Magnetic Nanocatalyst Research Articles

Preparation of New Aminodimethyl(Methylsulfonyl)Dihydropyrido[2,3-d]Pyrimidinedione Derivatives in the Presence of Fe3O4@SiO2@[O-(CH2)2-NH2][CH3CO2H] as Novel Nanocatalyst

An efficient synthesis of new aminodimethyl(methylsulfonyl)dihydropyrido[2,3-d]pyrimidinedione derivatives via the three components reaction of 2-methanesulfonylacetonitrile, 1,3-dimethyl-6-amino-uracil, and aromatic aldehydes in the presence of [HO-(CH2)2-NH2][CH3CO2H] and Fe3O4@SiO2@[O-(CH2)2-NH2][CH3CO2H] as novel heterogeneous magnetic nanocatalyst was described. The Fe3O4@SiO2@[O-(CH2)2-NH2][CH3CO2H] as nanocatalyst can be easily separated from the reaction mixture by an external magnet, recycled, and reused several times without any significant decrease in catalytic activity. These methods showed several advantages, including high yields, easy operation, and environment-friendly protocols.

Based on magnetically recoverable catalysts: a green strategy to sulfonamides.

The synthesis of sulfonamides, a class of compounds with significant pharmaceutical and medicinal applications, has seen remarkable advancements with the advent of magnetic nanocatalysts. Magnetic nanocomposites are one of the most efficient and widely used catalysts, and they are in complete harmony with the principles of modern green chemistry from the point of view of catalysis. These catalysts, typically composed of metal complexes supported on magnetic nanoparticles, offer unique advantages such as ease of recovery and reusability, which are crucial for sustainable and eco-friendly chemical processes. This review comprehensively examines recent developments in applying magnetic nanocatalysts to prepare sulfonamides. Key focus areas include the design and synthesis of various magnetic nanocatalysts (MNC), their catalytic performance in different reaction conditions, and mechanistic insights into their catalytic activity. By summarizing the latest research and technological advancements, this article aims to provide a valuable resource for researchers and practitioners in catalysis and pharmaceutical chemistry.

Optimizing catalytic performance: Reduction of organic dyes using synthesized Fe3O4@AC magnetic nano-catalyst

This article presents a sustainable method for the catalytic reduction of both simple and binary dye systems using magnetic activated carbon (Fe3O4@AC) synthesized from almond shells, an agricultural waste biomass. The reduction of methylene blue (MB) and Congo red (CR) was investigated in the presence of NaBH4, and a series of physical-chemical experiments were conducted to elucidate the mechanism of dye conversion and its performance. The results confirmed the successful synthesis of Fe3O4 nanoparticles on the activated carbon surface. The calculated rate constants in a simple system were 0.34 min⁻1 for MB and 0.25 min⁻1 for CR, in the binary system, the Fe3O4@AC catalyst demonstrated enhanced selectivity for the cationic MB dye, attributable to the robust, attractive surface charge. The study aimed to enhance catalytic performance by employing optimization curves generated from a three-level Box-Behnken Design (BBD) simulation. Experimental results indicated that the optimal catalyst dose, dye concentration, and reaction duration were 4–7 mg, 80–120 mg/L, and 5–20 min, respectively. Response surface methodology (RSM) was developed by processing the findings from 17 replicated experiments using a two-quadratic polynomial model, establishing a functional link between the experimental parameters and MB conversion. Optimal conditions for MB conversion were determined to be 7 mg of catalyst, 80 mg/L of MB concentration, and a reaction time of 12.5 minutes, resulting in an estimated conversion rate of 99.99 %. This prediction was validated by experimental findings, with regression analysis confirming a high correlation (R2 > 0.99) between the predicted and observed values. Additionally, the Fe3O4@AC catalyst demonstrated good recyclability and stable performance over three consecutive cycles, maintaining high conversion efficiency without loss of performance. These findings demonstrate that Fe3O4@AC is a viable approach for the rapid and efficient remediation of dyes in water.

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.

Marine-derived magnetic nanocatalyst in sustainable ultrasound-assisted synthesis of 2,3-diphenyl-2,3-Dihydroquinazolin-4(1H)-One derivatives

This research presents a sustainable approach to fabricate iron oxide nanoparticles by employing phytochemicals derived from marine grass extract as both reducing and stabilizing agents. Formation of magnetic nanoparticles (MNPs) initially confirmed by ultraviolet–visible spectroscopy (UV–vis) showing absorption peak at 370 nm. X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques unveiled magnetic iron oxide NPs with a rod shape, an average size of 21 nm, and an inverse spinel crystal structure. The participation of organic compounds in the production and stabilization of MNPs was evidenced through Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). A vibrating sample magnetometer (VSM) demonstrated the magnetic properties of iron oxide NPs showing a saturation magnetization value of 21.46 emu/g. The catalytic efficiency of these marine-assisted MNPs was evaluated in a one-pot three-component reaction involving isatoic anhydride, aromatic aldehydes, and amines under ultrasonic conditions. Under optimal conditions, a low dose of 1.5 mg of biobased magnetite nanoparticles yielded dihydroquinazolin-4(1H)-One products with up to 95 % efficiency in a brief duration of 15 min at an ultrasonic power intensity of 130 W. Different directing groups were investigated, and control experiments were carried out to enhance the understanding of the reaction mechanism. The obtained results highlight the synergistic effect of marine grass-mediated magnetic nanocatalysts combined with ultrasonic-assisted synthesis in developing sustainable green methodologies in organic synthesis.

Kinetic and optimization study of ultrasound-assisted biodiesel production from waste coconut scum oil using porous CoFe2O4@sulfonated graphene oxide magnetic nanocatalysts: CI engine approach

In this study, CoFe2O4@sulfonated graphene oxide (SGO) heterogeneous nanocatalyst was synthesized and utilized to produce biodiesel from waste coconut scum oil (WCSO). The structural features of CoFe2O4@SGO nanocatalyst were evaluated by SEM, TEM, EDX, FTIR, XRD, CO2/TPD, VSM, and BET analyses. According to these analyses, CoFe2O4@SGO nanocatalyst has high specific surface area, suitable functional groups, and good reactivity. The highest biodiesel yield using CoFe2O4@SGO nanocatalyst in optimal conditions (MeOH/WCSO ratio = 12.41, temperature = 64.73 °C, catalyst concentration = 2.24 %, and ultrasonic time = 33.08 min) was 96.87 %. The yield of biodiesel decreased from 96.91 % to 90.17 % after six reuse cycles, which demonstrates the significant stability of CoFe2O4@SGO nanocatalyst in the transesterification process. After 7 reuse steps, XRD and CO2/TPD analyzes revealed that the catalytic activity and crystallinity of the nanocatalyst were almost retained. The kinetic behavior of biodiesel generation showed that the transesterification reaction is endothermic. Enhancing the concentration of biodiesel in the fuel mix had a positive impact on the reduction of CO and UHC emissions, as well as diesel engine parameters such as cylinder pressure, BP, EGT, BSFC, and BTE. Owing to the high biodiesel yield, significant reusability, and positive impacts on the diesel engine, CoFe2O4@SGO nanocatalyst is recommended for industrial applications.

Research on synthesis of imidazopyridine-sulfide-aryl derivatives: copper complex immobilized on Fe3O4 nanoparticles catalyzed one-pot C–H bond sulfenylation of imidazopyridines

This research report the development of an eco-friendly, magnetic nanocatalyst, Fe3O4@SiO2-ABHA-CuCl, for the efficient synthesis of diaryl sulfides incorporating imidazo[1,2-a]pyridine scaffolds. The catalyst was successfully prepared by immobilizing CuCl on magnetic Fe3O4 nanoparticles modified with 4-amino-3-hydroxybenzoic acid. Characterization revealed spherical nanoparticles with a size range of 15-30 nm. The catalyst exhibited excellent catalytic activity in promoting C–H bond sulfenylation of imidazopyridines using the green solvent PEG-400. Remarkably, the catalyst demonstrated exceptional recyclability over eight consecutive cycles without significant loss of activity. Comprehensive analysis confirmed the preservation of the catalyst's magnetic properties and structural integrity after repeated use.

Synthesis and Characterization of Fe3O4@SiO2@APIDSO3H as a Novel and Efficient Magnetic Nanocatalyst in Pechmann Condensation

ABSTRACTFe3O4@APIDSO3H as a novel and magical magnetic nanocatalyst was designed, synthesized, and characterized by different spectroscopic techniques such as Fourier transform infrared (FT‐IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), x‐ray diffraction (XRD), energy‐dispersive x‐ray (EDX), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM). The loading percentage of sulfonic acid on the magnetic nano catalyst was calculated using CHNS analysis. Then, the potential use of it was investigated for the synthesis of various coumarins by Pechmann condensation. The corresponding products were synthesized and isolated in 60%–99% yields. The catalyst was recycled and reused for four times without loss in catalytic activity.

Magnetic Ru nanocatalysts for green solvent-free oxidation reactions of aromatic alcohols

A kind of magnetic hybrid organic-inorganic nanoparticles containing Ru metal (Fe3O4@SiO2-FPBA-Ru) was prepared. It was spherical with the characteristic lattice fringe of ruthenium atom. The size was in the range of 5–15 nm and it contained 0.30 mmol/g Ru. Its saturation magnetization value was 15.95 emu/g, which could be easily and efficiently recovered from solution through an external magnet. It was also stable below 240°C and hot filtration experiment proved Ru wasn't leaked from Fe3O4@SiO2-FPBA-Ru in 70°C oxidation reaction. It could be recovered and reused at least 7 cycles. The low amount of Fe3O4@SiO2-FPBA-Ru (75 mmol%) could convert the 99 % of 1-phenylethanol to acetophenone under solvent-free system, which verified its green and environment-friendly properties. The yield was exceed that of homogeneous (RuCl3, 85 %). Beside this, the TON (5181), TOF (7430 h−1) in oxidation of 1-phenylethanol and high conversion yields for a series of oxidation reactions of aromatic secondary alcohols proved the high catalytic ability of Fe3O4@SiO2-FPBA-Ru. These laid a foundation for its industrial applications.

Synthesis and application of an effective magnetic catalyst immobilized copper oxide for the one-pot ultrasound-assisted synthesis of 1,4-dihydropyridines

In this study, Fe3O4 was modified with a biocompatible carbohydrate D-(+)-ribonic γ-lactone (RL) followed by immobilization with CuO nanoparticles (CuO NPs) to produce Fe3O4-APTES-RL-CuO as a Lewis acid catalyst. The sustainable RL can be utilized as a novel support for CuO NPs with increased catalytic activity. RL with plenty of hydroxyl groups not only catch the CuO NPs and prevents them from agglomeration but also, prevails upon immobilization of CuO NPs making the nanohybrid RL-supported CuO NPs significantly stable. This green and effective heterogeneous catalyst can be used for one-pot ultrasound-assisted synthesis of 1,4-dihydropyridines (1,4-DHPs) with high yield (95٪) and short time (15 min). The catalyst can be separated easily and cleanly by using an external magnet. This nanomagnetic catalyst is reused five times without any remarkable reduction in its activity. To illustrate the structure of the catalyst and characterize its physicochemical properties, different techniques like FT-IR, XRD, FE-SEM, EDS, TGA, and VSM were applied.

Catalytic merits of Ni0.6Zn0.4Fe2O4/f-MWCNTS–CS–Asp/Ni2+ for tailoring 1H-benzo [4,5] imidazo [1,2-b] [1,2,4]triazepine motifs through green domino strategy

The magnetic nano catalyst mediated synthesis of heterocycles is one of the most fascinating fields of chemistry due to its proven applicability in high-efficiency, eco-friendly and recyclable heterogeneous catalytic system. In order to design a novel Ni0.6Zn0.4Fe2O4/f-MWCNTs–CS–Asp/Ni2+ magnetic heterogeneous catalyst, Ni0.6Zn0.4Fe2O4-decorated multi walled CNTs were modified with crosslinked chitosan with l-aspartic acid entrapped Ni2+ nanoparticles. This nano catalyst showed significant catalytic activity in the synthesis of biologically potent novel seven membered heterocycles embracing fused 1H-benzo [4,5]imidazo [1,21,2-b][1,2,4]triazepine skeleton. Owing to its interesting structure and being an important pharmacophore fragment, it was endeavored to exploit its synthesis. For the first time considering an exquisite and accomplishable access to construct (Kaur et al., 2021; Jiang et al., 2006; Stern, 1980) [1,2,4]triazepine framework. In addition, the structures of synthesized heterocycles and morphology of nano catalyst were corroborated on the basis of various spectroscopical and microscopical techniques. Furthermore, employing ultrasonication as energy source in the synthesis of magnetic nano catalyst employing 3R's (reduce, recycle and reuse), mild reaction conditions with appreciable yield along with no consumption and production of hazardous chemicals put it under the umbrella of green and sustainable approach.

Preparation of functionalized magnetic nanoparticles bearing sulfonic acid as an effective reusable solid acid catalyst for the synthesis of benzothiazoles

In this study, solid acid magnetic nanoparticles Fe3O4@SiO2-S-Bu-SO3H were prepared under appropriate conditions and characterized by various analytical techniques including FT-IR, XRD, FE-SEM, EDX, and VSM. Finally, the catalytic activity of the synthesized Fe3O4@SiO2-S-Bu-SO3H MNPs was investigated for the synthesis of valuable benzothiazole derivatives by the condensation reaction of ortho-aminothiophenol and various aldehydes under ultrasonic conditions. In the presence of the inexpensive, environment-friendly, magnetically recoverable solid acid catalyst, the benzothiazoles were obtained as pure target products in excellent yields (90–98%) and short reaction times (3–11 min). The synthesized Fe3O4@SiO2-S-Bu-SO3H MNPs show great catalytic activity because of the combined effect of Brønsted acidity and high functional group density. This solid acid magnetic nanocatalyst is reusable for several cycles and can be easily segregated from the reaction mixture.

Biodiesel synthesis from waste coconut scum oil utilizing SnFe2O4/cigarette butt-derived biochar as a magnetic nanocatalyst: Optimization, kinetic and thermodynamic study

This study aims to develop a novel and efficient magnetic nanocatalyst for producing biodiesel from waste coconut scum oil (WCSO). In this regard, a retrievable and robust nanocatalyst, SnFe2O4/biochar derived from cigarette butts, was synthesized and applied in the transesterification of WCSO under ultrasonication. The aforementioned nanocatalyst was synthesized by sol-gel technique. Various analyses were conducted to characterize the prepared nanocatalyst. These analyses confirmed the successful decoration of biochar on SnFe2O4. The Surface area and pore diameter were 128.47 m2/g and 15.62 nm, respectively. Central composite design (CCD) was applied to optimize the parameters influencing biodiesel synthesis. Moreover, the highest biodiesel yield employing SnFe2O4/cigarette butt-derived biochar nanocatalysts was attained at 98.67 % under optimal conditions, which include a methanol/WCSO ratio of 11.81:1 mol/mol, ultrasonic time of 34.25 min, temperature of 64.05 °C, and a catalyst amount of 2.73 wt%. Besides, SnFe2O4/cigarette butt-derived biochar demonstrated a notable biodiesel yield (90.48 %) even after seven reuse steps, highlighting its exceptional reusability. The thermodynamic and kinetic analyses of transesterification indicate that the synthesis of biodiesel is an endothermic reaction. The SnFe2O4/cigarette butt-derived biochar nanocatalyst stands out as a highly promising candidate for future research due to biodiesel performance, quick reaction time, and remarkable catalyst reusability.

A magnetic nanocatalyst based on Bronsted acid and Lewis acid centers for the efficient synthesis of polycyclic melting 1,5-benzodiazepines

In this study, 3-(Triethoxysilyl)propyl chloride (CPTES) was used to modify the surface of magnetic nanoparticles Fe3O4@SiO2, and aminomethylphosphonic acid (AMPA) was further anchored on the surface. Then, Ce (III) was used as the ligand to immobilize the surface of the modified material with N/O as the donor. Magnetic nanocatalysts (Fe3O4@SiO2@CPTES@AMPA@CeCl3) were successfully prepared. The prepared catalysts were characterized by infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen absorption-desorption experiment (BET), vibrating sample magnetometer (VSM), energy dispersive spectroscopy (EDS) and inductively coupled plasma atomic emission spectrometry (ICP-AES). A synergetic effect of Brønsted and Lewis acid (AMPA and CeCl3) of the magnetic nanocatalyst was examined to active carbonyl, imine or enamine bonds for the synthesis of polycyclic fused 1,5-benzodiazepine with quaternary carbon centers or quinoxaline ring in a one-pot method. It was found that this catalyst exhibited excellent catalytic activities (TON up to 111368, TOF up to 110232 h−1) and high selectivities in the synthesis of fused 1,5-benzodiazepine compounds (22 examples, 85–96 % yields). The mechanism for the synthesis of polycyclic fused 1,5-benzodiazepine catalyzed by Fe3O4@SiO2@CPTES@AMPA@CeCl3 was proposed. The nanocatalyst was readily recovered by simple magnetic decantation and can be recyclable without obviously reducing catalytic activity up to seven times.

Synthesis and characterization of CuCoFe2O4@GA/AC as a bio-based matrix magnetic nano-heterogeneous photocatalyst for ceftriaxone degradation from aqueous media

Emerging contaminants such as ceftriaxone are a significant issue in the environment. They have led to a series of ecological, environmental, and health issues, and it is urgent to find a green and secure method to remove antibiotics from water effectively. In this research, the CuCoFe2O4@Gum Arabic (GA)/Activated Carbon (AC) as an innovative bio-based matrix magnetic nanocatalyst was synthesized for the efficient degradation of ceftriaxone from aqueous media. The structure of CuCoFe2O4@GA/AC was characterized via FESEM, EDS, Mapping, XRD, FTIR, VSM, and DRS analyses. The structural analysis of the catalyst revealed its synthesis at the nanometer scale (40–50 nm), exhibiting high magnetic strength (Ms: 5.38 emu/g) and favorable optical properties with a bandgap of 3.6 eV. Under optimized conditions, including a pH of 5, 60 min of irradiation time, 0.24 g/L photocatalyst dose, and ceftriaxone concentration of 5 mg/L, the removal efficiency from synthetic and real samples was 94.43% and 62.5%, respectively. The photocatalytic degradation process of ceftriaxone followed pseudo-first-order and Langmuir–Hinshelwood kinetic models. Furthermore, analysis of the process mechanism indicated a prominent role of the superoxide radical. The catalyst had a high recovery capability and chemical stability. The photocatalytic degradation of ceftriaxone by CuCoFe2O4@GA/AC showcased remarkable efficiency, indicating its potential utility in the treatment of wastewater contaminated with antibiotics.

Dapsone-copper Functionalized Magnetic Nanocatalyst for the Preparation of Triazoloindazole Triones under Solvent-free Conditions

Dapsone-copper Functionalized Magnetic Nanocatalyst for the Preparation of Triazoloindazole Triones under Solvent-free Conditions

Gly-Pyrrole@SO3 coated on the surface of Fe3O4 (Fe3O4@Gly-Pyrrole@SO3H) as a new recyclable magnetic nano-catalyst for the synthesis of 2-amino-3-cyano-4H-pyrans and polyhydroquinolines

Gly-Pyrrole@SO3 coated on the surface of Fe3O4 (Fe3O4@Gly-Pyrrole@SO3H) as a new recyclable magnetic nano-catalyst for the synthesis of 2-amino-3-cyano-4H-pyrans and polyhydroquinolines

Deciphering the catalytic activity of nickel anchored on Fe3O4@SiO2@3-CPMS@L as a magnetically recoverable nanocatalyst for the efficacious reduction of 4-nitrophenol, nitrobenzene, and methyl orange

In this paper, a versatile heterogeneous nanocatalyst was fabricated employing a self-assembly technique. To commence, Fe3O4 MNPs were coated with a thin layer of SiO2 using the stobbers method. Subsequently, the surface was further functionalized with 3-CPMS, followed by a reaction with a Schiff base. Finally, nickel NPs were deposited on the surface through in situ deposition, forming the Fe3O4@SiO2@3-CPMS@L-Ni magnetic nanocatalyst. The architecture of this magnetic nanocatalyst was meticulously characterized through an array of sophisticated techniques: XRD, FT-IR, SEM, TEM, BET and VSM. The XRD diffraction pattern confirmed the presence of Fe3O4 MNPs, SiO2, and Ni peaks, providing evidence for successful synthesis. Moreover, the successful functionalization with a Schiff base was demonstrated by the presence of an azomethane peak in the FTIR spectra of the synthesized nanocatalyst. The fabricated nanocatalyst was adeptly utilized for the reduction of 4-NP, NB, and MO demonstrating a remarkably elevated rate of catalytic efficacy. Moreover, this catalyst was effortlessly retrievable through the application of an external magnet, and it maintained its catalytic prowess across at least six consecutive cycles. The utilization of water as an environmentally friendly solvent, coupled with the utilization of abundant and cost-effective nickel catalyst instead of the costly Pd or Pt catalysts, along with the successful recovery and scalability of the catalyst, render this method highly advantageous from both environmental and economic perspectives for the reduction of 4-NP, NB, and MO.

Nanostructured Iron (III)-Copper (II) Binary Oxide as a Highly Efficient Magnetically Recoverable Nanocatalyst for Facile One-pot Synthesis of 2, 4, 5-trisubstituted Imidazole and 1, 4-dihydro Pyridine Derivatives under Solvent-free Conditions

Abstract: The Fe (III)-Cu (II) binary oxide magnetic nanocatalyst emerges as an environmentally friendly and highly efficient solid acid catalyst, demonstrating remarkable utility in the one-pot synthesis of 2, 4, 5-trisubstituted imidazole and 1,4-dihydropyridine compounds, all achieved under solvent-free conditions. A facile co-precipitation method was used to synthesize nanostructured Fe-Cu binary oxide. Notably, this Fe-Cu binary oxide magnetic nanocatalyst proves its eco-friendly credentials as an exceptionally efficient and reusable catalyst, offering ease of handling, recovery, and multiple uses with minimal reactivity loss. Furthermore, the Fe (III)-Cu (II) binary oxide magnetic nanocatalyst's magnetic separability enhances its practicality, allowing for effortless catalyst retrieval after reactions. Significantly, the structural characteristics are meticulously elucidated through advanced analytical techniques, including 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. This work presents a versatile and sustainable solution for catalysis, with wide-reaching implications for green chemistry and the development of reusable, efficient catalysts for organic synthesis. The exceptional performance and eco-friendliness of the Fe-Cu binary oxide magnetic nanocatalyst underscore its practical significance. Fe-Cu binary oxide magnetic nanocatalyst exhibits the highest catalytic activity compared to others. The employment of this catalyst consistently delivers excellent yields in the target reactions, highlighting its potential to contribute positively to sustainable chemical processes.

Fabrication of Pd NCs@GO(Fe3O4) as a magnetically separable and reusable catalyst for catalytic conversion of three types of pollutants from water resources

In recent years, organic contaminants have become so detrimental to both the environment and human health that it is imperative to remove them from water. In this study, Magnetic Pd NCs@GO(Fe3O4) composite microspheres were successfully synthesized, which graphene oxide (GO) was encapsulated with Fe3O4 microspheres serving as the core, and subsequently, palladium nanocubes were deposited in situ onto the GO layer. The samples were thoroughly characterized using XRD, TEM, EDS, FT-IR, Raman, XPS, UV-Vis, VSM, DLS NMR and Zeta techniques. At room temperature, the presence of KBH4 effectively reduced 4-nitrophenol (4-NP), 4-nitroaniline (4-NA), and Congo red (CR). Specifically, 4-NP was fully reduced in three minutes with a TOF of up to 464 min⁻¹; 4-NA was completely reduced in seven minutes, achieving a TOF of up to 280 min⁻¹; And CR was fully reduced in eight minutes, yielding a high TOF of 74.86 min⁻¹. Furthermore, the magnetic Pd NCs@GO(Fe3O4) composite microsphere catalyst demonstrated excellent recovery and high conversion rates after five consecutive cycles, maintaining a minimum value of over 90 %. The reaction rate constants for the catalysts were found to be K4-NP = 1.12 min⁻¹, K4-NA = 0.606 min⁻¹, and KCR = 0.394 min⁻¹, respectively. The underlying catalytic mechanism was also discussed. Overall, this study presents a rapid and environmentally friendly method for synthesizing magnetic noble metal nanocatalysts for the efficient reduction of Congo red (CR), 4-nitroaniline (4-NA), and 4-nitrophenol (4-NP).