Magnetic Catalyst Research Articles

Developing of α-Fe2O3/MoS2 embedded g-C3N4 nanocomposite photocatalyst for improved environmental dye degradation and electrocatalytic hydrogen evolution reaction performance

A novel g-C3N4/α-Fe2O3–MoS2 (GFMO) ternary nanocomposite has been successfully constructed by facile calcination-hydrothermal methods. As-obtained magnetic GFMO ternary composite catalyst was investigated with the excellent degradation efficiency of organic rhodamine B (Rh B) and methylene blue (MB) pollutants in aqueous solution (95.6 % and 91.1 %) in 80 min under visible-light. The active coupling of α-Fe2O3 co-catalyst accelerated photo-electron transfer, improved visible-light fascination, suppressed the recombination rate, and sustained charge separation ability. This demonstrates the synergistic effect of the intimated heterojunction interface among g-C3N4 and MoS2, liable for efficient photo-degradation response. The scavenging tests revealed that •O2− and h+ reactive species play a most vital part in the photocatalytic degradation of both dyes. Furthermore, better electrocatalytic hydrogen evolution reaction (HER) performance in typical acidic conditions, with a lower overpotential of 305 mV and a Tafel slope of 128 mV dec−1. As an outcome, the current work offers a novel insight into the development of efficient ternary g–C3N4–based photocatalysts (PCs) for wastewater refining and electrochemical hydrogen evolution reactions.

A green and pollution-free heterogeneous ruthenium catalyst anchoring on magnetic nanoparticles with FPBA and DTPA groups for oxidation of aromatic alcohols

Using ruthenium chloride as catalyst precursor, magnetic silicon spheres as support, 4-formylphenylboronic acid and ethylenediaminepentaacetic acid as functional ligands, a magnetic heterogeneous nano-ruthenium catalyst (Fe3O4@SiO2-FPBA-DTPA-Ru) was prepared for the first time. It was nano level with 20.17 emu/g saturation magnetic strength and thermal stability under 249.63 °C. Fe3O4@SiO2-FPBA-DTPA-Ru contained 0.38 mmol/g Ru and was successfully used to catalyze the oxidation reactions of 15 aromatic secondary alcohols. Results proved that Fe3O4@SiO2-FPBA-DTPA-Ru as catalyst had good catalytic activity for the oxidation of secondary aromatic alcohols with yields exceeding 90 % for 12 products and 95 % for 10 products. High TON and TOF values (6386 and 9158 h−1) in 1-phenylethanol oxidation were obtained. All the reactions of aromatic alcohols were carried out in a solvent-free system, so the prepared catalyst had the characteristics of green and pollution-free. It was’nt suitable for oxidation of aromatic primary alcohols. If there was steric hindrance around the hydroxyl group in substrate, the catalysis also may be limited. The Fe3O4@SiO2-FPBA-DTPA-Ru catalyst also exhibited the advantages of energy saving, satisfactory reusability and stability in 9 consecutive runs. It showed great potential for future large-scale industrial production.

NaAlO2/CuFe2O4 as a novel basic magnetic heterogeneous catalyst for effective biodiesel production: Synthesis, characterization, and optimization via RSM-FCCD modeling approach

This research focus on the development of a novel and superior basic magnetic heterogeneous catalyst, using NaAlO2 as an active species supported in CuFe2O4 to produce biodiesel. Thus, a series of catalysts have been synthesized by means of conventional and low-cost methods. The features of catalyst have been elucidated through techniques such as basicity, XRD, FTIR, SEM, EDS, TG/DTG and VSM. To optimize the biodiesel’s ester content, the face-centered central composite design with the response surface methodology, was employed to assess the effect of the aspects on the process: reaction temperature, MeOH:oil molar ratio, catalyst dosage and time. The regression model presented R2 = 0.9394 and experimentally reached a maximum ester content of 95.9 % attributed to the biodiesel attained under the optimal reaction conditions: temperature of 95.0 °C, MeOH:oil molar ratio of 13:1, catalyst dosage of 8.0 % and time of 60.0 min. The catalyst presented a stable catalytic performance during four transesterification cycles (>90.0 %) and an efficient magnetic property for the catalyst separation and recovery process (Ms = 23.62 emu g−1). The biodiesel’s physicochemical properties were in compliance with ASTM D6751 standard. Finally, this extensive study reveals the basic magnetic heterogeneous catalyst as a practical and promising alternative to produce a sustainable biofuel.

Fe3O4@Sal-cu as a highly efficient magnetic nano-catalyst for the synthesis of 2-substituted benzimidazoles under ultrasonic irradiation and solvent free condition

Fe3O4@propyl-semicarbazide-salicyl aldehyde-Cu (Fe3O4@sal-Cu) nanocatalyst was synthesized and characterized by several methods including XRD, SEM, EDX, VSM and FT-IR analyses. The Fe3O4@sal-Cu has been used as an efficient recyclable magnetic catalyst for the preparation of benzimidazoles. The catalyst was conveniently separated from the reaction mixture by an external magnet, and could be reused without any considerable change in catalytic activity.

Transesterification of used cooking oil by palm lignocellulosic biomass magnetic biochar catalyst: Optimization and kinetic analysis

Biodiesel has recently gained popularity as an alternative biofuel to substitute fossil fuel. Utilization of magnetic biochar catalyst (MBC) in biodiesel production can enhance the catalyst separation process. In this research, MBC was synthesized from oil palm waste such as palm kernel shell (PKS), oil palm frond (OFP), and empty fruit bunch (EFB). Biodiesel production parameters were studied using the Central Composite Design-based Response Surface Method. Based on the characterization results, EFB is the most suitable palm lignocellulosic biomass for MBC synthesis. The MBC has a BET surface area of 44.42 m2 g−1, an average acid density value of 3.85 mmol g−1, and a σs value of 3.19 Am2 kg−1. MBC synthesis is at its optimal by using 1.5 M FeCl3·6H2O solution, 800 °C carbonization temperature, and 2.5 M H2SO4. The optimized transesterification parameters are: catalyst loading of 10.25 wt%, methanol to oil molar ratio of 28, 70 °C, and 8 h gave a maximum fatty acid methyl ester yield of 91.50 %. After five cycles, the yield dropped to 67.37 %. Biodiesel production is reported to be the pseudo-irreversible first-order kinetic with an activation energy of 29.20 kJ mol−1. The physicochemical characterization showed the biodiesel has met the ASTM D6751 standard.

Microwave-Assisted Catalytic Deconstruction of Plastics Waste into Nanostructured Carbon and Hydrogen Fuel Using Composite Magnetic Ferrite Catalysts

Microwave-Assisted Catalytic Deconstruction of Plastics Waste into Nanostructured Carbon and Hydrogen Fuel Using Composite Magnetic Ferrite Catalysts

Facile fabrication of bifunctional ternary nanocomposite (FCPTNC) as an efficient catalyst for 4-nitrophenol reduction and crystal violet photodegradation

The synthesis of a ternary nanocomposite Fe3O4/CuO-Ppy (FCPTNC) was effectively achieved via hydrothermal and in-situ chemical oxidative polymerisation techniques. FCPTNC was used as a catalyst for reducing the toxic compound 4-nitrophenol to the non-toxic compound 4-aminophenol. Additionally, it was utilised for the visible-light-induced degradation of the crystal violet (CV) dye. FCPTNC underwent characterisation using various techniques, namely X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), ultraviolet–visible diffuse reflectance spectroscopy (UV-DRS), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR). The successful preparation of the nanocomposite was validated through analysis of its structural properties. Moreover, examining its optical properties indicated that the nanocomposite can effectively operate through visible light irradiation. The catalyst demonstrated exceptional catalytic efficacy in eliminating the targeted organic pollutants, namely 4-nitrophenol (4-NP) and crystal violet (CV). The catalyst exhibited a degradation efficiency of 97 % for CV dye within60 min. It achievedthecomplete conversion of 4-nitrophenol into its corresponding amino derivative within15 min. The calculated first-order rate constants for the reduction of 4-NP and photodegradation of CV dye were found to be in the range of 0.53–11.6 × 10−2 min−1 and 3.2–5.6 × 10−2 min−1, respectively. The magnetic catalyst exhibited efficient separation from the reaction media and was successfully recycled for up to fiveconsecutive cycles with negligible loss of catalytic activity. The work demonstrates that the FCPTNC nanocomposite has favourable characteristics, such as facilesynthesis, efficient catalytic activity, and reusability. These findings suggest that the nanocomposite possesses desirable efficiency and durability, rendering it a promising catalyst for environmental applications.

Supported Bis-(NHC)-Pd(II) complex: A phosphine-free catalyst supported on magnetic mesoporous silica for the CO-free carbonylation of aryl halides

In this work, our previously reported bis(NHC)-Pd(II) catalyst grafted on Fe3O4@SBA-15 has been successfully used as a phosphine-free heterogeneous magnetic catalyst in the CO-free carbonylation of aryl halides. It is shown that the immobilized Pd(II)-complex efficiently catalyzes the carbonylation of different aryl halides with HCOOH and DCC in the presence of Et3N as the base. Optimal reaction conditions were determined by screening various parameters such as solvent, HCOOH/DCC molar ratio, base, temperature, and catalyst dosage. The catalyst was magnetically retrievable and separated by an external magnet, washed, and re-used in the subsequent runs over seven catalytic cycles. The hot filtration experiment was conducted to determine the heterogeneous nature of the catalyst.

Synthesis of polyaniline-doped magnetic iron foam photo catalyst (PANI@mIF) for integrated adsorptive photocatalytic degradation of nicosulfuron

ABSTRACT Nicosulfuron have low volatility and slow biodegradation rate, leading to its long persistency in soil and crops, which further upraised the risk of contamination of nearby water and severe damage to the crop rotation as may be its precursors are more harmful than nicosulfuron itself. In the present work, we performed a degradation study for the efficient removal of nicosulfuron from soil and water using Polyaniline-doped magnetic iron foam (PANI@mIF). The Photo catalyst was synthesised by doping of polyaniline on magnetic iron foam at 70°C and applied for the efficient photocatalytic degradation of nicosulfuron. PANI@mIF was then characterised through FTIR, SEM, EDX and XRD. The degradation of nicosulfuron was investigated under UV radiations and the resulted data were examined by fitting isotherms models. The Langmair model is well fitted to the adsorption data with R2 of 0.925, which demonstrates monolayer adsorption of nicosulfuron on the surface of PANI@mIF. The maximum adsorption capacity and percent degradation of 87% was achieved with PANI@mIF. Comparatively, good adsorption capacity of PANI@mIF is attributed to a large number of H bonding and electrostatic interactions. Kinetic study indicates the adsorption of nicosulfuron by PANI@mIF followed 2nd order kinetics with R2 of 0.958.The negative values of Gibbs free energy (−18294.3, 19543.1,-7530.4, −7307.7 and −7969.8), enthalpy (−1.97 × 10−4) and entropy (−3.54 × 10−3) indicate spontaneous and exothermic nature of the process. The reusable nature of PANI@mIF with 5 batches reflected its inventive photo catalytic behaviour for real sample applications and waste water treatment.

Magnetic detachable catalyst of Ag-decorated Fe3o4 nanocomposites using agro-waste extracts towards photocatalytic degradation of organic dye and their bactericidal effect

Magnetic detachable catalyst of Ag-decorated Fe3o4 nanocomposites using agro-waste extracts towards photocatalytic degradation of organic dye and their bactericidal effect

Magnetic Field Effect on Photocatalytic Dye Degradation: A Review

AbstractIn the present day, photocatalysis has become the primary and most promising technology to generate renewable energy and degrade environmental pollutants. Remarkable efforts have been made to improve photocatalytic efficiency. Among these, introducing an external magnetic field is considered a promising strategy to boost photocatalytic performance. This review explores the dynamic realm of improving photocatalytic efficiency, with a particular emphasis on the strategic integration of external magnetic fields. Examining recent breakthroughs, we reviewed the influence of magnetic fields on diverse catalyst materials, including both magnetic and nonmagnetic variants, 2D materials, and semiconductors. Comprehensive coverage is provided on the mechanisms governing photocatalytic dye degradation, materials utilized for catalysis, and the profound impact of magnetic fields on enhancing reaction kinetics. This review also focuses on recent advances in the application and effect of magnetic fields in the magnetic and nonmagnetic catalysts towards dye degradation. This review provides a forward‐looking view, highlighting the potential of magnetic field‐enhanced photocatalysis to play a central role in sustainable energy and environmental management.

Enhancing the catalytic H2 production performance of magnetic Ni-Fe2O3-C catalyst in biomass steam gasification using electromagnetic induction heating

In this study, a novel magnetic Ni-Fe2O3-C catalyst combined with electromagnetic induction heating in biomass steam gasification was proposed to enhance H2 production. Better catalytic performance for H2 production was observed with the Ni-Fe2O3-C catalyst under induction heating, resulting in an increase in H2 yield from 735.1 to 2271.2 mL/g-biomass (a 209.1 % enhancement). SEM, TGA and XRD analysis demonstrated a significant decrease in coking deposition, caking, and particle agglomeration of the Ni-Fe2O3-C catalyst under induction heating, while maintaining more active sites. Importantly, the benefits of induction heating were also applicable to different magnetic catalysts like Ni-Al2O3-C, Ni-ZrO2-C, and Ni-MgO-C. Experimental results revealed a logarithmic correlation between the increase in H2 yields due to induction heating and the magnetic saturation (Ms) of the catalysts. The Ni-Fe2O3-C catalyst, with a high Ms of 50.9 emu/g, showed the highest catalytic activity for H2 production under induction heating in this study.

Magnetic Field Enhanced Cobalt Iridium Alloy Catalyst for Acidic Oxygen Evolution Reaction.

Magnetic field mediated magnetic catalysts provide a powerful pathway for accelerating their sluggish kinetics toward the oxygen evolution reaction (OER) but remain great challenges in acidic media. The key obstacle comes from the production of an ordered magnetic domain catalyst in the harsh acidic OER. In this work, we form an induced local magnetic moment in the metallic Ir catalyst via the significant 3d-5d hybridization by introducing cobalt dopants. Interestingly, CoIr nanoclusters (NCs) exhibit an excellent magnetic field enhanced acidic OER activity, with the lowest overpotential of 220 mV at 10 mA cm-2 and s long-term stability of 120 h under a constant magnetic field (vs 260 mV/20 h without a magnetic field). The turnover frequency reaches 7.4 s-1 at 1.5 V (vs RHE), which is 3.0 times higher than that without magnetization. Density functional theory results show that CoIr NCs have a pronounced spin polarization intensity, which is preferable for OER enhancement.

A Synthetic Approach to Synthesize Furan‐2‐Carboxylate Derivatives by Using a Magnetic Sodium Aluminate Catalyst

AbstractA novel and efficient procedure has been developed to synthesize furan‐2‐carboxylate derivatives through a one‐pot condensation of chloroacetate derivatives, 1,3‐diketones, and chloroform in the presence of magnetic sodium aluminate 40 wt. % (Aluminate NP‐40). The synthesized heterogeneous catalyst can be easily recovered from the reaction mixture by applying an external magnetic field. Magnetic aluminate NP catalysts provide a sustainable, environmentally friendly, and cost‐effective method for synthesizing furan‐2‐carboxylate derivatives. Additionally, the catalyst is stable and can be reused multiple times without losing its catalytic properties. High product yields in a short experimental time and easy workup are other advantages of the present method. All synthesized compounds were characterized by NMR spectroscopy.

A copper- and amine-free sonogashira reaction catalyzed by a supported bis(oxime palladacycle) on magnetized SBA-15

The recently reported magnetic catalyst, Fe3O4@SBA-bis(oxime palladacycle), was incorporated in the Sonogashira reaction. The potential catalytic activity of the catalyst was evaluated by optimizing the reaction conditions. It was discovered that using dimethylsulfoxide (DMSO) as a solvent, a catalyst loading of 0.25 mol% palladium, Cs2CO3 as a base, and a reaction temperature of 120 °C resulted in the highest yields. The catalyst showed excellent activity with a wide range of aryl halides and aryl acetylenes in the Sonogashira reaction. The use of a low catalyst loading further highlighted its efficiency. Moreover, the catalyst demonstrated noteworthy reusability by consistently preserving its activity and stability through seven successive runs. The magnetic properties of the catalyst allowed for easy separation and recovery.

Assessing the application of a biochar-supported iron oxide catalyst to the treatment of imidacloprid by photo-Fenton technologies

Emerging contaminants entail a great challenge to conventional treatment systems because they are not able to remove most of these bio-recalcitrant compounds. In particular, the presence of pesticides, such as imidacloprid, in the environment is a great hazard to soil microbiota, pollinating insects, and the aquatic environment. This research aims to enhance the treatment efficiency of advanced oxidation processes applied to the removal of bio-recalcitrant pollutants that are present in stormwater by assessing the application of a newly designed, economical, and efficient treatment alternative. Specifically, solar and LED (365 and 420 nm) heterogeneous photo-Fenton processes were carried out to remove a concentration of 5 mg·L−1 of imidacloprid, which was selected as the model pollutant that has been identified present in stormwater, using a magnetic iron oxides catalyst supported on pinewood waste biochar. The removal kinetics and mineralization of this contaminant were determined under the effect of the natural pH value of the solution and under a circumneutral pH environment, and heterogeneous and homogeneous catalytic contributions to the process were assessed. All these treatments achieved the successful efficient removal of the contaminant whether applying LED (UVA or visible blue) or solar radiation. The heterogeneous photo-Fenton treatment using a magnetic iron oxide catalyst supported on pinewood waste biochar totally removed imidacloprid after 10 minutes of oxidation at the initial natural pH value of the solution using 365 nm UVA LED radiation. Moreover, a 70% TOC removal was addressed after 60 minutes of treatment. The solar version of this heterogeneous photo-Fenton process removed the contaminant after 60 minutes of reaction, together to a TOC removal of the 60–65% after 120 minutes of treatment, including certain photolytic contribution; as well as it showed very efficient results under the effect of a circumneutral pH value. The assessed biochar-supported iron oxide catalyst was displayed as very stable under all the tested reaction conditions and its heterogeneous contribution to the process was confirmed superior to an exclusive homogeneous process.

Preparation of Cs/CuAl-LDO@Al2O3@Fe3O4 magnetic catalysts and reaction mechanism of the side-chain alkylation of toluene to styrene

A series of Cs/CuAl-LDO@Al2O3@Fe3O4 magnetic catalysts with varied CuAl-LDO contents were prepared by growing CuAl-LDH layers on the surface of Al2O3@Fe3O4 magnetic cores, impregnated with Cs and followed by calcination. The as-synthesized catalysts were characterized by XRD, N2 adsorption-desorption, SEM, TEM(EDS), XPS, NH3-TPD, CO2-TPD, and VSM techniques. The catalytic performance and reusability of the catalysts for the side-chain alkylation of toluene with formaldehyde were evaluated in a micro-high-pressure reactor, and the reaction mechanism was further studied. The results showed that the Al2O3@Fe3O4 magnetic core of the catalyst was about 110 nm, and the CuAl-LDO formed a staggered lamellar structure with a shell thickness of around 30–45 nm. The magnetic catalyst demonstrated excellent catalytic performance and reusability for the side-chain alkylation of toluene with formaldehyde in one-step to styrene. As-synthesized magnetic Cs/CuAl-LDO@Al2O3@Fe3O4 catalyst with CuAl-LDO content of 20 wt% delivered toluene conversion of 7.97% under optimized conditions, while the styrene selectivity and the selectivity of side-chain alkylation were 90.17% and 98.36%, respectively. The reaction mechanism showed that the benzene ring of toluene was stably adsorbed on the Al3+ acid sites of the CuAl-LDO layers. The C–H group of the side-chain of toluene formed carboanions and protons under the action of the Cuδ+–Oδ– base sites. Formaldehyde formed a transition state of adsorbed formaldehyde under the action of Cuδ+ acid sites. Finally, these adsorbed states and intermediate species accomplished the side-chain alkylation of toluene with formaldehyde to styrene in one-step under the synergic action of acid-base sites. The synergistic effects of suitable acid-base sites and lamellar spatial structures in the catalyst were the key to styrene formation with high selectivity.

Metal-organic frameworks (MOFs) wrapped palladium nanoparticles-loaded Fe3O4@CFR core-shell magnetic nanohybrid as heterogeneous catalyst with robust catalytic properties

Metal-organic frameworks (MOFs) wrapped palladium nanoparticles supported on Fe3O4@catechol formaldehyde resin (Fe3O4@CFR@Pd@MOF) as magnetic nanohybrid catalyst was successfully fabricated by employing the redox capacity of CFR shell of Fe3O4@CFR core-shell microsphere for in situ formation of Pd NPs, followed by surface coating with Cu-MOF(HKUST-1). The research results demonstrated that the complementary properties of the various components within this hybrid material yielded magnetic recyclable nanocatalysts with exceptional catalytic performance. The Fe3O4@CFR@Pd@MOF catalyst exhibited remarkable advantages in the catalytic reduction of nitrophenol, demonstrating a transformation frequency (TOF) value of up to 4651 h−1. Additionally, the nanocatalyst was proved to have robust catalytic capacity in the reduction of organic dyes and Suzuki-Miyaura reaction. The HKUST-1 framework played a triple role: facilitating dye enrichment, Cu2+ assisting Pd NPs catalysis, and mitigating Pd NPs leaching. Moreover, the synthesized catalyst exhibited favorable magnetic properties, enabling facile separation by magnets for efficient recycling and reutilization.

Synthesis and density functional theory study of functionalized Oxazolidine-2-ones using a novel MnFe2O4@SiO2-SiO3H magnetic nanocatalyst

This study introduces MnFe2O4@SiO2-SiO3H as a novel magnetic catalyst and thoroughly investigates its structure, catalytic activity, and reusability. The synthesis of the magnetic catalyst was meticulously characterized using an array of analytical techniques. Utilizing MnFe2O4@SiO2-SiO3H, the synthesis of functionalized oxazolidine-2-ones were performed, versatile compounds widely employed in chiral auxiliaries, protecting groups, and medicinal chemistry. Remarkably, the two-step process from chalcones demonstrated one of the shortest reported pathways, highlighting the efficiency of our novel nanocatalyst. To elucidate the stability and reactivity of the synthesized products, we employed Density Functional Theory (DFT) calculations, including molecular electrostatic potential (MEP) mapping and reactivity indices such as electronegativity, electrophilic index, softness, and hardness, as well as frontier molecular orbitals (HOMO-LUMO). Furthermore, our investigations extended to the recycling capabilities of the nanocatalyst. Through a comprehensive evaluation of at least five reaction cycles, MnFe2O4@SiO2-SiO3H showcased a remarkable retention of activity (97–92 %), reaffirming its reusability and long-term potential. Our research presents MnFe2O4@SiO2-SiO3H as a highly effective and recoverable nanomagnetic catalyst for organic reactions, with demonstrated applications in synthesizing functionalized oxazolidine-2-ones. As such, our findings offer a promising alternative to traditional methods, presenting new opportunities in catalysis and materials science.

Facile synthesis of Fe3O4@biochar@SO3H as magnetically separable Bronsted acid nanocatalyst for biodiesel production from different oil feedstocks

A novel magnetically separable Fe3O4@biochar@SO3H catalyst was developed from mesua assamica (King & prain) waste seed shells biochar for cost-effective biodiesel production using novel mesua assamica seed oil, jatropha oil, and soybean oil. The magnetic solid acid catalyst was synthesized via impregnation of biochar with Fe3O4 magnetic nanoparticles followed by sulfonation techniques. Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) analysis suggested the successful sulfonation and existence of –SO3H groups on catalyst surface. The synthesized magnetic acidic catalyst possesses total acidity of 3.9 mmol g−1 and –SO3H density of 1.8 mmol g−1. The field emission transmission electron microscopy (FETEM) led core-shell structured catalyst particle demonstrated a mean size of 87.4 nm and the surface area of 71.47 m2 g−1. The acidic catalyst easily afforded maximum yield of 96.8% mesua assamica biodiesel, 95.3% jatropha biodiesel, and 95.8% soybean biodiesel under optimized reaction parameters. The kinetic investigation suggested the occurrence of pseudo first order kinetics with activation energy of 32.42 kJ mol−1. The magnetically separable catalyst also displayed promising activity and stability up to 3rd cycle with more than 75% biodiesel yield.