Iron Nanocatalysts Research Articles

Polarity Modulation Enhances Electrocatalytic Reduction of Nitrate by Iron Nanocatalysts

Polarity Modulation Enhances Electrocatalytic Reduction of Nitrate by Iron Nanocatalysts

Recent Advances in Solvent-free Organic Transformation via Iron-doped Nanocatalyst

Abstract: This article highlights current developments in iron-doped nanocatalyst-based solvent-free organic reactions. These catalysts have the potential to speed up processes under safe environmental settings and eliminate the need for hazardous organic solvents. Its application in a variety of fields is mostly due to its superparamagnetic nano diameters, which are affordable, easily separable, reusable, and eco-friendly. Thus, the present review article focuses on the compendious account of various doped iron nanocatalysts reported catalyzing organic transformation, including synthesis of bioactive compounds, condensation, multicomponent, annulation, esterification, coupling, alkylation, acylation reactions. The development of innovative, highly active, and reusable magnetic iron nanocomposite catalysts is crucial for the future of catalysis as it will pave the way for the creation of environmentally friendly and sustainable technology. The review will provide valuable insights for researchers who are designing new functionalized doped iron catalysts or utilizing these catalysts for various organic transformations that promote sustainable development. The development of new precursors and synthesis techniques, as well as recent improvements in the synthesis of these catalysts, are described. The article also emphasizes the significance of comprehending the underlying processes of these catalytic events, as well as the difficulties and possibilities for further study in this field. The potential of iron-doped nanocatalysts as an environmentally friendly and long-lasting method of organic synthesis is emphasized throughout this review.

Wearable electrochemical patch based on iron nano-catalysts incorporated laser-induced graphene for sweat metabolites detection

The development of wearable devices shows great application potential in health management. In this work, we propose the fabrication of a novel wearable electrochemical patch and prove its application in sweat metabolites detection. The patch is developed based on iron nano-catalysts incorporated laser-induced graphene (FeNCs/LIG), which is a newly integrated sensing electrode with unique three-dimensional nanostructure and good electrocatalytic activity. It shows desirable sensing performances for sweat metabolites including tyrosine (Tyr) and uric acid (UA) molecules. The detection limit of Tyr and UA can reach 5.11 μM and 1.37 μM, respectively. Besides, density functional theory calculation deeply reveals that the Fe active sites of FeNCs play an important role in molecule adsorption and electron transference, thus promoting sensing performance. To realize wearable application, a dual-channel hydrogel chip is designed and assembled with FeNCs/LIG. The developed patch is successfully utilized to accurately determination of Tyr and UA in sweat. This work is expected to provide a new non-invasive strategy for evaluating amino acid intake and metabolic level.

Low-Palladium-Content Iron(III) Nanocatalyst Supported on Zeolite-NaY for C–Cl Bond Activation

Low-Palladium-Content Iron(III) Nanocatalyst Supported on Zeolite-NaY for C–Cl Bond Activation

Synthesis of plant-based biogenic jarosite nanoparticles using Azadirachta indica and Eucalyptus gunni leaf extracts and its application in Fenton degradation of dicamba

Bio-jarosite, an iron mineral synthesized biologically using bacteria, is a substitute for iron catalysts in the Fenton oxidation of organic pollutants. Iron nanocatalysts have been widely used as Fenton catalysts because they have a larger surface area than ordinary catalysts, are highly recyclable, and can be treated efficiently. This study aimed to explore the catalytic properties of bio-jarosite iron nanoparticles synthesized with green methods using two distinct plant species: Azadirachta indica and Eucalyptus gunni. The focus was on the degradation of dicamba via Fenton oxidation. The synthesized nanoparticles exhibited different particle size, shape, surface area, and chemical composition characteristics. Both particles were effective in removing dicamba, with removal efficiencies of 96.8% for A. indica bio-jarosite iron nanoparticles (ABFeNPs) and 93.0% for E. gunni bio-jarosite iron nanoparticles (EBFeNPs) within 120 min of treatment. Increasing the catalyst dosage by 0.1 g/L resulted in 7.6% and 43.0% increases in the dicamba removal efficiency for EBFeNPs and ABFeNPs with rate constants of 0.025 min−1 and 0.023 min−1, respectively, confirming their catalytic roles. Additionally, the high efficiency of both catalysts was demonstrated through five consecutive cycles of linear pseudo-first-order Fenton oxidation reactions.

Sustainable green biogas production from pretreated wheat straw blended with coffee husk using neem leaves-based iron (III) nanocatalyst via response surface methodology

Sustainable green biogas production from pretreated wheat straw blended with coffee husk using neem leaves-based iron (III) nanocatalyst via response surface methodology

Amoxicillin degradation by iron photonanocatalyst synthetized by green route using pumpkin (Tetsukabuto) peel extract

Amoxicillin is a pharmaceutical compound that is not degraded in wastewater treatment plants, causing harm to the environment. In this work, an iron nanoparticle (IPP) was synthesized using pumpkin (Tetsukabuto) peel extract for the degradation of amoxicillin under UV light. The IPP was characterized using scanning electron microscopy/energy dispersive x-ray spectroscopy, transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetric analysis, and Raman spectroscopy techniques. The photocatalytic efficiency of IPP was analyzed by investigating the effect of IPP dosage (1–3 g L−1), initial amoxicillin concentration (10–40 mg L−1), pH (3–9), reaction time (10–60 min), and the effect of inorganic ions (1 g L−1). The optimum conditions for the maximum photodegradation removal (≈60%) were IPP = 2.5 g L−1, initial amoxicillin concentration = 10 mg L−1, pH = 5.6, and irradiation time = 60 min. The results of this study showed that inorganic ions (Mg2+, Zn2+, and Ca2+) negatively affect the photodegradation of amoxicillin by IPP; the quenching test showed that hydroxyl radical (OH•) is the primary reactive species of the reaction; NMR analysis revealed changes in amoxicillin molecules after photoreaction; the subproducts of photodegradation were identified by LC-MS; the proposed kinetic model demonstrated good applicability, predicting the behavior of OH• and determining the kinetic constant, and the cost analysis based on required energy (238.5 kWh m−3 order−1) indicated that the amoxicillin degradation method by IPP is economically viable. This study developed a new efficient iron nanocatalyst for the removal of antibiotics from aqueous environments and provided optimal conditions and relevant information in the area of advanced oxidative processes.

A comprehensive review on synthesis of dihydropyrimidione via Biginelli reaction catalyzed by reusable magnetic nanocatalyst (from 2020–till date)

The discovery of a new class of heterocyclic compounds by Pietro Biginelli in 1891 was regarded as a watershed point in the history of chemistry. Biginelli is a well‐known organic chemistry technique for generating dihydropyrimidones/thiones, which are important biological compounds. The chemistry of the Biginelli motifs has been studied in drug development because of the extensive use of multiple Biginelli adducts in various domains. The current review focuses on the magnetic reusable iron nanocatalysts, imparting their catalytic role in the Biginelli reaction, which can be impregnated with ionic liquids, Lewis's acids, metal (monometallic or bimetallic), or hybrid polymers as catalyst support. Our ongoing interest in developing environmentally friendly synthetic methodologies prompted us to investigate the utility of magnetically reusable catalysts where workup provides an eco‐friendly approach in comparison with traditional methods to provide a clear understanding of pathways leading to the formation of Biginelli adducts.

Preparation and characterization of bimetallic zero-valent iron nanocatalysts for nitrophenol degradation

Backgroundp-Nitrophenol (4-NP) is an organic pollutant found in wastewater discharged from agricultural facilities worldwide. This pollutant is considered as hazardous and toxic by the US Environmental Protection Agency (USEPA). MethodsThe spherical chain-shaped nanophase zero-valent-iron (nZVI) with different metal (Ag, Cr, Cu) loadings was used for wastewater simulation to form bimetallic nanocatalyst (BNC). Moreover, the nZVI and BNC was synthesized and characterized for 4-NP removal. The as-synthesized nZVI and BNCs were used to degrade 4-NP in wastewater, where a higher conversion of 4-NP to aminophenol (4-AP) was observed. The core-shell shape of nZVI@Cu BNCs was also investigated with small angle X-ray scattering (SAXS) to demonstrate the parameters of core-shell model in SAS View. Significant findingsExperimentally, the Cu removal efficiencies at different loading ratios were nZVI@Cu-800> nZVI@Cu-400> nZVI@Cu-200> nZVI@Cu-100. The thermal induced aggregations of nZVI were demonstrated with SAXS, where the 55 °C group displayed 181% increase in size when compared with the 25 °C group. The XANES/EXAFS spectra revealed the presence of Cu2O in nZVI@Cu, a phenomenon which provided the reductive degradation mechanism of the chemical reactions. In this study, heavy metal absorbed onto nZVI and BNCs reduced 4-NP heavy metal contaminants to less toxic 4-AP. Thus, the as-synthesized nZVIs could effectively convert harmful 4-NP in wastewater into useful and high-value 4-AP by-products.

Surface engineering of carbon fiber via upcycling of waste gases generated during carbon fiber production: A sustainable approach towards high-performance composites

Carbon fiber (CF) prevails as a cutting-edge material, however, considerable waste gases produced in its production place a tremendous burden on the industry and environment. Our previous study proposed a “two-birds-one-stone” strategy to simultaneously convert the gaseous effluents into carbon nanotubes (CNT) and produce multifunctional CNT@CF materials. However, the challenges in the management of iron nanocatalysts and the containment of side effects on the performance of CF composites have significantly affected the scalability of this technique. In the present work, we developed a further comprehensive understanding of cobalt and nickel-based metallic CFs as new catalysts to obtain more controlled and effective catalytic properties and subsequently extend the better performance of CF composite. In-situ capture and solidification of gases generated from the carbonization step of CF production process created more novel CNTs in the tip- and base-growth model. The CNTs with tip-growth model exhibited a better enhancement effect than the base-growth model on the interfacial properties of composites with up to 57% and 54% improvement in interfacial and inter-laminar shear strength, respectively. Moreover, new insights regarding the evolution mechanism of CNTs were provided through qualitative and quantitative analysis of the gas emissions reduction and recycling efficiency, supported by density functional theory. In this work, more available practical parameters governing the catalytic properties of metallic CF provide additional efficiency of gas waste recovery, diversity of CNTs, and potential for emerging applications, which delivers a more comprehensive guarantee for the implementation of this technology on the CF production line in the next step.

Magnetic confinement-enabled membrane reactor for enhanced removal of wide-spectrum contaminants in water: Proof of concept, synergistic decontamination mechanisms, and sustained treatment performance

Membrane chemical reactors (MCRs) have demonstrated a great potential for simultaneous removal of wide-spectrum pollutants in advanced water treatment. However, current catalyst (re)loading and catalytic reactivity limitations obstruct their practical applications. Herein, as a proof-of-concept, we report a hollow fiber membrane chemical reactor (HF-MCR) with high and sustainable catalytic reactivity, enabled by novel magnetic confinement engineering of the catalysts. Namely, the zerovalent iron (ZVI) nanocatalysts were spatially dispersed and confined to nearly parallel magnetic induction lines, forming forest-like microwire arrays in the membrane lumen. Such arrays exhibited ultrahigh hydrodynamic stability. The HF-MCR integrated sequential membrane separation and Fenton-like catalysis, thus being capable of high and synergistic wide-spectrum decontamination. The membrane separation process completely removed large nanoplastics (NPs) via size exclusion, and thus the subsequent Fenton-like catalysis process enhanced removal efficiency of otherwise permeated bisphenol A (BPA) and phosphate (P) by in situ generated reactive oxygen species (primarily 1O2) and iron (oxyhydr)oxides, respectively. Furthermore, highly dispersed ZVI arrays and their continuous surface depassivation driven by magnetic gradient and hydrodynamic forces conferred abundant accessible catalytic sites (i.e., Fe0 and FeII) to stimulate Fenton-like catalysis. The consequent enhancement of BPA and P removal kinetics was 3–765 and 49–492 folds those in conventional (flow-through or batch) systems, respectively. Periodic ZVI reloading ensured sustained decontamination performance of the HF-MCR. This is the first demonstration of the magnetic confinement engineering that enables efficient and unlimited catalyst (re)loading and sustainable catalytic reactivity in the MCR for water treatment, which is beyond the reach of current approaches.

Lignin Residue-Derived Carbon-Supported Nanoscale Iron Catalyst for the Selective Hydrogenation of Nitroarenes and Aromatic Aldehydes.

Heterogeneous iron-based catalysts governing selectivity for the reduction of nitroarenes and aldehydes have received tremendous attention in the arena of catalysis, but relatively less success has been achieved. Herein, we report a green strategy for the facile synthesis of a lignin residue-derived carbon-supported magnetic iron (γ-Fe2O3/LRC-700) nanocatalyst. This active nanocatalyst exhibits excellent activity and selectivity for the hydrogenation of nitroarenes to anilines, including pharmaceuticals (e.g., flutamide and nimesulide). Challenging and reducible functionalities such as halogens (e.g., chloro, iodo, and fluoro) and ketone, ester, and amide groups were tolerated. Moreover, biomass-derived aldehyde (e.g., furfural) and other aromatic aldehydes were also effective for the hydrogenation process, often useful in biomedical sciences and other important areas. Before and after the reaction, the γ-Fe2O3/LRC-700 nanocatalyst was thoroughly characterized by X-ray diffraction (XRD), N2 adsorption–desorption, X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HR-TEM), Raman spectroscopy, and thermogravimetric analysis (TGA). Additionally, the γ-Fe2O3/LRC-700 nanocatalyst is stable and easily separated using an external magnet and recycled up to five cycles with no substantial drop in the activity. Eventually, sustainable and green credentials for the hydrogenation reactions of 4-nitrobenzamide to 4-aminobenzamide and benzaldehyde to benzyl alcohol were assessed with the help of the CHEM21 green metrics toolkit.

One-step preparation of char-supported iron nanocatalysts under microwave irradiation and their application for tar removal

Char-supported iron nanocatalysts were synthesized directly by one-step microwave pyrolysis of iron salt impregnated sawdust and applied to cracking of biomass tar model compound (naphthalene). The catalysts prepared by three pretreatment methods were evaluated comparatively. The nanocatalysts with well-dispersed Fe particles (average particle size ≤ 11.3 nm) immobilized on the carbon support were obtained with ultrasonic pretreatment and hydrothermal pretreatment. The X-ray photoelectron spectroscopy (XPS) results indicated that more metallic iron and ferrous iron formed at 750 °C (NWC750) than that at 500 °C (NWC500). The catalysts synthesized with ultrasonic pretreatment (USC750) and hydrothermal pretreatment (HTC750) exhibited excellent catalytic activity at a high space velocity with high tar conversion efficiency (~100.0%) as well as good catalytic stability at 750 °C/4 h. And spent HTC750 displayed high resistance towards coke deposition (0.004 gcokegCat−1h−1). Meanwhile, a possible evolutionary process of Fe nanoparticles on the carbon support during microwave pyrolysis was proposed.

α-Hydroxy acids modified β-cyclodextrin capped iron nanocatalyst for rapid reduction of nitroaromatics: A sonochemical approach

This study reports a sonochemical approach for the synthesis and catalytic performance of zerovalent iron nanoparticles (nZVI) capped with two cyclodextrin (CD) crosslinked polymers derived from Lactic acid and Citric acid (CDLA and CDCA respectively). The polymers and the catalysts were characterized by NMR, FTIR, HRTEM, DLS, Zeta potential, FESEM, EDAX, VSM, XRD, XPS, TGA analysis. The catalysts proved to be sustainable and recyclable for rapid sonochemical reduction of nitroaromatics under ambient conditions. The isolated yield of the derivatives was found to be greater than 90%. The results suggest excellent dispersibility, stability, high iron content and smaller size of CDLA polymer capped nZVI compared to CDCA capped nZVI, leading to two-fold higher catalytic activity. The effect of various crucial catalysis parameters was investigated and optimized. The scope of the reaction was extended to other nitroaromatics under the optimized conditions. Being magnetically separable, the cost effective and non-toxic catalysts exhibited high recycling efficiency (~13 cycles), high turnover number (TON) and turnover frequency (TOF). The recyclable catalysts could be low-cost and sustainable options for organic transformation in water via sonochemical approach in aqueous medium.

Ionic Liquid Co-Catalyst Assisted Biodiesel Production From Waste Cooking Oil Using Heterogeneous Nanocatalyst: Optimization and Characterization

In the present work, the biodiesel was produced from waste cooking oil (WCO) using heterogeneous zinc doped iron nanocatalyst and tetrabutylammonium iodide (TBAI) as co-catalyst. The heterogeneous zinc doped iron nanocatalyst was synthesized and characterized. The functional group in the heterogeneous nanocatalyst was confirmed using FTIR analysis, the crystalline nature was studied by XRD analysis, and the size and structure of the nanocatalyst were analyzed by SEM. The optimization of transesterification parameters like oil to methanol molar ratio, zinc doped iron concentration, TBAI concentration, temperature, and time were carried out for the maximum conversion of biodiesel from WCO. At 50 min the maximum biodiesel conversion of 90% was achieved at 55°C with 12% catalyst, 30% co-catalyst, and 1:11 WCO to methanol ratio. The presence of functional groups and the methyl ester composition of the biodiesel from WCO were confirmed by FTIR and GC-MS analysis. The use of zinc doped iron nanocatalyst with TBAI showed good catalytic activity to produce biodiesel from WCO.

Metallic Iron Nanocatalysts for the Selective Acetylene Hydrogenation under Industrial Front-End Conditions

Metallic Iron Nanocatalysts for the Selective Acetylene Hydrogenation under Industrial Front-End Conditions

Multiwalled carbon nanotubes grown over green iron nanocatalyst as electrode for hydrogen-producing electrochemical cell

Multiwalled carbon nanotubes grown over green iron nanocatalyst as electrode for hydrogen-producing electrochemical cell

Synthesis of Co-Fe nanoparticle supported on titanium oxide-nanotubes (TiO2-NTs) as enhanced oxygen reduction reaction electrocatalyst

The performance of electrocatalyst is usually limited owing to the slow electron transfer kinetics of cathode reduction reaction. Therefore, the development of high-performance cathode catalysts has an impact on the wide-spread application of fuel cells. The improvement of appropriate doping approaches is important to achieve high-performance electrocatalytic resources. Herein, a series of Co-Fe @ TiO2-NTs electrocatalytic composites were synthesized by doping various amounts of metals. The synthesis, physiochemical and electrocatalytic activity of cobalt (Co) and iron (Fe) nanocatalysts supported on one dimensional (1-D) titanium oxide-nanotubes (TiO2-NTs) matrix towards oxygen reduction reaction was reported. The Co-Fe nanoparticles confined in TiO2 nanotube were produced as the oxygen reduction electrocatalyst by hydrothermal and reduction method. Electrochemical tests showed that the reduction peak current of −0.305 mA was recorded for catalyst Co-Fe (7:3) @ TiO2-NTs and was observed to be 1.50 times superior to that for the catalyst commercial catalyst Pt/C (-0.202 mA). The electrochemical characterizations of these nanocatalysts also suggest that the Co-Fe (7:3) @ TiO2-NTs showed lower charge transfer resistance (109.4 Ω) in comparison to Pt/C (350.4 Ω) towards oxygen reduction reactions (ORR). These superior electrochemical results suggested that Co-Fe nanoparticle supported on titanium oxide-nanotubes (TiO2-NTs) could be applied as a potential alternative to the commercial Pt/C cathode catalyst for their application as oxygen reduction reaction (ORR) electrocatalyst in a neutral medium.

Enhanced biogas from sewage sludge digestion using iron nanocatalyst from Vitex negundo leaf extract: response surface modeling

In this study, Vitex negundo leaf extract (VN) were utilized as a potential reducing agent to enable greener synthesis of iron nanocatalyst (VN-FeNCs). The synthesis time and ratio of extract to precursor and pH of extract for green synthesis of VN-FeNCs were optimized. Furthermore, the synthesized VN-FeNCs were characterized for morphological, functional and spectral properties. VN-FeNCs were supplemented for the anaerobic digestion of the sludge. Augmentation of VN-FeNCs improvised the methane yield with reduction of chemical oxygen demand up to 86% and volatile solids up to 93.6% with a retention time of 12 days. The highest biogas yield of 0.45 (L/g VS reduced) is obtained with VN-FeNCs aided digestion whereas digestion with bulk salt and control yielded 0.13 (L/g VS reduced) and 0.07 (L/g VS reduced) respectively. The central composite matrix under the response surface optimization was employed to estimate the optimal process conditions, and the outcome reveals that reactions when maintained at pH 7.0 with 0.2 g/L of VN-FeNCs escalated good biogas production on 6th day. Conclusively, the remarkable reduction in the digestion time would contribute to increase the life span of biogas digester and will reduce the overall maintenance cost.

Super-Strong Carbon Nanotube Fibers Achieved by Engineering Gas Flow and Postsynthesis Treatment.

Carbon nanotube fibers (CNTFs) are directly spun from a floating-catalyst chemical vapor deposition apparatus using gas-phase carbon and an iron nanocatalyst. The essential synthesis and post-treatment factors that affect the strength of CNTFs are investigated to obtain CNTFs with greater strength than those of any previously reported high-performance fibers. The key factors optimized included the degree of rotational flow inside the reactor, the ratio of the starting materials, and the postsynthesis treatment conditions. The formation of rotational gas flow inside the reactor was confirmed by computational fluid dynamics simulations, and the feed ratio of the starting materials was optimized through response surface methodology. In addition, a reproducible and highly efficient postsynthesis treatment method was established. Pristine CNTFs with a high specific strength (SS) (average 2.2 N/tex, max. 2.3 N/tex) were synthesized through decreased rotational flow and optimization of the CNTF synthesis conditions. To improve the SS of the CNTFs further, we adopted an acid wet-stretching method that included washing and heat treatment. This drastically increased the SS of the CNTFs (average 5.5 N/tex, max. 6.4 N/tex) because of the decrease in the volume of the pores between the CNT bundles.