = 4311 h−1 in typical Suzuki-Miyaura coupling reaction and the reduction of p-nitrophenol, respectively, and showed appreciable recyclability in the test of recyclability. Thus, our findings demonstrate that recyclable magnetic palladium nanocatalysts have several attractive features, such as easy preparation, outstanding catalytic activity and reusability. This work lays the foundation for the preparation of palladium nanocatalysts and the potential application of SA in the field of catalysts.

Synthesis and characterization of a green and recyclable arginine-based palladium/CoFe2O4 nanomagnetic catalyst for efficient cyanation of aryl halides.

The utilization of magnetic nanoparticles in the fields of science and technology has gained considerable popularity. Among their various applications, magnetic nanoparticles have been predominantly employed in catalytic processes due to their easy accessibility, recoverability, effective surface properties, thermal stability, and low cost. In this particular study, cyanuric chloride and arginine were utilized to synthesize an arginine-based oligomeric compound (ACT), which was supported on cobalt ferrite, resulting in a green catalyst with high activity and convenient recyclability for the cyanation reaction of aryl halides. The Pd/CoFe2O4@ACT nanomagnetic catalyst demonstrated excellent performance in the cyanation of various aryl iodides and bromides, yielding favorable reaction outcomes at a temperature of 90 °C within a duration of 3 hours. The synthesized nanoparticles were successfully characterized using various techniques, including FTIR, FE-SEM, EDX/MAP, XRD, TEM, TGA, BET, and ICP-OES. Moreover, the Pd/CoFe2O4@ACT catalyst exhibited remarkable catalytic activity, maintaining an 88% performance even after five consecutive runs. Analysis of the reused catalyst through SEM and TEM imaging confirmed that there were no significant changes in the morphology or dispersion of the particles. Ultimately, it was demonstrated that the Pd/CoFe2O4@ACT nanomagnetic catalyst outperformed numerous catalysts previously reported in the literature for the cyanation of aryl halides.