Fe-Ni Bimetallic Nanoparticles Research Articles

NixFe100-x for urea and oxygen evolution: a matter of compromise

The combination of aqueous electrolysis, either for hydrogen generation or CO2 conversion, with wastewater treatment offers an elegant way to tackle issues associated with our energy transition and the need for clean drinking water. However, it requires an anode capable of doing both the oxidation of the targeted pollutant and the oxygen evolution reaction (OER), as most pollutants are present in too low concentration to be practical for industrial electrolysis. In this study, we focussed on the oxidation of urea on NixFe100-x catalysts. These catalysts were prepared by pulsed laser ablation in liquid, a versatile and green technique to prepare electrocatalysts. Transmission electron microscopy of the nanoparticles indicates the production of monodisperse nanoparticles, with an average diameter increasing from 7.8 ± 2.8 to 19.7 ± 3.9 nm with a higher iron fraction. The composition could be controlled between pure Ni and NiFe bimetallic nanoparticles with up to 56 ± 3% of iron, by controlling the composition of the target. A brief optimisation of the electrode preparation (loading, catalyst-to-carbon ratio) yielded an optimum at about 30 µg/cm2 of catalyst with a catalyst-to-carbon ratio of 20:80. During the electrocatalytic tests, Ni was the best catalyst for urea oxidation, with a maximum peak current of 619 mA/mg. However, Ni75Fe25 was the best OER catalyst, showing a peak current of 1150 mA/mg. The difference increased further during CA at 0.5 V, during which Ni75Fe25 outperformed pure Ni by almost a factor of 3 after 30 min.

Flower-like L-Cys-FeNiNPs nanozyme aptasensor for sensitive colorimetric detection of aflatoxin B1

It is vital to create a sensitive and trustworthy sensor for aflatoxin B1 (AFB1) considering the potential hazards this substance poses to the safety of food. Herein, a colorimetric sensor, namely, aptamer-modified flower-like L-cysteine-functionalized FeNi bimetallic nanoparticles (L-Cys-FeNiNPs) with peroxidase-mimicking enzymatic activity, was established for the detection of aflatoxin B1. Interestingly, based on the synergies between FeNi bimetals and the protection and regulation of morphology by L-Cys on FeNiNPs, we successfully synthesized flower-like L-Cys-FeNiNPs, which were employed as outstanding peroxidase-mimic enzymes to oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H2O2. Kinetic analysis showed that the flower-like L-Cys-FeNiNPs have an ultralow Michaelis constant (Km) and an ultrahigh affinity for H2O2. Furthermore, based on the peroxidase-mimicking activity of flower-like L-Cys-FeNiNPs, a new colorimetric aptamer sensing strategy was employed for the easy and specific detection of AFB1 with a wide response range (0.12–2 μg/mL) and a low detection limit (36.57 ng/mL). Finally, to verify the practicality of this aptamer detection strategy, we successfully applied it to the detection of AFB1 in actual millet and maize samples.

Fe-Ni bimetallic nanoparticles encapsulated into nanofibrous carbon microspheres as a catalytic nanoreactor for highly selective hydrogenation of 5-hydroxymethylfurfural to 2,5-dihydroxymethylfuran or 2,5-dihydroxymethyltetrahydrofuran

BackgroundThe highly efficient conversion of renewable biomass-derived platform compounds to high value-added chemicals is one of the most promising solution to the current rapid consumption of fossil resources. MethodsNanofibrous and porous carbon microspheres (NPCMs) were developed from chitin biomass and used to encapsulate Fe-Ni bimetallic nanoparticles for the formation of a novel catalytic nanoreactor (Fe-Ni/NPCMs), which was then used for the selective hydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-dihydroxymethylfuran (DHMF) or 2,5-dihydroxymethyltetrahydrofuran (DHMTHF). Significant findingsThe NPCMs consisted of N-doped carbon nanofibers with a high surface area. The Fe-Ni bimetallic nanoparticles were uniformly dispersed on the carbon nanofiber surfaces of the Fe-Ni/NPCMs, resulting in abundant catalytic sites and excellent catalytic performance. Importantly, the Fe-Ni/NPCMs showed highly-selective hydrogenation of HMF to DHMF or DHMTHF with high yields of 93.6% or 94.9% through simply modulating the reaction conditions. Increasing the zero valent iron (Fe0) content in the Fe-Ni/NPCMs significantly promoted the DHMTH selectivity from HMF hydrogenation. Moreover, the Fe-Ni/NPCMs presented high stability and recyclability, and thus they are applicable to other biomass conversions. Therefore, Fe-Ni/NPCMs have promising industrial application in the production of high value-added chemicals from biomass-derived feed-stocks.

BIOSSENSOR PARA NÍVEL DE INSULINA SANGUÍNEO EM ATLETAS

ABSTRACT Introduction: The pancreas releases insulin to assist the human body in utilizing blood glucose. It regulates metabolism by promoting the absorption of glucose into the blood. Objective: This work aimed to create an electrochemical biosensor based on magnetic graphene nanomaterial to measure insulin levels in athletes’ blood. Method: A magnetic graphene nanocomposite created by graphene oxide (GO) and Fe-Ni bimetallic oxides on a glassy carbon electrode was synthesized using the electrochemical deposition method (GCE). Results: The immediate electrical deposition of Fe-Ni bimetallic oxide nanoparticles with the spherical shape on the GO nanosheet without aggregations was validated by structural characterizations of Fe-Ni/GO/GCE using XRD and SEM. The electrochemical results for insulin determination showed good sensitivity and anti-interference capability. The applicability and accuracy of the proposed electrochemical sensor to detect insulin were explored by blood serum samples from sportsmen. Conclusion: The results assigned acceptable RSD values (3.31% to 4.30%) and confirmed the feasibility of the proposed sensor for detecting athletes’ blood insulin. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

Reuse of Bimetallic Nanoparticles for Nitrate Reduction

The aim of this research is investigation of FeNi bimetallic nanoparticles effectiveness after their using in the reduction of the high nitrate concentration. The advantage of the reusability is opportunity to create cost effective and environmentally friendly technologies. In this paper the efficiency of the same bimetallic nanoparticles was described. The same nanoparticles were used for nitrate reduction in the first, second and third times. After each use they were collected and used again for reduction of 300 mg L <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> nitrates. Fe/Ni based bimetallic nanoparticles were synthesized freshly and used for nitrate removal. Synthesis of bimetallic nanoparticles was carried out in the presence of sodium oleate as dispersing agent by widely known borohydride reduction method. Batch experiments were performed on nitrate contaminated water samples. The parameters investigated were the reaction pH (acidic, alkaline conditions) and nitrates concentration after their reusing. The results showed that the total nitrate reduction (99.75%) was occurred after 5 min of reaction in the presence of freshly synthesized nanoparticles. Then the same nanoparticles were repeatedly used for nitrate reduction. This test has been performed thrice to study nanoparticles effectiveness after each use. It was investigated that the efficiency of nitrate degradation decreased after reusing. The second remediation by the same nanoparticles consisted 64.67% of nitrates removal and the third one – 47%. To evaluate the nitrate reduction rate and the kinetic of reaction, additional tests were performed at different temperatures. The structural characterization of freshly synthesized and reused bimetallic nanoparticles was investigated by TEM. Results showed that bimetallic nanoparticles were covered with an oxide layer after nitrates reduction. Decreased efficiency of reused bimetallic nanoparticles can be due to the appearance of an oxide layer.

Bimetallic FeNi Alloy Nanoparticles Grown on Graphene for Efficient Removal of Congo Red From Aqueous Solution

AbstractNano zero‐valent iron (nZVI) is an effective material for dye wastewater treatment, but excessive agglomeration and oxidation greatly limit its application. Herein, graphene (GR) supported FeNi bimetallic nanoparticles (FeNi@GR) are prepared by alloying and carrier supported dispersion for efficient removal of azo dyes from water. Not only can it effectively solve the problem of excessive agglomeration and oxidation of nZVI, but also the synergistic effect of bimetallic coordination formation and the excellent electron transfer ability of graphene are beneficial to enhance the reactivity of FeNi@GR. The optimal FeNi@GR is prepared by adjusting the content of GR and the removal of Congo red (CR) by FeNi@GR‐10% reached 625 mg g−1 within 150 min at pH = 7.0. Higher temperature and lower pH favor the removal of CR azo dye. The action mechanisms of FeNi@GR presumably involve the transfer of active hydrogen atoms and the transfer of electrons generated by Fe0 and Ni0. Besides, the saturation magnetization (Ms) of FeNi@GR is 68.15 emu g−1, which has excellent magnetic response performance. This work not only provides a simple and efficient method to stabilize nZVI, but also reveals that using FeNi@GR is a promising approach for the remediation of water pollution.

Bimetallic FeNi nanoparticles immobilized by biomass-derived hierarchically porous carbon for efficient removal of Cr(VI) from aqueous solution

Nano zero-valent iron (nZVI) is an effective material for Cr(VI) treatment, however excessive agglomeration and surface oxidation limit its application. Herein, straw derived hierarchically porous carbon supported FeNi bimetallic nanoparticles (FeNi@HPC) was prepared for effective removal of Cr(VI) from water. FeNi nanoparticles were successfully loaded onto HPC with good dispersibility, and HPC caused an increase in specific surface area of FeNi nanoparticles. FeNi@HPC exhibited a significantly enhanced removal efficiency for Cr(VI) in comparison to Fe@HPC and FeNi NPs. The Ni doping content was further optimized, and the best Ni content in bimetallic NPs was estimated as 10 wt%. The conditions optimal for the activity of FeNi@HPC were assessed, and the highest removal efficiency equivalent to 30 mg L−1 of Cr(VI) was achieved at pH= 4.0 in 360 min with a dosage of 0.5 g L−1. Higher temperatures favored the removal of Cr(VI) and FeNi@HPC manifested the lowest activation energy as compared to Fe@HPC and FeNi NPs. The action mechanisms of FeNi@HPC presumably involved electron transfer from Fe0, Fe2+and atomic hydrogen. This work not only provide a cost-effective and available HPC material to stabilize nZVI but also revealed that using FeNi@HPC is a promising approach for the remediation of water pollution.

Carbothermal Synthesis of Ni/Fe Bimetallic Nanoparticles Embedded into Graphitized Carbon for Efficient Removal of Chlorophenol.

The reactivity of nanoscale zero-valent iron is limited by surface passivation and particle agglomeration. Here, Ni/Fe bimetallic nanoparticles embedded into graphitized carbon (NiFe@GC) were prepared from Ni/Fe bimetallic complex through a carbothermal reduction treatment. The Ni/Fe nanoparticles were uniformly distributed in the GC matrix with controllable particle sizes, and NiFe@GC exhibited a larger specific surface area than unsupported nanoscale zero-valent iron/nickel (FeNi NPs). The XRD results revealed that Ni/Fe bimetallic nanoparticles embedded into graphitized carbon were protected from oxidization. The NiFe@GC performed excellently in 2,4,6-trichlorophenol (TCP) removal from an aqueous solution. The removal efficiency of TCP for NiFe@GC-50 was more than twice that of FeNi nanoparticles, and the removal efficiency of TCP increased from 78.5% to 94.1% when the Ni/Fe molar ratio increased from 0 to 50%. The removal efficiency of TCP by NiFe@GC-50 can maintain 76.8% after 10 days of aging, much higher than that of FeNi NPs (29.6%). The higher performance of NiFe@GC should be ascribed to the significant synergistic effect of the combination of NiFe bimetallic nanoparticles and GC. In the presence of Ni, atomic H* generated by zero-valent iron corrosion can accelerate TCP removal. The GC coated on the surface of Ni/Fe bimetallic nanoparticles can protect them from oxidation and deactivation.

Ni-Fe bimetallic core-shell structured catalysts supported on biomass longan aril derived nitrogen doped carbon for efficient oxygen reduction and evolution performance

A simple two-step synthetic strategy for the preparation of Ni-Fe bimetallic nanoparticles with nitrogen doped carbon shell and support (FeNi@NC/NC) is successfully developed. Biomass longan aril serves not only as carbon source for catalyst supporting, but also a shell forming material and nitrogen doping receptor. When serving as electrocatalysts for oxygen electrode reaction, such bimetallic composite exhibits superior bi-functional electrocatalytic activities towards oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Benefiting from the high-conductive carbon shell and the coordination effect between NiFe alloy and nitrogen doped porous carbon support, the resultant FeNi@NC/NC achieved high durability over ORR and OER.

Nitrogen-doped graphene layer-encapsulated NiFe bimetallic nanoparticles synthesized by an arc discharge method for a highly efficient microwave absorber

NiFe@NC nanocomposites exhibit excellent microwave absorption benefiting from their core@shell structures and synergistic effects of dielectric/magnetic losses.

Removal of perchlorate from wastewater through adsorption and reductive degradation using Ni-Fe bimetallic nanoparticles supported on modified activated carbon: A simple strategy to degrade persistent pollutants

In the present study, nickel and iron (Ni/Fe) bimetallic nanoparticles (Ni-Fe NPs) were produced in the presence of activated carbon (AC) to prepare supported Ni/Fe bimetallic nanoparticles (Ni-Fe NPs/AC). The NPs were modified using cetylpyridinium chloride and used for the simultaneous adsorption and degradation of perchlorate. Synthesized Ni-Fe NPs/AC was characterized using FE-SEM, EDS, and XRD. The influential factors in the removal of perchlorate by Ni-Fe NPs/AC were optimized based on experimental design. According to the results, adsorption and degradation efficiencies were 96.98% and 78.81%, respectively, which could be achieved to the efficiency of nearly 100% by increasing the process time to 110 minutes. Reaction kinetics complied with the pseudo-first-order characteristics. Moreover, the rate constant of adsorption and degradation were estimated at 0.0848 and 0.0199 min-1 at 303 K, and the activation energy for adsorption and degradation was 42.39 and 12.47 kJ/mol, respectively. The proposed method could effectively remove perchlorate from well water and industrial wastewater. Therefore, Ni-Fe NPs/AC could be an effective nanomaterial for the complete degradation of perchlorate. This novel method could also remove persistent organic and inorganic pollutants and promote the industrial application of bimetallic NPs in environmental remediation.

Synergistic effect and degradation mechanism on Fe-Ni/CNTs for removal of 2,4-dichlorophenol in aqueous solution.

Fe-Ni bimetallic nanoparticles supported on CNTs (Fe-Ni/CNTs) were synthesized, characterized, and applied for removal of 2,4-dichlorophenol (2,4-DCP) in aqueous solution. The removal performance was enhanced drastically on Fe-Ni/CNTs with respect to monometallic Fe/CNTs. The synergistic effect between Fe-Ni nanoparticles and CNTs has been studied in detail. The research results indicated that the doping of Ni played an important role in promoting the catalytic degradation of 2,4-DCP. And the presence of CNTs not only could effectively reduce the aggregation of nanoparticles but also facilitate the mass transfer of 2,4-DCP and the formation of active atomic hydrogen during the catalytic process. In addition, the removal kinetics of 2,4-DCP by Fe-Ni/CNTs were in agreement with a pseudo-first-order model, and the rate constants were dependent on a number of factors including the initial concentration of 2,4-DCP, the dosage of Fe-Ni/CNTs, pH value of the solution, and doping amount of Ni. The degradation mechanism involved the adsorption by CNTs and catalytic reduction by Fe under the stimulating of Ni, and the preferred dechlorination followed the order of para-Cl > ortho-Cl. The study confirmed that Fe-Ni/CNTs had a potential to be a promising catalytic material for removal of chlorophenol and had a great prospect for practical application.

Comparative assessment of the decolorization of aqueous bromophenol blue using Fe nanoparticles and Fe-Ni bimetallic nanoparticles

Comparative assessment of the decolorization of aqueous bromophenol blue using Fe nanoparticles and Fe-Ni bimetallic nanoparticles

Synthesis of chitosan-stabilised bimetallic nanoparticles containing Fe and Ni and the reductive degradation of nimesulide

Chitosan (CHI)-stabilised Ni–Fe bimetallic nanoparticles (bNP/CHI) were synthesised varying the content of nickel and denoted as 2-bNP/CHI, 17-bNP/CHI, and 27-bNP/CHI. The nanoparticles were characterised using several techniques and used in the removal of nimesulide. XRD and Mössbauer analyses confirmed the formation of an amorphous structure containing Fe0 and Fe2O3 while the FT-IR analysis confirmed the presence of chitosan in the nanoparticles. A very high removal of nimesulide was obtained after only 15 min of treatment with the 17-bNP/CHI system. The by-product obtained after the reductive treatment was identified using the chromatography analysis coupled to the mass spectrometry technique.

Trichloroethene (TCE) hydrodechlorination by Ni[sbnd]Fe nanoparticles: Influence of aqueous anions on catalytic pathways

Amending bulk and nanoscale zero-valent iron (ZVI) with catalytic metals significantly accelerates hydrodechlorination of groundwater contaminants such as trichloroethene (TCE). The bimetallic design benefits from a strong synergy between Ni and Fe in facilitating the production of active hydrogen for TCE reduction, and it is of research and practical interest to understand the impacts of common groundwater solutes on catalyst and ZVI functionality. In this study, TCE hydrodechlorination reaction was conducted using fresh NiFe bimetallic nanoparticles (NiFe BNPs) and those aged in chloride, sulfate, phosphate, and humic acid solutions with concurrent analysis of carbon fractionation of TCE and its daughter products. The apparent kinetics suggest that the reactivity of NiFe BNPs is relatively stable in pure water and chloride or humic acid solutions, in contrast to significant deactivation observed of PdFe bimetallic particles in similar media. Exposure to phosphate at greater than 0.1 mM led to a severe decrease in TCE reaction rate. The change in kinetic regimes from first to zeroth order with increasing phosphate concentration is consistent with consumption of reactive sites by phosphate. Despite severe kinetic effect, there is no significant shift in TCE 13C bulk enrichment factor between the fresh and the phosphate-aged particles. Instead, pronounced retardation of TCE reaction by NiFe BNPs in deuterated water (D2O) points to the importance of hydrogen spillover in controlling TCE reduction rate by NiFe BNPs, and such process can be strongly affected by groundwater chemistry.

La0.6Ca0.4Fe0.8Ni0.2O3−δ – Sm0.2Ce0.8O1.9 composites as symmetrical bi-electrodes for solid oxide fuel cells through infiltration and in-situ exsolution

Symmetrical solid oxide fuel cells (SOFCs) have more attractive benefits such as a simplified fabrication procedure and enhanced stability and reliability compared to conventional SOFC. In this study, we fabricated a La0.6Ca0.4Fe0.8Ni0.2O3−δ (LCFN) – Sm0.2Ce0.8O1.9 (SDC) composite via infiltration and simple mixing methods and evaluated it as both anode and cathode for symmetrical SOFCs (S-SOFC). X-ray diffraction (XRD) and scanning electron microscope (SEM) results demonstrated that Fe-Ni bimetallic nanoparticles were exsolved in-situ from LCFN perovskite and distributed on the surface of LCFN backbone after H2 reduction at high temperature. The electro-activity towards oxygen reduction reaction (ORR) at the cathode side could be further improved by infiltration of SDC nanoparticles. A combined effect of in-situ ex-solution of Fe-Ni as well as infiltration of SDC nanoparticles synergistically promoted the hydrogen oxidation reaction at the anode and ORR activity at the cathode. Furthermore, the S-SOFC showed good stability in H2 at 800 °C for 140 h and reliable redox stability undergoing a repeated H2-air cycles. These recent results indicate that the LCFN-SDC composite electrodes were promising bi-electrode materials for high performance and cost-effective S-SOFCs.

Examining selenium reduction mechanisms on Ni-Fe bimetallic nanoparticles using non-stationary kinetic modeling

Bimetallic nanoparticles (BNPs) are being increasingly used for the remediation of organic and inorganic contaminants. Most heterogeneous reactions on BNPs occur primarily due to: (1) adsorption of contaminant species on the active surface sites; (2) chemical reduction on the catalyst surface; and (3) sorption of the products from the catalyst surface. In this work, we identify the rate determining step for selenium, particularly Se (VI) reduction on Ni-Fe BNPs using kinetic data modeling. A non-stationary kinetic model, without any preliminary assumptions of a rate limiting step was developed. The kinetic data on Se (VI) reduction was fitted to the non-stationary to determine the rate constants. The non-stationary model suggested adsorption limiting step for Se (VI) reduction on Ni-Fe BNPs. With increase in BNP loading (i.e., increase in number of active surface sites), reaction rates also increased linearly. Deviation from linearity was observed due to the deactivation of the BNPs. The loss in catalytic activity can be attributed to the formation of metal oxide on the catalyst particle, resulting in loss of active sites. Even though selenium reduction may no longer occur on the newly formed metal oxides, selenium removal via adsorption can occur. Prediction of the occupied site concentration on the Ni-Fe BNPs suggested possible in-situ regeneration of the active site due to galvanic coupling of the bimetals.

Degradation of doxorubicin to non-toxic metabolites using Fe-Ni bimetallic nanoparticles

Contamination of water and soil with Pharmaceutical and Personal Care Products (PPCP); although present at very lower concentrations, has raised alarming issues regarding their toxicity to ecosystem. Their mitigation through biological and chemical treatments have been a area of great interest in recent past. One such attempt is made wherein degradation of doxorubicin (DOX); a well known anticancer agent, is explored with Fe-Ni bimetallic nanoparticles (Fe-Ni NP’s). These nanoparticles degrade DOX through chemisorptive exothermic pseudo-multilayer film-diffusion mineralisation process as evident from adsorption and intra-particle mechanisms. The degradation mechanism is established from metabolites formed during its degradation by LC–MS analysis. It is observed that chemical degradation route closely resembles with that of metabolic pathway mediated by aldo-keto reductase (AKR); a family of oxido-reductase enzyme involving ROS and iron-sulphur clusters. The toxicity of degraded DOX solution evaluated against two breast cancer cell lines viz. MCF-7 and MDA-MB-231 and a normal cell line HEK-293 revealed that the metabolites are non-toxic in nature. These findings are further corroborated with chemo-informatics studies using Molinspiration Properties Calculator. Formation of oxide layer on the nanoparticle surface evident from XPS analysis that decreases their recycling capacity. Thus, Fe-Ni NP’s are exhibiting properties like a functional mimic of AKR that degrade DOX in an eco-friendly manner.

A versatile sensor for determination of seven species based on NiFe nanoparticles

A facile one-pot route was developed to synthesis NiFe bimetallic nanoparticles via a controlled co-reduction of Ni(II) acetylacetonate and Fe(II) acetylacetonate in oleylamine (OAm). Due to its unique properties originating from the synergistic effects of transition metals, NiFe exhibited excellent electrochemical catalytic activities. The electrochemical sensor based on carbon supported NiFe nanoparticles (NiFe/C) was constructed to determine various small biomolecules, and intensively showed high selectivity towards the oxidation of ascorbic acid (AA), dopamine (DA), uric acid (UA) and four DNA bases (guanine (G), adenine (A), thymine (T) and cytosine (C)), with large peak separations of 179mV (AA-DA), 123mV (DA-UA), 128mV (G-A), 274mV (A-T), 112mV (T-C) and little mutual interference. The detection limits were AA (1.0μM), DA (0.1μM), UA (0.1μM), G (0.25μM), A (0.25μM), T (10μM) and C (10μM) at S/N=3, respectively. The feasibility of the proposed sensor for real sample analysis was also investigated. These results demonstrate that NiFe bimetallic catalyst is a promising candidate of electrode material for determination of various analytes, which make it a fascinating sensor with versatile application.

Effective and stable FeNi@ N-doped graphene counter electrode for enhanced performance dye sensitized solar cells

N-doped FeNi@graphene is introduced as effective and stable non-precious counter electrode for the dye sensitized solar cells. After preparation of graphene oxide using the chemical route, the obtained product has been refluxed in presence of nickel acetate, ferrous acetate and urea at 150°C for 12h. Then, the solid product was mixed with melamine and sintered under nitrogen atmosphere at 850°C. The invoked characterization techniques affirmed formation of N-doped graphene decorated by FeNi bimetallic nanoparticles. In dye sensitized solar cell, the prepared material revealed good performance as counter electrode as the estimated efficiency was 4.12% with a photocurrent and an open circuit voltage of 8.96mA/cm2 and 0.73V, respectively, Moreover, the cyclic voltammetry measurements indicated very good catalytic activity and distinct stability.