Fe Bimetallic Catalysts Research Articles

Secondary Alcohol-Driven α-Olefination and α-Alkylation of Nitriles: Introducing a Heterogeneous Ru–Fe Bimetallic Catalyst

Secondary Alcohol-Driven α-Olefination and α-Alkylation of Nitriles: Introducing a Heterogeneous Ru–Fe Bimetallic Catalyst

Strengthening Hydrogen Spillover in Ceria-Supported Co–Fe Bimetallic Catalysts for Boosting Ammonia Synthesis

Strengthening Hydrogen Spillover in Ceria-Supported Co–Fe Bimetallic Catalysts for Boosting Ammonia Synthesis

Selective hydrogenolysis of furfural to 1,2-pentanediol over a Pt–Fe/MT catalyst under mild conditions

A Pt–Fe bimetallic catalyst is developed to produce 1,2-pentanediol from furfural under mild conditions of 140 °C and 0.1 MPa H2, affording by far the highest production rate.

Preparation of aromatic hydrocarbons from pinecone pyrolysis synergistically catalyzed by Ca–Fe and HZSM-5

In this study, a combination of Ca–Fe and HZSM-5 catalysts for enhancing the aromatic hydrocarbons yields from pinecone pyrolysis was proposed. The catalysts performance and the enhanced mechanism of aromatic hydrocarbons generation were investigated by pyrolysis–gas chromatography–mass spectrometry (Py-GC/MS) and a bench-scaled fixed bed reactor. The catalysts crystallization and pore structure characteristics were characterized by X-ray diffraction (XRD) and N2 adsorption/desorption. The results showed that the combination of Ca–Fe and HZSM-5 catalysts produced the largest peak area and the highest relative content of aromatic hydrocarbons relative to HZSM-5, CaO/HZSM-5 and Fe/HZSM-5 catalysts. Relative to single HZSM-5 catalytic pyrolysis, the introduction of Ca–Fe components increased the yield of aromatics, especially increased the yield of benzene, toluene, ethylbenzene and xylene (BTEX) to 17.21 mg/g, with an increase of 61.60 %. The heterotopic arrangement of pinecone, Ca–Fe catalyst and HZSM-5 catalyst facilitated the production of high-quality aromatic hydrocarbons relative to the in situ catalytic pyrolysis technique. The Ca–Fe bimetallic catalyst decomposed the primary volatiles from pinecone pyrolysis into oxygenated compounds with smaller molecular weights, thereby increasing the proportions of pyrolysis volatiles entering the HZSM-5 channels, and subsequently enhancing the yield of aromatic hydrocarbons. This study implies that the combination of Ca–Fe and HZSM-5 catalyst is a promising approach for converting biomass materials into aromatic hydrocarbons.

Preparation of graphene supported Ni–Fe bimetallic nanocatalyst and its catalytic upgrading and viscosity reduction performance for heavy oil

Graphene supported single metal catalyst can improve the dispersion of active components and enhance the viscosity reduction effect of heavy oil. However, there is little research on graphene-supported bimetallic catalysts in the field of heavy oil upgrading and viscosity reduction. In this paper, super heavy oil of Liaohe Oilfield was taken as the research object. Graphene was selected as the carrier material, and nickel and iron chlorides were used as precursors. Graphene-supported nickel-iron bimetallic nanocatalysts were prepared by solvothermal method, and their synthesis feasibility was proved by microscopic characterization. Then the prepared catalyst was used in the evaluation experiment of catalytic upgrading and viscosity reduction performance of Liaohe heavy oil. By analyzing the parameters of oil samples before and after catalytic upgrading and viscosity reduction, the catalytic upgrading and viscosity reduction effect was evaluated and the viscosity reduction mechanism was revealed. The results showed that the viscosity reduction rate of heavy oil with graphene supported Ni–Fe bimetallic catalyst was 42.38%. With the aid of decalin, the viscosity reduction rate of heavy oil could reach 71.43%. At this time, the content of heavy components, the average molecular weight of heavy components and the aromaticity fA of oil samples decreased after catalytic upgrading and viscosity reduction, while the aromatic condensation degree HAU/CA and the branched chain index BI increased, and the modification effect was significant. Among them, the average molecular weight of asphaltene decreased from 2266 to 1444, with the most obvious decrease. The decrease of heteroatom content in asphaltene led to a significant decrease in intermolecular force and hydrogen bonding, which was the main reason for the catalytic upgrading and viscosity reduction of heavy oil by graphene supported Ni–Fe bimetallic catalyst.

Alkaline ethanol oxidation on porous Fe/Pd–Fe nanostructured bimetallic electrodes

In this work, to prepare nanostructured and porous Fe/Pd–Fe bimetallic catalysts, the iron coating is applied firstly onto the copper substrate by the electrochemical deposition method. Subsequently, iron-zinc alloy coating is deposited on the underlayer iron. Eventually, by immersing this alloy coating in an alkaline solution containing palladium ions, the palladium will replace the zinc, resulting in porous Fe/Pd–Fe catalysts. The X-ray diffraction (XRD) technique was used for the characterization of the physical properties of the as-prepared electrocatalysts. Their electrocatalytic activity was studied by electrochemical methods such as cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). The XRD results showed that the zinc element was the main component of the Fe/Zn-Fe alloy and was replaced by palladium as a result of leaching-galvanic replacement. The electrochemical investigations showed that a new porous Fe/Pd-Fe bimetallic catalyst had higher electro-catalytic activity and stability than pure Pd and Fe electrodes for ethanol electro-oxidation in alkaline media. The superiority of the Fe/Pd–Fe catalyst is related to the high surface area and a synergistic effect between Fe and Pd in Fe/Pd–Fe catalysts. Therefore, the nanostructured Fe/Pd–Fe catalysts can be proposed as potential anode materials for alkaline ethanol fuel cells. A new porous Fe/Pd–Fe bimetallic catalyst shows higher electro-catalytic activity and stability than pure Pd and Fe electrodes for ethanol electro-oxidation in alkaline media. The superiority of the Fe/Pd–Fe catalyst is related to the high electrochemical surface area and a synergistic effect between Fe and Pd in Fe/Pd–Fe catalysts

Elucidating the structural evolution of highly efficient Co–Fe bimetallic catalysts for the hydrogenation of CO2 into olefins

Constructing Co-Fe bimetallic catalyst is of high research value for CO2 conversion based on its outstanding traits, however, its activity-structure relationship is still confusing. Herein, a series of Na-promoted Co-Fe bimetallic catalysts differing in composition or proximity were prepared and their structural evolution during reduction and reaction was elucidated. It was found that the Co1Fe2 catalyst with Co/Fe molar ratio of 1/2 and close proximity was conducive to rapid reduction of CoFe2O4 to CoxFey alloy, and further carbonization to stable χ-(CoxFe1−x)5C2 alloy carbide as the active phase for olefin formation, thus exhibiting superior performance without evident deactivation for over 500 h on-stream. Especially at high space velocity, it achieved an unprecedented olefin space-time yield up to 1810.8 mg·gcat−1·h−1, showing a potential application in micro-channel reactor. Moreover, the alloy carbide plays a unique role in facilitating CO2 adsorption, and inhibiting the hydrogenation of surface intermediates as well as suppressing carbon deposition.

Ce–Fe bimetallic oxide catalysts for CO catalytic oxidation at a high concentration of SO2

The doping of Fe into the CeO2 lattice played a positive role in enhancing the CO oxidation activity and SO2-poisoning resistance of Ce0.7Fe0.3.

Carbon Nanotube prepared by catalytic pyrolysis as the electrode for supercapacitors from polypropylene wasted face masks.

The massive global consumption and discarded face masks drove by the ongoing spread of COVID-19. Meantime, incineration and landfill discarded face masks would result in severe environmental pollution and infectious hazards. Herein a suggestion to recycle polypropylene waste masks into CNTs by an environmentally friendly and high-added value disposal process was proposed, and which was prepared as supercapacitor electrode materials for energy storage attempting. The CNTs were prepared from waste masks by catalysis pyrolysis with Ni–Fe bimetallic catalysts. Especially, the bamboo-like structure CNT was obtained with Ni/Fe molar ratio is 3. This structure owned a high specific capacitance compared to other standard CNTs. Its specific capacitance could reach 56.04 F/g (1 A/g) and has excellent cycling stability with a capacitance retention rate of the material is 85.41% after 10,000 cycles. Besides, the assembled capacitor possesses a good energy density of 4.78 Wh/kg at a power density of 900 W/kg. Thus, this work provides a sustainable and cost-effective strategy for disposing waste masks into high-valuable CNT, and their potential application for supercapacitors was also studied and exploited. It would provide a new idea for recycling and utilizing other polypropylene wastes such as medical devices.Graphical abstract

Synthesis, Characterization, and Photocatalytic, Bactericidal, and Molecular Docking Analysis of Cu-Fe/TiO2 Photocatalysts: Influence of Metallic Impurities and Calcination Temperature on Charge Recombination.

This research evaluated the potential photocatalytic efficiency of synthesized Cu–Fe/TiO2 photocatalysts against organic contaminants and biocontaminants through various synthesis methods (Cu-to-Fe ratio, metal loading, and calcination temperature) and reaction parameters (photocatalyst dose, irradiation time, and different initial methyl orange (MO) concentrations). In addition, the best photocatalysts were characterized through Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), differential reflectance spectroscopy (DRS), and X-ray photoelectron spectroscopy (XPS) analysis techniques. The best metal loading was 1 wt % with 5:5 Cu/Fe ratio and 300 °C calcination temperature (5Cu–5Fe/TiO2-300) having 97% MO decolorization. Further analysis indicates that the metal presence does not generate new channels for de-excitation but clearly affects the intensity and decreases charge recombination. The behavior of the photoluminescence intensity is (inversely) proportional to the activity behavior through the series, indicating that the main catalytic effect of Fe and Cu relates to charge recombination and that the Cu–Fe bimetallic catalyst optimizes such function. Moreover, the best-engineered photocatalysts asserted impactful bacteriostatic efficacy toward the tested Escherichia coli strain (in 30 min), and therefore, molecular docking studies were used to predict the inhibition pathway against E. coli β-lactamase enzyme. The photocatalyst had a high negative docking score (−5.9 kcal mol–1) due to intense interactions within the active site of the enzyme. The molecular docking study revealed that the ligand could inhibit β-lactamase from producing its bactericidal activity.

Exploring the mechanism of ZrO2 structure features on H2O2 activation in Zr–Fe bimetallic catalyst

Bimetallic Fenton catalyst has attracted widespread attention in refractory organics removal. Herein, we firstly investigated the influence of ZrO2 structure features on H2O2 activation in Zr-Fe bimetallic catalyst. The results show that the heterojunction structure will be formed after high temperature calcination, which makes the ability of Zr-Fe bimetallic catalyst to activate H2O2 for bisphenol A degradation is 3.1 times higher than that of α-Fe2O3 without Zr doping. Through characterization and density functional theory, it was identified that compared to (1 1 0) interface, the adsorption energy of H2O2 on iron sites at (1 1 0)-(1 0 0) interface reduced by 1.27 kJ mol−1, while the Fe–O bond length in the stable configuration of Fe-OOH increased by 0.16 Å, which was beneficial to the association and dissociation of H2O2 on iron sites. Besides, the surface -OH of amorphous ZrO2 in Zr-Fe bimetallic catalyst synthesized under low temperature conditions could promote HO2•/O2•- formation through the surface electron transfer, accelerating the Fe(III) reduction. In conclusion, this study reveals the influence of environment-friendly ZrO2 structure features on H2O2 activation, proposes a new insight into strengthening the synergistic effect between bimetals, and provides a reference for the structural optimization of bimetallic catalysts.

Enhancement of anodic oxidation of formic acid on Pd–Fe bimetallic nanoparticles by thermal treatment

The surface composition and catalytic properties of Pd–Fe bimetallic catalysts with identical bulk composition can be continuously tuned by treatment at different temperatures. The activity of these catalysts in formic acid oxidation was related to the treatment temperature. The thermal treatment temperatures ranged from 400 to 600 °C. The Pd–Fe nanoparticles are characterized by an array of analytical techniques including TEM (transmission electron microscopy), XRD (X-ray diffraction), ICP (inductively coupled plasma) and HS-LEIS (low energy ion scattering spectroscopy). The electrocatalytic activity is examined using cyclic voltammetric and chronoamperometric measurements. The Pd–Fe/C catalyst with 500 °C shows the highest electrocatalytic activity for formic acid oxidation, with a current activity 3 times higher than that of before treated Pd–Fe/C catalyst, 5.6 times higher than that of commercial Pt/C catalyst. The migration of Pd to the surface on the nanoparticle catalysts as well as the electrochemical active surface area of the PdFe–H catalysts was shown to play a major role in enhancing the electrocatalytic activity for catalyst. These findings provided important insights into the correlation between the electrocatalytic activity and the treatment temperature of the nanoengineered bimetallic catalysts.

A highly dispersed Co–Fe bimetallic catalyst to activate peroxymonosulfate for VOC degradation in a wet scrubber

This work synthesized a highly dispersed Co–Fe bimetallic catalyst with uncalcined SBA-15 as the support, which was very efficient for PMS activation and gaseous toluene degradation in the wet scrubbing waste gas treatment system.

Correlating C═C, C═O, and C═N Hydrogenation Activity with Hydrogen Binding Energies on Ni–Fe Bimetallic Catalysts

Ni-Fe bimetallic catalysts have been found active in various hydrogenation reactions. Previous reports have hypothesized many explanations to demonstrate the promotion effect of Fe. However, these ...

One-step synthesis of biochar-supported potassium-iron catalyst for catalytic cracking of biomass pyrolysis tar

In this work, K–Fe bimetallic catalyst supported on porous biomass char was synthesized via a one-step synthesis method by pyrolysis of biomass (peanut shells) after impregnation of a small amount of potassium ferrate (PSC–K2FeO4), and was evaluated for the cracking of biomass pyrolysis tar. Control experiments using the pure char (PSC) and char-supported catalysts after impregnation of KOH (PSC–KOH) and FeCl3 (PSC–FeCl3) were also performed for comparison. The as-prepared PSC-K2FeO4 possessed a porous structure with the dispersion of particles/clusters of Fe metal, K2CO3 and KFeO2 on the char support. Tar cracking experiments showed that the PSC-K2FeO4 exhibited excellent catalytic activity on the cracking of biomass pyrolysis tar in the temperature range of 600–800 °C, and the obtained tar conversion efficiencies were obviously higher than that in the control experiments, particularly at relatively lower temperatures (600 and 700 °C). The yields of combustible gas compounds including CO, H2 and CH4 increased significantly using PSC-K2FeO4 as the catalyst due to the enhanced tar cracking and reforming reactions. The porous structure and the active crystal structures of the spent catalyst were well retained, indicating the potential for efficient and long-term utilization of the catalyst in tar cracking. PSC-K2FeO4 exhibited excellent reusability during the five times reuse under the same conditions without regeneration, which showed almost no obvious decrease in the tar conversion efficiency and gas yields.

Coal fly ash‐derived mesoporous SBA‐15 as support material for production of liquid hydrocarbon through Fischer–Tropsch route

AbstractThe supernatant solution of silicate species extracted from coal fly ash (CFA) by NaOH fusion is used under acidic conditions with surfactant pluronic P‐123 to prepare the mesoporous silica (SBA‐15). Structural properties of prepared SBA‐15 are found close to those prepared by pure chemicals. Furthermore, the synthesized mesoporous silica (SBA‐15) from CFA is used as support in Fischer–Tropsch synthesis (FTS). The obtained mesoporous material has a surface area of 643 m2/g and a pore size of 8.24 nm. Co–Fe bimetallic catalyst containing 15 wt% of cobalt and 5 wt% of iron is prepared by incipient wetness impregnation of cobalt nitrate and iron nitrate salts over CFA‐derived SBA‐15. These mesoporous support and catalyst are characterized by X‐ray diffraction (XRD), N2 adsorption–desorption, H2‐temperature‐programmed reduction (TPR), NH3‐temperature‐programmed desorption (TPD), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). FTS experiment is showing 65.53% of C5+ selectivity. The results indicate that the nanosubstrate material derived from CFA may be used as support for FTS activity with further improvements.

Aqueous phase semihydrogenation of alkynes over Ni–Fe bimetallic catalysts

Bimetallic Ni–Fe catalysts (Ni/Fe, 1 : 1, 1 : 3, and 3 : 1) are synthesized and explored for their catalytic activity in semihydrogenation of internal alkynes using H2 gas in water–ethanol solution.

Co-, Cu- and Fe-Doped Ni/Al2O3 Catalysts for the Catalytic Decomposition of Methane into Hydrogen and Carbon Nanofibers

The catalytic decomposition of methane (CDM) process produces hydrogen in a single stage and avoids CO2 emission thanks to the formation of high added value carbon nanofilaments as a by-product. In this work, Ni monometallic and Ni–Co, Ni–Cu, and Ni–Fe bimetallic catalysts are tested in the CDM reaction for the obtention of fishbone carbon nanofibers (CNF). Catalysts, in which Al2O3 is used as textural promoter in their formulation, are based on Ni as main active phase for the carbon formation and on Co, Cu, or Fe as dopants in order to obtain alloys with improved catalytic behaviour. Characterization of bimetallic catalysts showed the formation of particles of Ni alloys with a bimodal size distribution. For the doping content studied (5 mol. %), only Cu formed an alloy with a lattice constant high enough to be able to favor the carbon diffusion through the catalytic particle against surface diffusion, resulting in higher carbon formations, longer activity times, and activity at 750 °C; whereas Ni, Ni–Co, and Ni–Fe catalysts were inactive. On the other hand, Fe also improved the undoped catalyst performance presenting a higher carbon formation at 700 °C and the obtention of narrow carbon nanofilaments from active Ni3Fe crystallites.

Mechanistic Insight into C–C Coupling over Fe–Cu Bimetallic Catalysts in CO2 Hydrogenation

Density functional theory (DFT) calculations were carried out to investigate the mechanism of CO2 hydrogenation in production of C1 and C2 hydrocarbons over Cu–Fe bimetallic catalyst. CH* is found to be the most favorable monomeric species for production of CH4 and C2H4 via C–C coupling of two CH* species and subsequent hydrogenation. On the bimetallic Cu–Fe(100) surface at 4/9 ML Cu coverage, the energetically preferred path for CH* formation goes through CO2* → HCOO* → HCOOH* → HCO* → HCOH* → CH*, in which both the HCOO* → HCOOH* and HCO* → HCOH* steps have substantial barriers. The bimetallic surface suppresses CH4 formation and is more selective to C2H4 due to the higher hydrogenation barrier of CH2* species relative to those for C–C coupling and CH–CH* conversion to C2H4. On monometallic Fe(100) surface, CH* formation goes through a path of CO2* → CO* → HCO* → HCOH* → CH*, different from that identified on Cu–Fe(100). The hydrogenation of HCO* to HCOH* is the rate-limiting step that controls CO2 conv...

Low-temperature grafting of carbon nanotubes on carbon fibers using a bimetallic floating catalyst

The degradation mechanism of CFs experiencing the catalytic growth of CNTs on their surface through high-temperature CVD was revealed using microstructural analysis. Catalysts nanoparticles, if their energy was high enough to diffuse into CFs, generated micro-voids in CFs and reduced their tensile strength. Herein, we report a new low-temperature processing route to grow CNTs on CF surfaces without mechanically degrading the CFs. The use of a Ni–Fe bimetallic catalyst was key to achieving the growth of CNTs at low temperature, e.g., 500°C. Catalyst diffusion into the CFs during CVD was inhibited at this temperature, which facilitated uniform growth of CNTs on only the CF surfaces and minimized internal structural changes of the CFs.